Octagon PC-510, User Manual

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17-2
Serial EEPROM and CMOS RAM PC-510 user’s manual
Return registers: Carry flag cleared if successful
AX Word read
Carry flag set if error
AL Error code
Error code Meaning
ffh
Unknown error
01h Function not implemented
02h Defective serial EEPROM
03h Illegal access
Comments: This function reads a word from the user area of the
serial EEPROM.
Programming example:
/* Read word 2 */
unsigned int seeData;
/* Inline assembly code for Borland C++ 3.1 */
asm {
mov
ax,0fc00h
mov bx,02h /* Read word 2 */
mov dx,0ffffh
int 17h
mov seeData,ax /* store data in c environment */
}
Write a single word to the serial EEPROM
Function: fch
Subfunction: 01h
Purpose: To write a single word to the on-board serial
EEPROM.
Calling registers: AH fch
AL 01h
BX Word address (zero based)
CX Data word to write
DX ffffh (relative to user area)
Return registers: Carry flag cleared if successful
Carry flag set if error
AL Error code
Error code Meaning
ffh
Unknown error
01h Function not implemented
02h Defective serial EEPROM
03h Illegal access
Comments: This function writes a word to the user area of the
serial EEPROM.