- 1 - in the absence of confirmation by device specification sheets, sharp takes no responsibility for any defects that may occur in equipment using any sharp devices shown in catalogs, data books, etc. contact sharp in order to obtain the latest device specification sheets before using any sharp device. SM3508 description the SM3508 is a cmos 4-bit single-chip micro- computer for databank incorporating data memory ram, lcd driver (the output is adjustable in 16 steps for various contrast), key/switch input circuit, 8-bit parallel i/o port, 2 output ports and buzzer output circuit. the chip also has memory expansion controlling feature. one of two ports contains spe- cial output circuit for infrared (ir) communication. by connecting an external crystal, a 1 hz timer is made possible for easier clock function. features ?rom capacity : program rom 12 k x 23 bits character rom 6 x 8 x 256 bits constant rom 1 k x 4 bits ?ram capacity : working ram 256 x 4 bits display ram 74 x 16 bits data ram 3 k x 8 bits ?memory expansion (external) : 1m x 8 bits x 3 ?lcd display : 74-segment x 16-common ?i/o ports : parallel i/o 8 bits input 2 bits output 2 bits buzzer output 1 bit (4 khz) key input 6 bits ?standby release : 2 events (2 hz signal, key input) ?built-in oscillator : ?instruction cycle time : 3 s ?operating temperature : ?0 to + 60? ?supply voltage : 2.5 to 5.5 v ?package : 128-pin qfp (qfp128-p-2828) [test sample only] SM3508 4-bit single-chip microcomputer (for data bank use) system clock (built-in cr oscillator) 1 mhz (external ceramic resonator) 1 mhz timer (built-in cr oscillator) 32.8 khz (external crystal) 32.768 khz
- 2 - SM3508 system comfiguration example key matrix expand memory 1 m-byte x 3 s 1 -s 8 s 9 -s 28 s 67 -s 74 (max. 112-key) s 1 -s 74 ce 1 -ce 3 ki 1 -ki 7 dio 1 -dio 8 rw ce ki 8 v cc test cci cco reset cxi cxo bz h 1 -h 16 eo 2 v h v 1 v 2 v 3 v 4 infrared signal for ir communication v cc v cc buzzer v cc SM3508 reset key 5v sw (high end data bank) common signal segment signal + v cc
SM3508 - 3 - 0.3 28.0 typ. 0.8 0.15 0.05 65 0.1 0.38 0.2 3.45 0.1 1 97 96 32 33 64 128 (1.6) 31.2 0.5 (1.6) 28.0 31.2 0.3 0.5 (1.6) (1.6) 0.1 1.65 (29.6) 0.15 0.15 m package base plane 128 qfp (qfp128-p-2828)
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