Watchdog Timer - MSI MS-9892 Manual

Watchdog Timer

2. Watchdog Timer – WDT
The base address (WDT_BASE) of WDT configuration registers is 0xA10.
2.1 Set WDT Time Unit
val = Inportb (WDT_BASE + 0x05);
val = val | 0x08;
Outportb (WDT_BASE + 0x05, val);
2.2 Set WDT Time
Outportb (WDT_BASE + 0x06, Time);
2.3 Enable WDT
val = Inportb (WDT_BASE + 0x0A);
val = val | 0x01;
Outportb (WDT_BASE + 0x0A, val);
val = Inportb (WDT_BASE + 0x05);
val = val | 0x20;
Outportb (WDT_BASE + 0x05, val);
2.4 Disable WDT
val = Inportb (WDT_BASE + 0x05);
val = val & 0xDF;
Outportb (WDT_BASE + 0x05, val);
2.5 Check WDT Reset Flag
If the system has been reset by WDT function, this flag will set to 1.
val = Inportb (WDT_BASE + 0x05);
val = val & 0x40;
if (val) printf ("timeout event occurred");
else printf ("timeout event not occurred");
2.6 Clear WDT Reset Flag
val = Inportb (WDT_BASE + 0x05);
val = val | 0x40;
Outportb (WDT_BASE + 0x05, val);
// Read current WDT setting
// minute mode. val = val & 0xF7 if second mode
// Write back WDT setting
// Write WDT time, value 1 to 255.
// Read current WDT_PME setting
// Enable WDT OUT: WDOUT_EN (bit 0) set to 1.
// Write back WDT setting.
// Read current WDT setting
// Enable WDT by set WD_EN (bit 5) to 1.
// Write back WDT setting.
// Read current WDT setting
// Disable WDT by set WD_EN (bit 5) to 0.
// Write back WDT setting.
// Read current WDT setting.
// Check WDTMOUT_STS (bit 6).
// Read current WDT setting
// Set 1 to WDTMOUT_STS (bit 6);
// Write back WDT setting
MS-9892
A-5