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nexflash technologies, inc. 1 preliminary nxsf016f-1201 12/12/01 ? this document contains preliminary information. nexflash reserves the right to make changes to its product at any time without notice in order to improve design and supply the best possible product. we assume no responsibility for any errors which may appear in this publication. ? copyright 2001, nexflash technologies, inc. preliminary december 2001 nx25f011b, NX25F021B, nx25f041b 1m-bit, 2m-bit, and 4m-bit serial flash memories with 4-pin spi interface
2 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b table of contents 1m-bit, 2m-bit, and 4m-bit ............................................................................................................................... .......... 1 serial flash memories with 4-pin spi interface ................................................................................. ......... 1 features ............................................................................................................................... ...................................... 4 description ............................................................................................................................... ................................ 4 functional overview ............................................................................................................................... .............. 5 pin descriptions ............................................................................................................... ........................................ 5 package ............................................................................................................................... ................................ 5 serial data input (si) ......................................................................................................... ................................... 6 serial data output (so) ........................................................................................................ ............................... 6 serial clock (sck) ............................................................................................................. .................................. 6 chip select (cs) ............................................................................................................... ................................... 6 write protect (wp) ............................................................................................................. .................................. 6 hold or ready/busy (hold or r/b) ............................................................................................... ....................... 6 power supply pins (vcc and gnd) ................................................................................................ ........................ 6 serial flash memory array ...................................................................................................... ................................. 7 serial sram .................................................................................................................... ......................................... 8 using the sram independent of flash memory ..................................................................................... .............. 9 write protection ............................................................................................................... ......................................... 9 configuration register ............................................................................................................................... ............... 9 write protect range and direction, wr[3:0], wd ................................................................................. ............... 10 read clock edge, rce ........................................................................................................... ........................... 10 table 2a. write protect range sector selection (hex) ........................................................................... ............. 11 table 2b. write protect range sector selection (hex) ........................................................................... ............. 11 table 2c. write protect range sector selection (hex) ........................................................................... ............. 11 hold-r/b, hr[1:0] ............................................................................................................................... ............. 11 status register bit descriptions ............................................................................................... .............................. 12 compare not equal, cne ......................................................................................................... .......................... 12 power detect, pd ............................................................................................................... ................................ 12 write enable/disable, we....................................................................................................... ............................ 12 command set ............................................................................................................................... ......................... 13 command set for the nx25f011b, NX25F021B and nx25f041b serial flash memory ..................................... 15 serial flash sector commands ....................................................................................................................... 16 read from sector (52h) ............................................................................................................................... .......... 16 read from sector with auto increment (50h) ..................................................................................... .................... 16 read from sector low frequency (51h) and .......................................................................................................... 16 read from sector low frequency with auto increment (5bh) ....................................................................... ......... 16 write enable (06h) ............................................................................................................................... ................... 16 write disable (04h) ............................................................................................................................... .................. 16 write to sector through sram (f3h) ............................................................................................. ........................ 18 serial sram commands ............................................................................................................................... ........ 19 write to sram command (72h) .................................................................................................... ......................... 19 read from sram (71h) ........................................................................................................... ............................... 19 transfer all of sram to sector (f3h) ........................................................................................... .......................... 20 transfer all of sector to sram (53h) ........................................................................................... .......................... 20 compare sector to sram (8dh) ................................................................................................... ......................... 21 configuration and status commands ............................................................................................................ 21 read configuration register (8ch) ......................................................................................................................... 21 write non-volatile configuration register (8ah) ............................................................................................................................... ......................... 22
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 3 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 table of contents (cont?d) read status register (84h) ..................................................................................................... ............................... 22 clear compare status (89h) ............................................................................................................................... .... 23 set power detection bit (03h) .................................................................................................. .............................. 23 reset power detection bit (09h) ................................................................................................ ............................. 23 read device information sector (15h) ........................................................................................... ......................... 24 special sector commands ............................................................................................................................... .. 24 erase sector (f1h) ............................................................................................................. .................................... 24 erase block (f4h) .............................................................................................................. .................................... 25 write-only to sector (f2h) ..................................................................................................... ................................. 25 compatibility commands for 25xxxa series devices ............................................................................... .. 26 read from sram (81h) ........................................................................................................... ............................... 26 read configuration register (8bh) ......................................................................................................................... 27 read status register (83h) ..................................................................................................... ............................... 27 transfer sector to sram clocked (54h) .......................................................................................... ....................... 28 compare sector to sram clocked (86h) ........................................................................................... .................... 28 sector format .................................................................................................................. ...................................... 29 high data integrity applications ............................................................................................... ............................... 29 write/verify flow .............................................................................................................. ...................................... 29 grouping static and frequently updated data ............................................................................................................................... ........................... 29 abosolute minimum ratings .............................................................................................................................. 3 0 operating ranges ............................................................................................................................... .................. 30 dc electrical characteristics (preliminary) ................................................................................................. 30 ac electrical characteristics (preliminary) ................................................................................................. 31 serial output timing ........................................................................................................... ................................. 32 serial input timing ............................................................................................................ .................................... 32 hold timing .................................................................................................................... .......................................... 32 packaging information ............................................................................................................................... ......... 33 200-mil plastic soic package code: (s) ......................................................................................... ................... 33 packaging information ............................................................................................................................... ......... 34 330 mil plastic soic package code: (j) ......................................................................................... ................... 34 packaging information ............................................................................................................................... ......... 35 plastic tsop - 28-pins package code: type i (v) ................................................................................ ............... 35 preliminary designation ............................................................................................................................... ..... 36 important notice ............................................................................................................................... .................... 36 ordering information ............................................................................................................................... .......... 36 life support policy ............................................................................................................ ................................. 36 trademarks: ............................................................................................................................... .................................. 36
4 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b features flash storage for resource-limited systems ? ideal for portable/mobile and microcontroller-based applications that store voice, text, and data 0.35 nexflash memory technology ? 1m/2m/4m-bit with 512/1024/2048 sectors ? small 264-byte sectors ? erase/write time of 7.5 ms/sector (typical) ? optional 8kb (32 sector) block erase for faster programming ultra-low power for battery-operation ? single 5v or 3v supply for read and erase/write ? 1 ma standby current, 2.5 ma active @ 3v (typical) ? low frequency read command for lower power 4-pin spi serial interface ? easily interfaces to popular microcontrollers ? clock operation as fast as 20 mhz on-chip serial sram ? single 264-byte read/write sram buffer ? use in conjunction with or independent of flash ? off-loads ram-limited microcontrollers special features for media-storage applications ? byte-level addressing for reads and sram writes ? transfer or compare sector to sram ? versatile hardware and software write-protection ? in-system electronic part number option ? removable serial flash module package option ? serial flash development kit description the nx25f011b, NX25F021B, and nx25f041b serial flash memories provide a storage solution for systems limited in power, pins, space, hardware, and firmware resources. they are ideal for applications that store voice, text, and data in a portable or mobile environment. using nexflash's patented single transistor eeprom cell, the devices offer a high-density, low-voltage, low-power, and cost-effective non-volatile memory solution. the devices operate on a single 5v or 3v (2.7v-3.6v) supply for read and erase/write with typical current consumption as low as 2.5 ma active and less than 1 a standby. sector erase/write speeds as fast as 7.5 ms increase system performance, minimize power-on time, and maximize battery life. the nx25f011b, NX25F021B, and nx25f041b provide 1m-bit, 2m-bit, and 4m-bit of flash memory organized as 512, 1024, or 2048 sectors of 264 bytes each. each sector is individually addressable through basic serial-clocked com- mands. the 4-pin spi serial interface works directly with popular microcontrollers. special features include: on-chip serial sram, byte-level addressing, double-buffered sector writes, transfer/compare sector to sram, hardware and software write protection, alternate oscillator frequency, elec- tronic part number, and removable serial flash module package option. development is supported with the pc-based sfk-spi serial flash development kit.
