Advantech ITA-5831 Series, User Manual

Page: 79 / 96

69 ITA-5831 User Manual
Chapter 6
G
PIO Programming
Guide
Function Call for Reference
......................................................................................................................................
ICH SMBUS Access Code
(The following code is realized by simulating the access of BIOS to
SMBUS. It uses Borland C++.
3.1 for compiling and is successfully tested under DOS (But it is not
tested under other OSs).
#define SMBUS_PORT 0xF040 //SMB_BASE is 0xF040
typedefunsigned char BYTE;
/////////////////////////////////////////////////////////////////////
BYTE smbus_read_byte(BYTE addr, BYTE offset)
//Read SMBUS Register byte value. Read one byte value each time. ddr
is slave
address (such as 0x40), and offset is register offset.
{
int i;
BYTE data;
outportb(SMBU 4, (addr | 1)); //Write slave address to
SM 4 (When reading, bit 0 of slave address should be set as 1,
so here addr|1 is available)
newiodelay(); //delay
newiodelay(); //delay
chk_smbus_ready(); //Whether SMBUS is ready
outportb(SMBU 3, offset);//Write register offset to
SMB_BASE +3.
newiodelay(); //delay
newiodelay(); //delay
outportb(SMBU 2, 0x48); //Write SMBUS command to
SM 2. 0x48 means starting byte data transmission
newiodelay(); //delay
newiodelay(); //delay
for (i = 0; i <= 0x100; i++)
{
newiodelay(); //longerdelay
}