rtd CMV6486DX100HR, User Manual

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When you perform simple EEPROM read operations, you do not need to enable the EEPROM and
can use the BIOS read command (function 2) directly.
When you perform EEPROM write operations, you must perform a correct write cycle as follows:
• enable the EEPROM
• erase the relevant locations
• write the relevant locations
• disable the EEPROM
• verify that the write operation has been correctly performed
INPUTS: AH = 3
AL = word address (20H-3FH accepted)
CX = number of words to read
DS:SI = pointer to the buffer where the read values are stored
RETURNS: AH = error code; if AH<>0, then AL = number of locations writ-
ten
Function 4 EEPROM verify. Verifies that the values contained in the device
at the address specified by AL, for the number of words specified
in CX, match the values in the buffer pointed to by ES:DI
INPUTS: AH = 4
AL = word address (0-3FH accepted)
CX = number of words to read
ES:DI = pointer to the buffer where the read values are stored
RETURNS: AH=error code
if AH = FF, then AL = address where the compare failed
Function 5 EEPROM Erase. Erases words, starting from the address specified
in AL, for the length specified in CX
INPUTS: AH = 5
AL = word address 20H-3FH accepted)
CX = number of words to read
RETURNS: AH = error code; if AH<> 0, then AL= number of locations erased
Error codes Errors detected by interrupt 52H are returned in register AH with
the following code:
register AH: 00H no errors
10H access attempted to locations reserved by the BIOS
20H invalid address
40H illegal command
80H time-out
FFH error in verify procedure