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 5 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 functional overview an architectural block diagram of the nx25f011b, NX25F021B, and nx25f041b is shown in figure 2. key elements of the architecture include: spi interface and command set logic serial flash memory array serial sram and program buffer write protection logic configuration and status registers device information sector device information sector (dis) (read only) write protect logic nexflash 1, 2 and 4 m-bit serial flash memory array 512, 1024 and 2048 byte-addressable sectors of 264 bytes each organized in 16, 32, and 64 blocks of 32 sectors per block row decode ( 512, 1024 and 2048 sectors) 2112 8 8 8 sram (264 bytes) column decode, sense amp latch and data compare logic high-voltage generators sector-address latch data 9/10/11 write control logic wp hold or read/busy logic configuration register status register spi command and control logic byte-address latch/counter 9 16 hold or r/ b sck cs si so figure 2. nx25f011b, NX25F021B, and nx25f041b architectural block diagram pin descriptions package the nx25f011b, NX25F021B, and nx25f041b are available in a 28-pin tsop (type i) surface mount package. the nx25f011b and NX25F021B are available in either an 8-pin soic and a 14-pin tsop package (contact nexflash for information on the 14-pin tsop package). the nx25f041b is also available in a 28-pin soic package. see figure 3a, 3b and table 1 for pin assignments. all interface and supply pins are on one side of the tsop package. the ? no connect ? (nc) pins are not connected to the device, allowing the pads and the area around them to be used for routing pcb system traces. the devices are also available in a cost-effective and space-efficient removable serial flash module package.
6 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b table 1. pin descriptions si serial data input so serial data output sck serial clock input cs chip select input wp write protect input hold , r/ b hold input or read busy output vcc power supply the so pin will enter a high-impedance state and power consumption will decrease to standby levels unless pro- gramming is in process, in which case standby will resume when programming is complete. write protect ( wp wp wp wp wp ) the write protect input ( wp ) works in conjunction with the write protect range set in the configuration register bits. when wp is asserted (active low) the entire flash memory array is write protected. when high, any flash memory sector can be written to unless its address is within the write protect range that is set in the configuration register. hold or ready/busy ( hold hold hold hold hold or r/ b b b b b ) this multifunction pin can serve either as a hold input ( hold ) or as a ready-busy output (r/ b ). the pin function is user-programmable through the non-volatile configuration register. factory-programmed as a no-connect, the pin can be reconfigured as a ready-busy output or as a hold input by setting the configuration register. see the configuration register section of this data sheet for further details. power supply pins (vcc and gnd) the nx25f011b, NX25F021B, and nx25f041b support single power supply read and erase/write operations in 5v and 3v versions. typical active power is as low as 2.5 ma for the 3v version with standby current less than 1 a. serial data input (si) the spi bus serial data input (si) provides a means for data to be written to (shifted into) the device. serial data output (so) the spi bus serial data output (so) provides a means for data to be read from (shifted out of) the device during a read operation. when the device is deselected ( cs =1 or hold =0) the so pin is in a high-impedance state. serial clock (sck) all commands and data written to the serial input (si) are clocked relative to the rising edge of the serial clock (sck). all data read from the serial data output (so) is clocked relative to the falling or rising edge of sck as specified in the non-volatile configuration register. the data output clock edge is factory-programmed to the default condition of the falling edge, allowing compatibility with standard spi systems. clock rates of up to 20 mhz are supported. chip select ( cs cs cs cs cs ) the nx25f011b, NX25F021B, and nx25f041b are selected for operation when the chip select input ( cs ) is asserted low. sck must be low when ( cs ) is asserted to a low state. upon power-up, an initial low-to-high transition of cs is required before any command sequence will be acknowledged. the device can be deselected to a non-active state when cs is brought high. once deselected, figure 3b. nx25f011b, NX25F021B, and nx25f041b pin assignments, 28-pin tsop (type i) hold-r/b nc wp nc nc vcc gnd nc nc nc cs sck si so nc nc nc nc nc nc nc nc nc nc nc nc nc nc 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 si sck hold r/ b cs 1 2 3 4 8 7 6 5 so gnd vcc wp figure 3a. nx25f011b and NX25F021B pin assignments, 8-pin soic figure 3c. nx25f041b pin assignments, 28-pin soic gnd nc nc cs sck si so nc nc nc nc nc nc nc vcc nc nc wp nc hold -r/ b nc nc nc nc nc nc nc nc 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 7 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 serial flash memory array the nx25f011b, NX25F021B, and nx25f041b serial flash memory arrays are organized as 512, 1024, and 2048 sectors of 264-bytes (2,112 bits) each, as shown in figure 4. the block size of the device is 32 sectors, yielding 16, 32 and 64 blocks for the nx25f011b, NX25F021B, and nx25f041b. the serial flash memory of the nx25f011b, NX25F021B, and nx25f041b is byte-addressable for read operations. this allows a single byte, or specified sequence of bytes, to be read without having to clock an entire 264-byte sector out of the device. data can be read directly from a sector in the flash memory array by using a read from sector command. data can be written to the flash memory array one sector (264-bytes) at a time through the serial sram using a write to sector command or a transfer sram to sector com- mand. no pre-erase is needed. in stead, the device incorporates an auto-erase-before-write feature that automatically erases the addressed sector at the beginning of the write operation. after a sector has been written, the memory array will become busy while it is programming the specified non-volatile memory cells of that sector. this busy time will not exceed t wp during which time the flash array is unavailable for read or write access. the device can be tested to determine the array ? s availability using the ready/busy status that is available during most read commands, through the status register, or on the ready/ busy pin. after sector programming is complete and the device is ready, it is recommended to verify the data in the sector with the data in the sram using the compare command, (see write/ verify flow towards the end of this data sheet). byte 0 000h sector 0 000h 25f011 s[8:0] 25f041 s[10:0] sector address: byte address: b[8:0] block 0 sector 31 1fh block 64 sector 2047 7ffh block 16 sector 511 1ffh sector 2016 7e0h sector 480 1e0h byte1 001h byte 2-261 002h-105h 1m-bit, 2m-bit, or 4m-bit serial flash memory array 512, 1024, and 2048 byte-addressable sectors of 264-bytes each. organized in 16, 32 and 64 blocks of 32 sectors per block. byte 262 106h byte 263 107h byte1 001h byte 2-261 002h-105h byte 262 106h byte 0 000h byte 263 107h byte 0 000h byte 1 001h byte 2-261 002h-105h byte 262 106h byte 0 000h byte 1 001h byte 2-261 002h-105h byte 262 106h byte 263 107h byte 263 107h block 0 sector 31 1fh sector 0 000h sector 0 000h 25f021 s[9:0] block 0 sector 31 1fh block 32 sector 1023 3ffh sector 992 3e0h figure 4. nx25f011b, NX25F021B, and nx25f041b serial flash memory array
