Specifications

Page A3

Appendix B: Programming

the Watchdog Timer

Programming the timer requires entry into the 82360SL configuration space. This

configuration space is enabled by performing four sequential reads to the following

I/O addresses : 0FC23H, 0F023h, 0C023h and 0023h. When enabled access to the

registers within is controlled by two 8-bit read/write registers: the Configuration

Index Register, CFGINDEX (24h) and the Configuration Data Register, CFGDATA

(25h). The CFGINDEX register stores the index of the register to be accessed and

the CFGDATA register stores the data.

The code segment below is a Microsoft C for DOS example of how to enable the

82360SL configuration space:

unsigned short

saveflags()

{

unsigned short flags;

ASM

pushf

pop flags

ENDASM

return flags;

}

unsigned short

enablespace()

{

unsigned short flags;

flags = saveflags();

_disable();

(void) inp(0xFC23);

(void) inp(0xF023);

(void) inp(0xC023);

(void) inp(0x0023);

return flags;

}