System Installation
RUBY-7720VG2A User’s Manual
3-6
Time-out Value to be counted down to zero. Users can directly fill a zero value into
CR_T
wd
to disable WDT immediately. To ensure a successful access to the desired
Control Register, the following programming guide should be followed.
Programming guide:
CR: Configuration Register.
LD: Logical Device of SIO. There are 11 LDs in W83627HG SIO.
CR00~2F: Global Control Registers. (All LDs share these CRs )
CR07: LD selection.
CR30~FF: Each LD has its own CR30~FF.
There are two I/O ports as I/O access window for configuring WDT,
1) IO port 0x2E is H/W strapped and named as EFIR (Extended Function Index
Register, for identifying CR index number)
2) IO port 0x2F is H/W strapped and named as EFDR (Extended Function Data
Register, for accessing desired CR)
<< How to access W83627HG Configuration Register >>
First, it needs to enter extended function mode.
Enter extended function mode for accessing W83627HG configuration registers:
outportb(EFIR, 0x87);
outportb(EFIR, 0x87);
// double IO write
Read Configuration Register CR_rx, and keep this byte to unsigned char al_char
outportb(EFIR, CR_rx ) ;
al_char = inportb(EFDR) ;
Write Configuration Register CR_wx with byte al_char1 ;
outportb(EFIR, CR_wx ) ;
outportb(EFDR, al_char1);
Exit extended mode after completion of configuration register access.
outportb(EFIR, 0xaa);