8 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b serial sram one of the most powerful features of the nx25f011b, NX25F021B, and nx25f041b is the integrated serial sram. the main purpose of the serial sram is to serve as the primary buffer for sector data to be written into the serial flash memory array. using the write to sector command, data is first shifted into the sram from the spi bus. when the command sequence has been completed, the entire 264-bytes is written to the selected sector. see erase/write cycle timing (t wp ). the sram is fully byte-addressable. thus, the entire 264-bytes, a single byte, or a sequence of bytes can be read from, or written to the sram. this allows the sram to be used as a temporary work area for read-modify-write operations prior to a sector write. the transfer sector to sram command allows the con- tents of a specified sector of flash memory to be moved to the sram. this can be useful when only a portion of a sector needs to be altered. in this case the sector is first transferred to the sram, where modifications are made using the write to sram command. once complete, a transfer sram to sector command is used to update the sector. the compare sector command allows the contents of the sram to be compared with the specified sector in memory. the result of the compare is set in the status register. this command is useful for performing a fast verify of the last sector write operation (see write/ verify flow towards the end of this data sheet). this command can be useful when re-writing multi-sector files that have only minor changes from the previous write. if the new data in the sram is the same as the previously written data, the sector write can be skipped. used in this way, the command saves time that would have been used for re-programming. it also extends the endurance of the flash memory cells. spi command and control logic sck cs si so status register configuration register compare sector to sram read from device information sector note: 1. a single byte, several bytes, or all bytes of a flash sector, the sram, or program buffer may be addressed. 2. all double lines represent implied connections or actions. serial flash memory array 512, 1024 and 2048 byte-addressable sectors of 264-bytes each device information sector write to sector (via sram) serial sram read from or write to sram transfer sector to sram read from sector figure 5. command relationships of the spi interface, serial flash memory array and sram
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 9 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 using the sram independent of flash memory the sram can be used independently of flash memory operations for lookup tables, variable storage, or scratch pad purposes. if the flash memory needs to be written to while sram is being used for a different purpose, the contents can be temporarily stored to a sector and then transferred back again when needed. the sram can be especially useful for ram-limited microcontroller-based systems, eliminating the need for external sram and freeing pins for other purposes. it can also make it possible to use small pin-count microcontrollers, since only a few pins are needed for the interface instead of the 20-40 pins required for parallel bus-oriented flash devices. write protection the nx25f011b, NX25F021B, and nx25f041b provide ad- vanced software and hardware write protection features. software-controlled write protection of the entire array is handled using the write enable and write disable commands. hardware write protection is possible using the write protect pin ( wp ). write-protecting a portion of flash memory is accommodated by programming a write protect range in the configuration register. for applications needing a portion of the memory to be permanently write-protected or a fixed configuration register value, a onetime programmable write protection feature is supported. contact nexflash for further information. configuration register the configuration register stores the current configuration of the hold -r/ b pin, read clock edge and write protect range (figure 7). the configuration register is accessed using the write and read configuration register commands. the non-volatile configuration register will maintain its setting even when power is removed. to avoid unnecessary programming of the configuration register, and to save time during power-up, the configuration register should be read upon power-up and compared to the intended setting before sending a write configuration register command (figure 6). figure 6. flow chart for checking the configuration register upon power-up system power-up read device information sector, verify device density and type read configuration register verify bits are set as needed configuration setting is correct? yes write configuration register to correct setting application routines no
10 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b the factory default setting for the configuration register is cf8-cf0 is: 0 0000 1001 b (w rite protect range = none, read uses falling edge of the clock, and pin 1 = no connect). bits cf15-cf9 are reserved. when writing to the configuration register cf15-cf9 should be 0. when reading, the settings of cf15-cf9 should be ignored. write protect range and direction, wr[3:0], wd the write protect range and direction bits wr[3:0] and wd are located at configuration bits cf[7:4] and cf[3] respec- tively. the write protect range and direction bits select how the array is protected. they work in conjunction with the wp input pin, valid only if wp is inactive (high). wr[3:0] can select write protection of all sectors, none of the sectors, or specific sectors grouped in blocks of 32 (~8 kb). the wd bit specifies whether the protected block range starts from the first sector, address 0 (000h), or from the last sector (1ffh for the nx25f011b, 3ffh for the NX25F021B, and 7ff for the nx25f041b). table 2a, 2b and 2c lists the write protect sector range for the devices. once protected, all further writes to sectors within the range will be ignored. the factory default setting is with no write protected sectors, wr=[0,0,0,0] and wd=1. read clock edge, rce the read clock edge bit (rce) is located at configuration bit location cf[2]. it selects which edge of the clock (sck) is used while reading data out of the device. although the spi protocol specifies that data is written during the rising edge and read on the falling edge of the clock, if required, the output can be driven on the rising edge of the clock by setting the configuration registers rce bit to a 1. using the rising edge of clock for data reads may be beneficial to the timing of some high-speed systems. the factory default setting is the falling edge of sck for standard spi. rce=0 read data is output on the falling edge of sck (standard spi). rce=1 read data is output on the rising edge of sck (fast spi). cf15:8 (reserved) cf7 cf6 cf5 cf4 cf3 cf2 cf1 cf0 wr3 wr2 wr1 wr0 wd rce hr1 hr0 write protect range write protect direction read data clock edge hold-ready/busy pin function figure 7. configuration register bit locations
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 11 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 hold hold hold hold hold -r/ b b b b b , hr[1:0] the hold-ready/busy ( hold -r/ b ) bits hr1 and hr0 are located at bits cf[1:0] of the configuration register. these two bits select one of four possible functions: no connect, hold input, r/ b output, or r/ b output with open drain. the factory setting for the pin is ? no connect ? . hr1 hr0 pin configuration 00 hold input 0 1 no connect 10r/ b output (open drain) 11r/ b output configured as a r/ b output, the pin can serve as a system interrupt. when r/ b is high, the array is ready to be programmed. when r/ b is low, it is busy programming. if configured with an open-drain, an external pull-up resistor should be used. as a hold input, the pin can be used in conjunction with the cs and sck pin to suspend a serial command sequence without resetting the command. this can be useful if a command is in process and a higher priority task on the same spi bus needs to be attended to. to table 2c. write protect range sector selection (hex) write protect (nx25f041b) range config. bits write protected sectors wr3 wr2 wr1 wr0 wd=0 wd=1 00 00 none none 0 0 0 1 000 - 01fh 7 e0 - 7ffh 0 0 1 0 000 - 03fh 7 c0 - 7ffh 0 0 1 1 000 - 05fh 7 a0 - 7ffh 0 1 0 0 000 - 07fh 7 80 - 7ffh 0 1 0 1 000 - 09fh 7 60 - 7ffh 0 1 1 0 000 - 0bfh 7 40 - 7ffh 0 1 1 1 000 - 0dfh 7 20 - 7ffh 1 0 0 0 000 - 0ffh 7 00 - 7ffh 1 0 0 1 000 - 11fh 6 e0 - 7ffh 1 0 1 0 000 - 13fh 6 c0 - 7ffh 1 0 1 1 000 - 15fh 6 a0 - 7ffh 1 1 0 0 000 - 17fh 6 80 - 7ffh 1 1 0 1 000 - 19fh 6 60 - 7ffh 1 1 1 0 000 - 1bfh 6 40 - 7ffh 11 11 all all table 2a. write protect range sector selection (hex) write protect (nx25f011b) range config. bits write protected sectors wr3 wr2 wr1 wr0 wd=0 wd=1 00 00 none none 0 0 0 1 000 - 01fh 1 e0 - 1ff 0 0 1 0 000 - 03fh 1 c0 - 1ff 0 0 1 1 000 - 05fh 1 a0 - 1ff 0 1 0 0 000 - 07fh 1 80 - 1ff 0 1 0 1 000 - 09fh 1 60 - 1ff 0 1 1 0 000 - 0bfh 1 40 - 1ff 0 1 1 1 000 - 0dfh 1 20 - 1ff 1 0 0 0 000 - 0ffh 1 00 - 1ff 1 0 0 1 000 - 11fh 0 e0 - 1ff 1 0 1 0 000 - 13fh 0 c0 - 1ff 1 0 1 1 000 - 15fh 0 a0 - 1ff 1 1 0 0 000 - 17fh 0 80 - 1ff 1 1 0 1 000 - 19fh 0 60 - 1ff 1 1 1 0 000 - 1bfh 0 40 - 1ff 11 11 all all table 2b. write protect range sector selection (hex) write protect (NX25F021B) range config. bits write protected sectors wr3 wr2 wr1 wr0 wd=0 wd=1 00 00 none none 0 0 0 1 000 - 01fh 3 e0 - 3ff 0 0 1 0 000 - 03fh 3 c0 - 3ff 0 0 1 1 000 - 05fh 3 a0 - 3ff 0 1 0 0 000 - 07fh 3 80 - 3ff 0 1 0 1 000 - 09fh 3 60 - 3ff 0 1 1 0 000 - 0bfh 3 40 - 3ff 0 1 1 1 000 - 0dfh 3 20 - 3ff 1 0 0 0 000 - 0ffh 3 00 - 3ff 1 0 0 1 000 - 11fh 2 e0 - 3ff 1 0 1 0 000 - 13fh 2 c0 - 3ff 1 0 1 1 000 - 15fh 2 a0 - 3ff 1 1 0 0 000 - 17fh 2 80 - 3ff 1 1 0 1 000 - 19fh 2 60 - 3ff 1 1 1 0 000 - 1bfh 2 40 - 3ff 11 11 all all
