Advantech ITA-1611 Series, User Manual

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53 ITA-1611 User Manual
Chapter 6
G
PIO Programming
Guide
chk_smbus_ready(); //Determine if SMBUS is ready
outportb(SMBU 3, offset); //write register offset to SM 3
moredelay(); //long time delay
moredelay(); //long time delay
outportb(SMBU 5, value); //Write data value to SM 5
moredelay(); //long time delay
moredelay(); //long time delay
outportb(SMBU 2, 0x48); //Write SMBUS command to SM
2, 0x48 means starting Byte data transmission
moredelay(); //long time delay
moredelay(); //long time delay
for (i = 0; i <= 0x100; i++)
{
newiodelay(); //long time delay
}
chk_smbus_ready(); //Determine if SMBUS is ready
}
////////////////////////////////////////////////////////////////////////////////////////////////////
/
int chk_smbus_ready()
//Determine if SMBUS is ready or finished. Basically, it will wait for a long time to
see whether SMBUS has finished the transmission command because errors
hardly occur. So, in SMBUS byte read and write, BIOS Code does not determine
the return value of this function
{
int i, result = 1;
BYTE data;
for (i = 0; i <= 0x800; i++)
{
//SM 0 is SMBUS status value
data = inportb(SMBUS_PORT); //Read SMBUS status value once
data = check_data(SMBUS_PORT); //Read SMBUS status value several
times
outportb(SMBUS_PORT, data);//Write back SMBUS status value which
means clear status value(Write 1 to the corresponding bit will clear status)
if (data & 0x02)
{
//If bit 1 is set to 1 (this means the command is finished), then
SMBUS is ready
result = 0; //SMBUS ready
break;
}
if (!(data & 0xBF))
{
//If each bit except bit 2 is set to 0, this means SMBUS error , then
SMBUS is ready
result = 0; //SMBUS ready
break;