AAEON PCM-QM77 - Manual (Page 171)

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-8
out dx, al
mov dx, 0f040h + 05h
mov al, ah
out dx, al
mov dx, 0f040h + 00h ; Host Control Register
mov al, 48h ; Start a byte access
out dx, al
call CT_Chk_SMBus_Ready
ret
Ct_I2CWriteByte Endp
; Wait until the busy bit clears, indicating that the SMBUS
; activity has concluded.
CT_Chk_SMBus_Ready Proc Near
mov dx,0f040h+ 0;status port
clc
mov cx,0800h
Chk_I2c_OK:
in al,dx ;get status
call Delay5ms