12 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b suspend a command, hold must be brought low while cs and sck are low. with hold low, further data on the si pin is ignored (even while sck is clocked) and the so pin goes to a high-impedance state. to resume the command sequence, hold must be brought high when cs and sck are low. see timing diagrams. status register bit descriptions the status register provides status of the flash array ? s ready/busy condition (r/ b ), transfers between the sram and program buffer (tx), write-enable/disable (we), and compare not equal (cne). the register can be read using the read status register command (figure 8). ready/busy status, busy the busy status bit is located at bit st[7] of the status register. testing the busy bit is one of several ways to check ready/busy status of the array. at power-up the busy bit is reset to 0. busy=1 the device is busy programming. busy=0 the deivce is ready for further use. sram transfer all or compare all, tr the tr status bit is located at bit st[6] of the status register. the bit provides status primarily for use during the transfer all sector to sram command and compare all sector to sram command. an active state 1 indi- cates a transfer is in process and the sram a rray is not available for use. the device will indicate a busy state while the tr bit is active. upon power up the tr bit resets to 0. tr=1 transfer or compare all in process. tr=0 transfer or compare all not in process. write enable/disable, we the we status bit is located at bit st[4] of the status register. the bit provides write protect status of global write enable and write disable commands. upon power- up the we bit resets to 0. we=1 write enabled, array can be written to. we=0 write disabled, array can not be written to. busy tr st7 x st6 we st5 x st4 cne st3 x st2 pd st1 st0 x = reserved read/busy sram transfer or compare power detect flash array write enable/disable sector-sram compare not equal figure 8. status register bit locations compare not equal, cne the cne status bit is located at bit st[3] of the status register. the bit provides a cumulative comparison result during a compare sector with sram command. the cne bit is reset to a 0 upon power-up or after a clear compare bit command is executed. cne=1 sector and sram contents are not equal. cne=0 sector and sram are equal or cne bit reset. power detect, pd the power detect bit works in conjunction with the set power detection and reset power detection commands and is primarily used for removable media applications. the set power detect command must be issued before the pd bit can be used for power detection. pd=0 power has been removed pd=1 power has not been removed
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 13 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 command set the nx25f011b, NX25F021B, and nx25f041b have a powerful command set that is fully controlled through the spi bus. command relations are shown in figure 5 and a list of commands and their associated address, status, clock, and data bytes are shown in table 3. detailed clock timing of the read sector and write sector command sequences are shown in figures 9 and 10. after power up, a device enters an idle state that will maintain until cs pin is asserted low. all commands are entered from the spi serial data input (si) pin on the rising edge of sck while cs is asserted low. all command, address, and configuration bits are shifted into the device with most-significant-bit-first. data bits read from the device are shifted out with least significant byte first (i.e., byte-00h, byte-01h,...). the bit order within each byte is most-significant-bit first (i.e.,d7,...d0). all com- mands are completed by asserting the cs pin high. note that the entire 264-byte contents of a flash sector or the sram does not have to be accessed all at once. read, write, transfer clocked, and compare clocked com- mands allow for byte addressing. thus a single byte, or clocked sequence of bytes, can be accessed at any starting location within the 264-byte boundary as specified by the byte-address field.
14 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b 00000000 c[7:0] command s[15:0] sector address b[15:0] byte address rb[15:0] ready/busy status (9999h=ready) high-z so output is driven 1 st byte of data 2nd byte of data 16 clocks high-z last byte of data n-bytes of data idle cs sck si sck si so sck so cs sck so c7 c6 c5 c4 c3 c2 c1 c0 0 0 0 0 0 s10 s9 s8 s7 s6 s5 s4 s3 s2 s1 s0 0 0 0 0 0 0 0 b8 b7 b6 b5 b4 b3 b2 b1 b0 0 0 0 0 0 0 0 0 1 00110 011 0011 0 0 1 d7 d6 d5 d4 d3 d2 d1 d0 d7 d6 d4 d5 d3 d2 d1 d0 d7 d6 d5 d4 d3 d2 d1 d0 idle figure 9. read from sector command sequence d7 d6 d5 d4 d3 d2 d1 d0 c[7:0] command s[15:0] sector address b[15:0] byte address last byte of data n-bytes of data t wp program time cs sck si sck si cs sck si c7 c6 c5 c4 c3 c2 c1 c0 0 0 0 0 0 s10 s9 s8 s7 s6 s5 s4 s3 s2 s1 s0 0 0 0 0 0 0 0 b8 b7 b6 b5 b4 b3 b2 b1 b0 d7 d6 d5 d4 d3 d2 d1 d0 idle 1 st byte of data 2nd byte of data d7 d6 d5 d4 d3 d2 d1 d0 0 0 0 0 0 0 0 0 8 clocks figure 10. write to sector command sequence
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 15 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 command set for the nx25f011b, NX25F021B and nx25f041b serial flash memory n- bytes command name byte 0 byte 1-2 byte 3-4 (italics indicate device output) sector commands read from sector 52h sector address byte address 0000h ready/busy read data read from sector w/autoinc (3) 50h sector address 0000h 0000h ready/busy read data read from sector low freq. 51h sector address byte address 0000h ready/busy read data read from sector 5bh sector address 0000h 0000h ready/busy read data w/autoinc low freq (3) write enable (1) 06h 00h write disable (1) 04h 00h write to sector (through sram) (2) f3h sector address byte address write data 00h serial sram commands write to sram (2), (3) 72h byte address write data 00h read from sram (1),(3) 71h byte address 00h read data transfer all of sram to sector f3h sector address 0000h transfer all of sector to sram (3) 53h sector address 0000h 0000h compare sector to sram (3) 8dh sector address byte address 0000h configuration and status commands read configuration (1), (3) 8ch configuration write non-volatile 8ah configuration 0000h configuration register (1) read status register (1), (3) 84h status (8 bits) clear compare status (1) 89h set power detection bit (1), (3) 03h reset power detection bit (1), (3) 09h read device information sector 15h 0000h byte address 0000h ready/busy dis data special sector commands (3),(4) erase sector f1h sector address 0000h erase block f4h block address 0000h write-only to sector through sram f2h sector address byte address write data 00h compatibility commands for 25xxxa series devices read from sram 81h 0000h byte address 0000h read/busy read data write to sram 82h 0000h byte address write data 00h read configuration register 8bh 0000h 0000h 0000h ready/busy configuration read status register 83h 0000h 0000h 0000h ready/busy status transfer sector to sram clocked 54h sector address byte address n*00h 00h compare sector to sram clocked 86h sector address byte address 0000h ready/busy bit compare of data notes: 1. command may be used when device is busy 2. command may not be used when device is busy and tr bit=0 3. new ? b ? series command 4. warning: read description of these commands before using to ensure reliable operation.
