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AN1259 APPLICATION NOTE
M8813F2Y FLASH+PSD and M48T35Y TIMEKEEPER Demonstration
FLASH+PSD, from STMicroelectronics, is a family of Flash memory based programmable system devices (PSDs) for 8 bit micro-controllers. The M8813F2Y-90K1 is an 8-bit FLASH+PSD with 128Kx8 bit of primary Flash memory, 8Kx8 bit of secondary boot Flash memory, 2Kx8 bit of SRAM, 27 I/O port pins, and a JTAG interface for in system programming (ISP). The 80C32-based M8DK8051 Evaluation Board, shown in Figure 1, illustrates the versatility of the FLASH+PSD. For example, it illustrates its extensibility to include extra battery backed SRAM, and a real time clock (RTC), in its address space. This has been added in the form of a 32KX8 bit CMOS TIMEKEEPER SRAM, the M48T35Y-70PC1. This has an on-chip RTC, which allows the time of day to be read continuously out to the liquid crystal display on the evaluation board. This document describes how this can be achieved. Figure 1. Layout of the 80C32-based M8DK8051-K52-110 Evaluation Board
P4
Serial Port Prototype Area
9V Battery Holder
U5
P3
P5
NORMAL MEAS ma MEAS uA
on off S3 JP1 TP1
INT EXT JP4
M48T35
TIMEKEEPER
P2
connector, OPC1
U3
U2 JTAG NO JTAG
JP2
80C32 MCU
P1
M8813F2Y
no chain chain
TP_GND 1 TP_PS JTAG, P2
1
JP3
JTAG, P1
JP1 CSI non-active CSI active psd JP3rst rst supv DS3 DS2 S2 Reset S1
LCD Display
connector, OPC2
AI03762
March 2000
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AN1259 - APPLICATION NOTE
The evaluation board is delivered with C code already embedded. This can be modified, as described next. First, a file can be created, called timekeeper.h, in which to define the following variables and a function prototype: uchar uchar uchar uchar uchar uchar uchar uchar void xdata myear _at_ 0x7fff; xdata mmonth _at_ 0x7ffe; xdata mdate _at_ 0x7ffd; xdata mday _at_ 0x7ffc; xdata mhour _at_ 0x7ffb; xdata mminutes _at_ 0x7ffa; xdata mseconds _at_ 0x7ff9; xdata mcontrol _at_ 0x7ff8; gettimekeeper(void);
The data type xdata is one that the Keil C compiler recognizes for the 80C31. It stands for external data. The variables are defined for the registers of the M48T35 (as shown in Table 1) and are used in the gettimekeeper() function. Table 1. M48T35 Register Map
Data Address D7 7FFFh 7FFEh 7FFDh 7FFCh 7FFBh 7FFAh 7FF9h 7FF8h
Notes: 1. 2. 3. 4. 5. 6.
Function D6 D5 D4 D3 D2 Year 10M 10 Date 0 0 0 Month Date Day Hours 10 Minutes Seconds Calibration D1 D0 Year Month Date Day Hour Minute Second Control 10 Years 0 0 0 0 0 ST W R 0 0 FT 0 0
Range (in BCD Format) 00-99 01-12 01-31 01-7 00-23 00-59 00-59
10 Hours 10 Minutes 10 Seconds S
S = Sign bit FT = Frequency Test bit (must be reset to 0 for normal clock operation when powered-up R = Read bit W = Write bit ST = Stop bit 0 = must be reset to 0
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The first code fragment was added to evaltest.c: lcd_clear(); lcd_string_display(0,0,"The time is:"); while(1) { gettimekeeper(); } The LCD is a 2x16 character display. It accepts and displays ASCII characters. The lcd_clear() function clears the display by writing the space character (0x20h) to all 32 locations of the LCD display, and is already supplied with the source code for the board. The function lcd_string_display(0,0,"The time is:"); writes "The time is:" to the first line of the display at the first position. The program then goes into an infinite loop in which the function gettimekeeper(), to get and display the time, is called over and over again. This infinite loop gives the display the appearance of a digital clock. The next code fragment defines the function gettimekeeper(), and can be added to the other functions in evl_io.c: void gettimekeeper(void) { uchar chr; chr=(mhour&0xf0)/0x10|0x30; lcd_char_display(1,0,chr); chr=(mhour&0x0f)|0x30; lcd_char_display(1,1,chr); lcd_char_display(1,2, ':' ); chr=(mminutes&0xf0)/0x10|0x30; lcd_char_display(1,3,chr); chr=(mminutes&0x0f)|0x30; lcd_char_display(1,4,chr); lcd_char_display(1,5, ':' ); chr=(mseconds&0xf0)/0x10|0x30; lcd_char_display(1,6,chr); chr=(mseconds&0x0f)|0x30; lcd_char_display(1,7,chr); } This routine reads the TIMEKEEPER registers, converts the values to ASCII characters, ready to be sent to the appropriate position on the LCD display. For example, the first line of this function reads the hour byte from location 0x7FFBh. This byte contains the hour of the day, which consists of two binary coded decimal digits in the upper and lower nibbles of the byte. The first digit is converted to an ASCII character by ANDing it with 0xF0. The data is then shifted right four places by dividing the byte by 16 (0x10). Finally the byte is ORed with 0x30 to form the ASCII byte to be sent to the display. The lower nibble is converted
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to ASCII in the same way except it is masked, by ANDing it with 0x0F, and does not need any shifting right. After each conversion, the byte is sent to the bottom row of the display in the right position using the lcd_char_display() function that comes with the source for the board. The remaining digits are sent to the display in the same manner. The colons ( : ) are sent to the display to give the format of the time the correct appearance. Figure 2 shows the memory map for this application. The program is stored in, and executed from, CSBOOT0. Figure 2. Memory Map for the 80C32
Program Memory
FFFF
Data Memory
E000
FS7 16 KByte
C000
A000
External SRAM 16 KByte
Devices
4B00
LCD
4A00
8000
PSD RAM 2 KByte
4200
CSIOP regs
4100 4000
CSBOOT1 8 KByte
2000
CSBOOT0 8 KByte
0000
80C32 boots from here
AI03761
There is one additional change that needs to be made to the abel file. The SRAM registers are based at 0x7FF0 in the C code. This means they must be mapped into the address space in the abel file for the project. This can be achieved by adding a term to the chip select (cs_ram) equation in the abel file. Appearance of the equation before the change has been made: cs_ram_ = ((address >= ^h0000) & (address <= ^h3FFF) & (page == X) & !es0 & es1 ) #( (address >= ^h8000) & (address <= ^hBFFF) & (page == X)& !(!es0 & es1 ) ) Appearance of the equation after the change has been made: cs_ram_ = ((address >= ^h0000) & (address <= ^h3FFF) & (page == X) & !es0 & es1 ) #( (address >= ^h8000) & (address <= ^hBFFF) & (page == X)& !(!es0 & es1 ) ) #( (address >= ^h7FF0) & (address <= ^h7FFF) & (page == X));
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For current information on M88 FLASH+PSD products, please consult our pages on the world wide web: www.st.com/flashpsd If you have any questions or suggestions concerning the matters raised in this document, please send them to the following electronic mail addresses:
apps.flashpsd@st.com apps.nvram@st.com ask.memory@st.com
(for application support on FLASH+PSD) (for application support on TIMEKEEPER) (for general enquiries)
Please remember to include your name, company, location, telephone number and fax number.
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express writt en approval of STMicroelectronics. (c) 2000 STMicroelectronics - All Rights Reserved The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain Sweden - Switzerland - United Kingdom - U.S.A. http:// www.st.com
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