MSI 939-9A79-002, Руководство пользователя, Страница: 72 / 72

A-6
GPIO WDT BKL Programming MS-9A79
SMBus Access
4. SMBus Access
The base address of SMBus must be known before access. The relevant bus and device
information are as following.
#define IO_SC 0xCF8
#define IO_DA 0xCFC
#define PCIBASEADDRESS 0x80000000
#define PCI_BUS_NUM 0
#define PCI_DEV_NUM 31
#define PCI_FUN_NUM 1
4.1 Get SMBus Base Address
int SMBUS_BASE;
int DATA_ADDR = PCIBASEADDRESS + (PCI_BUS_NUM<<16) +
(PCI_DEV_NUM<<11) +
(PCI_FUN_NUM<<8);
Outportl
(DATA_ADDR + 0x20, IO_SC);
SMBUS_BASE =
Inportl
(IO_DA) & 0xfffffff0;
4.2 SMBus_ReadByte (char DEVID, char offset)
Read the value of OFFSET from SMBus device DEVID.
Outportb (LOWORD (SMBUS_BASE), 0xFE);
Outportb (LOWORD (SMBUS_BASE) + 0x04, DEVID + 1); //out Base + 04, (DEVID + 1)
Outportb (LOWORD (SMBUS_BASE) + 0x03, OFFSET); //out Base + 03, OFFSET
Outportb (LOWORD (SMBUS_BASE) + 0x02, 0x48); //out Base + 02, 48H
mdelay (20); //delay 20ms to let data ready
while ((Inportl (SMBUS_BASE) & 0x01) != 0); //wait SMBus ready
SMB
_DATA = Inportb (LOWORD (SMBUS_BASE) + 0x05); //input Base + 05
4.3 SMBus_WriteByte (char DEVID, char offset, char DATA)
Write DATA to OFFSET on SMBus device DEVID.
Outportb (LOWORD (SMBUS_BASE), 0xFE);
Outportb (LOWORD (SMBUS_BASE) + 0x04, DEVID); //out Base + 04, (DEVID)
Outportb (LOWORD (SMBUS_BASE) + 0x03, OFFSET); //out Base + 03, OFFSET
Outportb (LOWORD (SMBUS_BASE) + 0x05, DATA); //out Base + 05, DATA
Outportb (LOWORD (SMBUS_BASE) + 0x02, 0x48); //out Base + 02, 48H
mdelay (20); //wait 20ms