16 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b read from sector command sector address* byte address** 16 clocks si so 52h, 50h, 51h, 53h s[15:0] b[15:0] 0000h rb[15:0] first byte - last byte read/busy status read sector data *the sector address only uses bits [8:0], [9:0] or [10:0] depending on the density **the byte address only uses bits [8:0]. byte address must be 0000h for auto increment commands serial flash sector commands read from sector (52h) reading from a sector is accomplished by first bringing cs low then shifting in the read from sector command (52h) followed by its 16-bit ? sector-address ? field. although the sector-address field is 16-bits, only bits s[8:0] for the nx25f011b (0-1ffh), s[9:0] for the NX25F021B (0-3ffh), s[10:0] for the nx25f041b (0-7ffh) are used. the uppermost sector address bits are not used but must be clocked using 0 for data. next a 16-bit ? byte-address ? field is clocked into the device to designate the starting location within the 264-byte sector. only b[8:0] of the byte-address field are used; the uppermost bits are not used but must be clocked in (use 0 for data). only byte-addresses of 0 to 107h (264 bytes) are valid. following the byte-address field, 16 control clocks are required with data=0. the serial data output (so) will change from a high-impedance state and begin to drive the output with ready/busy status rb[15:0]. if so uses the rising edge of clock (configuration register rce=1), the output will be driven after the last control clock. if so uses the falling edge of clock (rce=0), the output will be driven on the next falling edge of clock. if the array is not busy, the output status will be 9999h, followed by the sector data on the so pin. if the array is busy, the status will be 6666h, and the command should be terminated and restarted after a ready state occurs. the data field is shifted out with the least significant byte first (i.e., byte-00h, byte-01h, ...). the bit order within each byte is the most significant bit first (i.e.,d7,...d0). the byte-address is internally incremented to the next higher byte address as the clock continues. when the highest byte-address (107h) is reached, the address counter rolls over to byte-0h and continues to increment. assert- ing the cs pin high completes (or terminates) the command. detailed timing for the read from sector command is shown in figure 10. read from sector with auto increment (50h) the read from sector with auto increment command operates similar to the standard read from sector com- mand except that after the last bit of the current sector is clocked the next sequentially addressed sector will be automatically selected for reading without requiring the nine byte command sequence to be issued. this allows the entire device or a large number of sectors to be read out with a single command. read from sector low frequency (51h) and read from sector low frequency with auto increment (5bh) the read from sector at low frequency command (51h) and read from sector low frequency with auto increment command (5bh) can reduce power consumption during read operations by 25%-40% when the system clock frequency is 1 mhz or lower. the command sequences are identical to the standard commands.
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 17 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 write disable command 8 clocks si 04h 00h so write disable (04h) the write disable command (04h) protects the flash memory array from being programmed. once issued, fur- ther write to sector or transfer sram to sector commands will be ignored. the status of the write protect state can be read in the status register. the write disable command sequence is completed by asserting cs high after eight additional clocks. write enable command 8 clocks si 06h 00h so write enable (06h) upon power-up, the flash memory array is write- protected until the write enable command (06h) has been issued. the wp pin must be inactive while writing the command for the write enable to be accepted. the status of the device ? s write protect state can be read in the status register. the write enable command sequence is completed by asserting cs high after eight additional clocks.
18 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b after the byte-address has been loaded, data is shifted into the 264-byte sram, which serves as a temporary storage buffer. existing data in the sram will be written over. the byte order of the data shifted into the sram is least significant byte first (i.e., byte-00h, byte-01h,...). the bit order within each byte is most significant bit first (i.e., d7,...d0). the byte-address is automatically incre- mented to the next higher byte address as the clock continues. when the last byte address to be written is reached, the command can be completed with an additional eight control clocks (with data=0) followed by asserting cs high. if the clock continues to increment past the highest byte-address (107h), the address counter will roll over to byte 0h. after the cs pin is brought high, the data in the sram is transferred to the specified sector in memory array. see t wp timing specifications. during this time the array and sram w ill be ? busy ? and will ignore further array-related commands until complete. all ready/busy status indi- cators will indicate a busy status. detailed clock timing for the write to sector command is shown in figure 11. write to sector through sram (f3h) before writing to a sector in the flash memory array, all hardware and software write protection must be in an enabled state. this means that the wp pin must be in a high state, a write enable command must have previ- ously been issued, and the sector location that is to be written to must be outside the write protect range set in the configuration register. additionally, the ready/busy status should be checked to confirm that the memory array is available to be written to. writing to a sector is accomplished by first bringing cs low and shifting in the write to sector command (f3h) followed by a 16-bit ? sector-address ? field. although the sector-address field is 16-bits, only bits s[8:0] for the nx25f011b (0-1ffh), s[9:0] for the NX25F021B (0-3ffh), or s[10:0] for the nx25f041b (0-7ffh) are used. the uppermost sector address bits are not used but must be clocked in (use 0 data). following the sector address, a 16-bit ? byte-address ? field is clocked into the device to designate the starting location within the 264- byte sector. only bits b[8:0] of the byte-address field are used and only values of 0-107h (264 bytes) are valid. write to sector command 8 clocks si f3h s[15:0] b[15:0] first byte - last byte 00h so sector address* byte address** write sector data *the sector address only uses bits [8:0], [9:0] or [10:0] **the byte address only uses bits [8:0] program time ( t wp )
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 19 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 serial sram commands write to sram command (72h) the write to sram command (72h) provides access to the 264-byte sram independently of any flash memory array operation. when cs is asserted high to complete the command, the contents of the sram will be main- tained until overwritten through another command or the power is removed. using the write to sram command, data can be loaded in preparation of writing to a sector in memory and then transferred to a selected sector using the transfer sram to sector command. the tr bit in the status register should be checked first if transfer sector to sram or compare sector to sram commands are used. write to sram command 8 clocks si 72h b[15:0] first byte - last byte 00h so byte address* write sector data *the byte address only uses bits [8:0] read from sram command byte address* 8 clocks si so 71h b[15:0] 00h read sram data *the byte address only uses bits [8:0] first byte-last byte read from sram (71h) the read from sram command (71h) provides access to the 264-byte sram independent of any flash memory array operations. the tr bit in the status register should be checked first if transfer sector to sram or compare sector to sram commands are used.
20 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b transfer all of sram to sector (f3h) the transfer sram to sector command (f3h) will write the existing contents of the sram to the speci- fied sector in memory. the command sequence is identical to that of the write to sector command except that immediately after the sector address field s[15:0] and 16 control clocks, the cs pin is asserted high. this automatically transfers the 264-bytes of sram data to the specified sector in the memory array. during this time, the array will be busy. since the entire 264-bytes are transferred, the byte-address field b[15:0] is not used. transfer sram to sector command sector address* 16 clocks si so f3h s[15:0] 0000h *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density program time ( t wp ) *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density transfer sector to sram command sector address* 32 clocks si so 53h s[15:0] 0000 0000h transfer time ( t xs ) transfer all of sector to sram (53h) the transfer sector to sram command (53h) allows the contents of a sector to be transferred directly to the sram without having to clock or read the sector out of the device and rewrite it into the sram. during the transfer, the so output is in a high-impedance state and the tr bit in the status register will be set to a "1" state. when the last byte address is transferred the tr bit in the status register will be cleared. note that the transfer sector to sram clocked command (54h) can also be used if partial transfers are required.
