AAEON PCM-QM77 - Manual (Page 170)

C o m p a c t B o a r d P C M - Q M 7 7
Appendix E Digital I/O F-7
Ct_I2CReadByte Endp
;Input : CL - register index
; CH - device ID
; AL - Value to write
;Output: none
Ct_I2CWriteByte Proc Near
mov ch,06eh
xchg ah, al
mov dx, 0f040h + 00h ; Host Control Register
mov al, 0ffh ; Clear previous
commands
out dx, al
call Delay5ms
mov dx, 0f040h + 04h ; Transmit Slave Address
Register
mov al, ch ; Set the slave address and
out dx, al ; prepare for a WRITE
command
mov dx, 0f040h + 03h ; Host Command Register
mov al, cl ; offset to write