Portwell WADE-8075, User Manual

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System Installation
WADE-8075 / WADE-8076 User’s Manual 3-4
The related Control Registers of WDT are all included in the following sample
program that is written in C language. User can fill a non-zero value into the
Time-out Value Register to enable/refresh WDT. System will be reset after the
Time-out Value to be counted down to zero. Or user can directly fill a zero value into
Time-out Value Register to disable WDT immediately. To ensure a successful
accessing to the content of desired Control Register, the sequence of following
program codes should be step-by-step run again when each register is accessed.
Additionally, there are maximum 2 seconds of counting tolerance that should be
considered into user’ application program. For more information about WDT, please
refer to Winbond W83627UHG data sheet.
There are two PNP I/O port addresses that can be used to configure WDT,
1) 0x2E:EFIR (Extended Function Index Register, for identifying CR index number)
2) 0x2F:EFDR (Extended Function Data Register, for accessing desired CR)
WDT Control Command Example
// Enter Extended Function Mode
outp(0x002E, 0x87);
outp(0x002E, 0x87);
// Enable Pin 77 as WDTO#
// Select Logic Device 8
outp(0x002E, 0x07);
outp(0x002F, 0x08);
// Active Logic Device 8
outp(0x002E, 0x30);
outp(0x002F, 0x01);
// Select Count Mode
outp(0x002E, 0xF5);
outp(0x002F, (inp(0x002F) & 0xF7) | (
Count-mode Register & 0x08));
// Specify Time-out Value
outp(0x002E, 0xF6);
outp(0x002F,
Time-out Value Register );
// Disable WDT reset by keyboard/mouse interrupts
outp(0x002E, 0xF7);
outp(0x002F, 0x00);
// Exit Extended Function Mode
outp(0x002E, 0xAA);