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 21 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 compare sector with sram command sector address* sector address* 16 clocks si so 8dh s[15:0] b[15:0] 0000h *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density compare time ( t xs ) compare sector to sram (8dh) the compare sector to sram command (8dh) does a bit-by-bit comparison of the data stored in the addressed sector against data in the sram. the tr bit will be 1 during the transfer compare operation. if any of the compared bits are not equal, then the compare not equal (cne) bit in the status register is set to a 1. this bit will stay set until a clear compare status command has been issued. note that the compare sector to sram clocked command can be used if partial compares are required. this command is very useful for performing a fast verify of the last sector write operation. this verify provides for the highest data integrity. read configuration register command si so 8ch cf{15:0}* read configuration bits *the cf register only uses bits [7:0] configuration and status commands read configuration register (8ch) the read configuration register command provides access to the configuration register, which stores the current configuration of the hold -r/ b pin, read clock edge, write protect range, and alternate oscillator frequency (figure 7). a 16-bit configuration data field cf[15:0] provides the contents of the configuration register. although the field is 16-bits long, only bits cf[7:0] are used. all other upper bits are reserved for future features.
22 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b read status register (84h) the read status register command provides access to the status register and its status flags for ready/busy (r/ b ), sram and program buffer transfer operations (tx), write enable/disable ( we ), and compare not equal (cne) (figure 8). an 8-bit status field st[7:0] provides the contents of the status register. read status register command si so 84h st[7:0] read status register bits write non-volatile configuration register (8ah) the write configuration register command provides ac- cess to the configuration register which stores the current configuration of the hold -r/ b pin, read-data clock edge, write protect range, and alternate oscillator frequency. the configuration register is non-volatile. once set using the write configuration register command, the contents will maintain even when power is removed. because the register ? s state is stored in non-volatile memory, there is a finite endurance limit to the number of times it can be written to. to limit the number of writes, it is recommended that before writing to the configuration register it should first be read from using the read configuration register command. if no change is required, the write configuration register command can be skipped. this process will help *the cf register only uses bits [7:0] configuration bits* write configuration register command 16 clocks si 8ah cf[15:0] 0000h so program time ( t wp ) extend the endurance of the configuration register bits and eliminate additional programming ? busy ? time. the write configuration register command sequence starts with the command byte (8ah) followed by a 16-bit field that specifies configuration register bit settings. although the field is 16-bits long, only bits cf[7:0] are used. all other upper bits are reserved and must be clocked using 0 for data. after an additional 16 control clocks using 0 for data, the command can be completed by asserting cs high. the device will become busy for a short time ( t wp ) while the non-volatile memory cells of the configuration register are programmed.
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 23 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 clear compare status command 8 clocks si 89h 00h so clear compare status (89h) the clear compare status command (89h) works in con- junction with the compare sector to sram command and the status register. if any of the compared bits are not equal, then the compare not equal (cne) bit in the status register is set to a 1. the clear compare status command must be executed to reset the cne bit to a 0. set power detection bit (03h) the set power detection bit command (03h) can be used to detect if power has been removed from the device. the command works in conjunction with the power detect (pd) status bit. upon power up the pd bit is cleared to 0. the pd bit can be set to a 1 using the set power detection bit command. once set, if a power down condition occurs (vcc voltage < 2v) the pd bit will reset to 0. this function is especially useful for applications using nexflash serial flash modules or other removable media. set power detection bit 8 clocks si 03h 00h so reset power detection bit (09h) the reset power detection bit command (09h) can be used to force the power detect status bit in the status register to a 0 state. (see set power detection bit command (03h). reset power detection bit 8 clocks si 09h 00h so
24 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b read device info. sector command 16 clocks byte address* 16 clocks si so 15h 0000h b[15:0] 0000h rb[15:0] first byte - last byte read/busy status read sector data *the byte address only uses bits [8:0] read device information sector (15h) the read device information command provides access to a read-only sector that can be used to electronically identify the nexflash serial flash device being inter- faced to. information available includes: part number, density, voltage, temperature range, package type, and any special options. this can be extremely useful for systems that need to accommodate optional densities (e.g., both 1m-bit or 2m-bit). in this case the firmware can interrogate the device information sector and determine the density. the device information sector also includes a list of any restricted sectors that might exist in the device. contact nexflash for more detailed information on the device information sector format. special sector commands erase sector (f1h) the erase sector command (f1h) will erase a sector to an ? all 1s ? state, during this time the array will be "busy." this command can be used in conjunction with the write only to sector through sram command (f2h) to achieve faster program performance in applications that can accommo- date pre-erase. (see t eo in ac characteristics for erase timing). *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density erase sector command sector address* 16 clocks si so f1h s[15:0] 0000h transfer time ( t eo )
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 25 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 erase block (f4h) the erase block command (f4h) will erase a block of 32 sectors to an ? all 1s ? state, during this time the array will be "busy." this command can be used in conjunction with the write only to sector through sram command (f2h) to achieve faster program performance in applications that can accommodate pre-erase. (see t eo in ac characteris- tics for erase and write timing). *the block address only uses bits [8:5], [9:5] or [10:5] depending on device density. lowest four bit [4:0] must be 0h erase block block address* 16 clocks si so f4h blk[15:0] 0000h transfer time ( t eo ) write only to sector command 8 clocks si f2h s[15:0] b[15:0] first byte - last byte 00h so sector address* byte address** write sector data *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density **the byte address only uses bits [8:0] program time ( t wp ) write-only to sector (f2h) the write-only to sector through sram command (f2h) will write a pre-erased sector in about half the time of the standard write to sector through sram command (f3h), during this time the array will be "busy." this command can be used in conjunction with the erase sector com- mand (f1h) or erase block command (f4h) to achieve faster program performance in applications that can accommodate pre-erase. (see t wo inac characteristics for erase and write timing). warning: to ensure data integ- rity this command should only be issued after an erase command.
26 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b write to sram (82h) the write to sram command (82h) provides access to the 264-byte sram independently of any flash memory array operation. the command is similar to the write to sector command sequence except that the sector address field s[15:0] is replaced by all 0 bits. when cs is asserted high to complete the command, the contents of the sram will be maintained until overwritten through another command or the power is removed. using the write to sram command, data can be loaded in prepara- tion of writing to a sector in memory and then transferred to a selected sector using the transfer sram to sector command. write to sram command 8 clocks si 82h 0000h b[15:0] first byte - last byte 00h so 16 clocks byte address* write sector data *the byte address only uses bits [8:0] read from sram command 16 clocks byte address* 16 clocks si so 81h 0000h b[15:0] 0000h rb[15:0] first byte - last byte read/busy status read sram data *the byte address only uses bits [8:0] compatibility commands for 25xxxa series devices read from sram (81h) the read from sram command (81h) provides access to the 264-byte sram independent of any flash memory array operations. the command is similar to the read from sector command except for the sector address field s[15:0] which is replaced with all 0 bits.
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 27 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 read configuration register command 16 clocks 16 clocks 16 clocks si so 8bh 0000h 0000h 0000h rb[15:0] cf{15:0}* read/busy status read configuration bits *the cf register only uses bits [7:0] read configuration register (8bh) the read configuration register command provides access to the configuration register, which stores the current configuration of the hold -r/ b pin, read clock edge, write protect range, and alternate oscillator frequency (figure 7). the command sequence is similar to the read from sector command except that the sector address field s[15:0] and the byte-address field b[15:0] are replaced with all 0 bits. after 16 control clocks and after the ready/busy status field has been clocked through, a 16-bit configuration data field cf[15:0] provides the contents of the configuration register. although the field is 16-bits long, only bits cf[7:0] are used. all other upper bits are reserved for future features. read status register (83h) the read status register command provides access to the status register and its status flags for ready/busy (r/ b ), sram and program buffer transfer operations (tx), write enable/disable ( we ), and compare not equal (cne) (figure 8). the command sequence is similar to the read from sector command except that the sector address field s[15:0] and the byte-address field b[15:0] are replaced by all 0 bits. after 16 clocks and the ready/busy status field rb[15:0] has been read, an 8-bit status field st[7:0] provides the contents of the status register. read status register command 16 clocks 16 clocks 16 clocks si so 83h 0000h 0000h 0000h rb[15:0] st[7:0] read/busy status read status register bits
28 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b transfer sector to sram command 8 clocks si 54h s[15:0] b[15:0] si=00h during byte ttansfers 00h so sector address* byte address** 8 clocks per byte trasnfered from first byte to last byte *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density **the byte address only uses bits [8:0] transfer sector to sram clocked (54h) the transfer sector to sram clocked command (54h) allows the contents of a sector to be transferred directly to the sram without having to read the sector out of the device and rewrite it into the sram. the command is similar to the write to sector command except that instead of inputting data from the si pin, the data is taken from the specified sector and is transferred to the sram. every eight clocks on sck, a byte from the specified sector to the sram will be transferred. although data on si is ignored, it is recom- mended to write data bytes of 00h in order to support the clocking requirements. during the transfer, the so output is in a high-impedance state. when the last byte address is transferred, the command can be completed by issuing eight more control clocks and asserting cs high. if the clock continues to increment past the highest byte-address (107h), the address counter will roll over to byte-0h. this command can also be used to load partial sectors into sram compare sector with sram command sector address* byte address** 16 clocks si so 86h s[15:0] b[15:0] 0000h rb[15:0] first byte - last byte read/busy status bit compare of sector and sram *the sector address only uses bits [8:0], [9:0] or [10:0] depending on device density **the byte address only uses bits [8:0] compare sector to sram clocked (86h) the compare sector to sram command does a bit-by-bit comparison of the data stored in the addressed sector against data in the sram. the command is similar to the read from sector command except that data is not read out of the serial output pin (so). instead, the so pin provides a bit-by-bit compare of each sector and sram bit. a high (1) per bit will be output if the bit compare is equal. a low (0) per bit will be output if the bit compare is not equal. the compare can start from any location in the 264-byte range as specified by the byte-address field b[15:0]. the byte-address counter is automatically incremented and will wrap around to the first address (0h) if it passes the last address (107h). if any of the compared bits are not equal, then the compare not equal (cne) bit in the status register is set to a 1. this bit will stay set until a clear compare status command has been issued. this command can also be used to load partial sectors into sram
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 29 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 sector format the memory array of standard serial flash devices are factory programmed to a full erase state with all bits set to ? 1 ? (ffh). nexflash also offers restricted sector devices (with ? -r ? suffix) which may provide a more cost effective alternative to standard devices that have 100% valid sectors. restricted sector devices have a limited number of sectors that do not meet manufacturing programming criteria over the specified operating range. the first bye of each good sector in a ? -r ? device is pre-programmed during manufacturing with a tag/sync value of c9h. although this byte location of the sector can be changed, it is recom- mended that it be maintained and incorporated into the application ? s sector formatting. the tag/sync values serve two purposes. first, they provide a sync-detect that can help verify if the command sequence was clocked into the device properly. secondly, they serve as a tag to identify a fully functional (valid) sector. for defective sectors, the first byte is tagged with a pattern other than c9h. in addition to individual sector tagging, all restricted sectors for a given device are listed in the device information sector. for more information see the latest version of device information sector application note sfan-02. high data integrity applications data storage applications that use flash memory or other non-volatile media must take into consideration the possi- bility of noise or other adverse system conditions that may affect data integrity. for those applications that require higher levels of data integrity it is a recommended practice to use error correcting code (ecc) techniques. the nexflash serial flash development kit provides a software routine for a 32-bit ecc that can detect up to two bit errors and correct one. the ecc not only minimizes problems caused by system noise but can also extend flash memory endurance. write/verify flow for those systems without the processing power to handle ecc algorithms, a simple ? verification after write ? is recom- mended. the write verify can be done quickly (less than t xs ) using the compare sector command. the compare result can be checked in the status register. if compare is not equal (cne=1) then a sector rewrite should be done using the transfer to sector command (figure 12). a single retry is adequate for most applications. however, if an applica- tion requires extended endurance additional retrys can be added. the serial flash development kit software includes a simple write/verify routine that will compare data written to a given sector and rewrite the sector if the compare is not correct. no more retries no yes retry write verify return error write to sram command transfer sram to sector command compare sector with sram command ready? programming done? equivalent retry counter no yes figure 12. write/verify flow grouping static and frequently updated data in the nx25f011b/021b/041b a data block is every 32 sectors starting from sector 0; that is, block 0 is sector 0 - 31, block 1 is sector 32 - 63 and so on. refer to figure 4. for the highest data integrity, it is important to separate static data (configuration settings, tables) and frequently updated data (streaming voice/image or data acquisition) into separate blocks. following this convention optimizes the environment for the data stored in the flash cells within each block.
30 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b abosolute minimum ratings (1) symbol par ameters conditions range unit vcc supply voltage 0 to 7.0 v v in , v out voltage applied to any pin relative to ground ? 0.5 to vcc + 0.5 v t stg storage temperature ? 65 to +150 c t lead lead temperature soldering 10 seconds +300 c note: 1. this device has been designed and tested for the specified operation ranges. proper operation outside of these levels is not guaranteed. exposure beyond absolute maximum ratings (listed above) may cause permanent damage. operating ranges symbol parameter conditions min max unit vcc supply voltage (1) 5.0v programing 4.5 5.5 v 3.0v or 3.3 v programing 2.7 3.6 v t a ambient temperature, operating commercial 0 +70 c extended ? 20 +70 c industrial ? 40 +85 c t rvcc power ramp time ? 10 ms note: 1. vcc voltage during read can operate across the min and max range but should not exceed 10% of the programming (erase/write) voltage. dc electrical characteristics (preliminary) (2) symbol parameter conditions min typ max unit v il input low voltage ? 0.4 ? vccx0.2 v v ih input high voltage vccx0.6 ? vcc+0.5 v v ol output low voltage i ol = 2 ma v cc = 4.5v ?? 0.45 v v oh output high voltage i oh = ? 400 a v cc = 4.5v 2.4 ?? v v olc output low voltage cmos v cc = min, i ol = 10 a ?? 0.15 v v ohc output high voltage cmos v cc = min, i oh = ? 10 a v cc ? 0.3 ?? v i il input leakage 0 < v in < vcc ? 10 ? +10 a i ol i/o leakage 0 < v in < vcc ? 10 ? +10 a i cc active power supply current f clk @ 8 mhz (1/t cp )v cc = 5v 5 6 8 ma (active) v cc = 3v 2 2.5 4 ma i cclf active current low f clk @1 mhz (1/t cp )v cc = 5v 2 4 5 ma (low frequency. read v cc = 3v 1 1.5 2 ma frequency) i ccsb standby vcc supply current cs = v cc , vcc = 5v ? 510a (standby) v in = vcc or 0 vcc = 3v ? 15a c in input capacitance (1) t a = 25 c, v cc = 5v or 3v ?? 10 pf frequency = 1 mhz c out output capacitance (1) t a = 25 c, v cc = 5v or 3v ?? 10 pf frequency = 1 mhz notes: 1. tested on a sample basis or specified through design or characterization data. 2. see preliminary designation page 31
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 31 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 ac electrical characteristics (preliminary) (4) fast spi standard spi (rce =1) (rce = 0) symbol description min typ max min typ max unit f req clock frequency vcc = 5v 0 ? 20 0 ? 12 mhz vcc = 3v 0 ? 20 0 ? 10 mhz t cyc sck serial clock period (1) vcc = 5v 50 ?? 80 ?? ns vcc = 3v 50 ?? 100 ?? ns t wh sck serial clock high or low time 24 ?? 24 ?? ns t wl t ri sck serial clock rise or fall time (2) ?? 5 ?? 5ns t fi t su data input setup time to sclk vcc = 5v 14 ?? 14 ?? ns vcc = 3v 25 ?? 25 ?? ns t ih data input hold time from sclk 0 ?? 0 ?? ns t oh data output hold time from sclk 0 ?? 0 ?? ns t v data output valid after sclk (1,3) vcc = 5v ?? 35 ?? 35 ns vcc = 3v ?? 45 ?? 45 ns t css cs setup time to command 100 ?? 100 ?? ns t csh cs hold time after command 100 ?? 100 ?? ns t wp erase/write program time ? 7.5 20 ? 7.5 20 ms (see write to sector command) t eo erase only time ? 24 ? 24 ms (see erase sector/block commands) t wo write only time ? 5.5 16 ? 5.5 16 ms (see write only to sector command) t xs transfer or compare sector ? 100 150 ? 100 150 s (see transfer/compare all command) t hd sck setup time to hold 10 ?? 10 ?? ns t cd sck hold time from hold 30 ?? 30 ?? ns t cs cs deselect time 160 ?? 160 ?? ns t rb ready / busy valid time 160 ?? 160 ?? ns t dis data output disable time ?? 60 ?? 60 ns t hz data disable/enable from hold ?? 60 ?? 60 ns notes: 1. to achieve maximum clock performance, the read clock edge will need to be set for rising edge operation in the configuration register (rce=1). 2. test points are 10% and 90% points for rise/fall times. all others timings are measured at 50% point. 3. with 30 pf (16 mhz) load so to gnd. 4. see preliminary designation page 31
32 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b cs sck so lsb lsb+1 msb-1 msb si t v t cyc t oh t wl t wh t csh t dis serial output timing serial input timing (high impedance) t ih msb msb-1 lsb lsb+1 t css t csh t cs t rb t su t xs t wp t ri t fi cs r/ b sck si so cs hold sck so si t hd t cd t hd t cd t hz t hz hold timing
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 33 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 packaging information 200-mil plastic soic package code: (s) n 1 d e h a seating plane a1 l a c e b 200 mil plastic soic (s) millimeters inches symbol min max min max no. leads 8 a 1.780 2.030 0.070 0.080 a1 0.102 0.330 0.004 0.013 b 0.305 0.508 0.012 0.020 c 0.178 0.254 0.007 0.010 d 5.160 5.380 0.203 0.212 e 5.210 5.410 0.205 0.213 e 1.27bsc 0.050 bsc h 7.62 8.38 0.300 0.330 l 0.508 0.889 0.020 0.035 0 o 8 o 0 o 8 o notes: 1. controlling dimensions: inches, unless otherwise specified. 2. bsc = basic lead spacing between centers. 3. dimensions d and e1 do not include mold flash protrusions and should be measured from the bottom of the package. 4. formed leads shall be planar with respect to one another within .0004 inches at the seating plane.
34 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b d seating plane b e c 1 e a1 h l n a 330 mil plastic soic (j) millimeters inches symbol min max min max ref. std. no. leads 28 a 2.388 2.794 0.094 0.110 a1 0.051 0.508 0.002 0.020 b 0.051 0.356 0.002 0.014 c 0.203 0.305 0.008 0.0012 d 7.983 8.288 0.709 0.720 e 8.585 8.788 0.338 0.346 h 11.68 12.19 0.460 0.480 e 1.27 bsc 0.050 bsc l 0.762 1.270 0.030 0.050 a0 8 0 8 notes: 1. controlling dimension: inches, unless otherwise specified. 2. bsc = basic lead spacing between centers. 3. dimensions d and e do not include mold flash protrusions and should be measured from the bottom of the package. 4. formed leads shall be planar with respect to one another within 0.004 inches at the seating plane. packaging information 330 mil plastic soic package code: (j)
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 35 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12 notes: 1. controlling dimension: millimeters, unless otherwise specified. 2. bsc = basic lead spacing between centers. 3. dimensions d and e do not include mold flash protrusions and should be measured from the bottom of the package . 4. formed leads shall be planar with respect to one another within 0.004 inches at the seating plane. d seating plane b e c 1 e a1 h l n a packaging information plastic tsop - 28-pins package code: type i (v) plastic tsop type i (v) millimeters inches symbol min max min max no. leads 28 a 1.00 1.20 0.039 0.047 a1 0.05 0.20 0.002 0.008 b 0.15 0.25 0.006 0.010 c 0.10 0.20 0.004 0.008 d 7.90 8.10 0.311 0.319 e 11.60 11.80 0.457 0.465 h 13.30 13.50 0.524 0.531 e 0.55 bsc 0.022 bsc l 0.50 0.70 0.020 0.028 0 5 0 5
36 nexflash technologies, inc. preliminary nxsf016f-1201 12/12/01 ? nx25f011b NX25F021B nx25f041b preliminary designation the ? preliminary ? designation on an nexflash data sheet indicates that the product is not fully characterized. the specifications are subject to change and are not guaran- teed. nexflash or an authorized sales representative should be consulted for current information before using this product. important notice nexflash reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. nexflash assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. charts and schedules contained herein re- flect representative operating parameters, and may vary depending upon a user ? s specific application. while the information in this publication has been carefully checked, nexflash shall not be liable for any damages arising as a result of any error or omission. life support policy nexflash does not recommend the use of any of it's products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure in the life support system or to significantly affect its safety or effectiveness. products are not authorized for use in such applications unless nexflash receives written assurances, to it ? s satisfaction, that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; and (c) potential liability of nexflash is adequately pro- tected under the circumstances. trademarks: nexflash is a trademark of nexflash technologies, inc . all other marks are the property of their respective owner. ordering information size order part no. package 1m-bit nx25f011b-3v* spi, 28-pin, tsop (type i)3v 1m-bit nx25f011b-3s* spi, 8-pin, soic 3v 1m-bit nx25f011b-5v* spi, 28-pin, tsop (type i) 5v 1m-bit nx25f011b-5s* spi, 8-pin, soic 5v 2m-bit NX25F021B-3v* spi, 28-pin, tsop (type i) 3v 2m-bit NX25F021B-3s* spi, 8-pin, soic 3v 2m-bit NX25F021B-5v* spi, 28-pin, tsop (type i) 5v 2m-bit NX25F021B-5s* spi, 8-pin, soic 5v 4m-bit nx25f041b-3v* spi, 28-pin, tsop (type i) 3v 4m-bit nx25f041b-3j spi, 28-pin, soic 3v 4m-bit nx25f041b-5v* spi, 28-pin, tsop (type i) 5v 4m-bit nx25f041b-5j spi, 28-pin, soic 5v *note: add -r for restricted sector device (see serial flash application note sfan-2 for more information on restricted sector devices).
nx25f011b NX25F021B nx25f041b nexflash technologies, inc. 37 preliminary nxsf016f-1201 12/12/01 ? 1 2 3 4 5 6 7 8 9 10 11 12

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