User manual

SOM-5786 User Manual 34
A.1 Programming the Watchdog Timer
1. SMBus Address: Pin 3 internal pull up 100K = 0X9C, External pull up 4.7K =
0X6E2.
2. Enable WDT function: Configuration and function select register Index-03h3.
3. Watchdog Control: Watchdog Timer Control Register - Index 36h
Power-on default [7:0] =0000_0000b
4. Watchdog reset timing control: Watchdog Timer Range Register - Index 37h
Power-on default [7:0] =0000_0000b
Table A.1: Index-03h
Bit Name P/W PWR Description
1-0 PIN10_MODE R/W VSB3V 00:GPI010 01: LED10 IN this mode can use
REG Ox06(bit1,0) to select LED frequency.
10,11 :WD_OUT
Table A.2: Watchdog Timer Index 36h
Bit Name P/W PWR Description
7 Reserved RO VSB3V Reserved. Read will return 0.
6 STS WD TMOUT R/W VSB3V Watchdog is timeout. When the watchdog is
timeout, this bit will be set to one. If set to 1,
write 1 will clear this bit. Write 0, no effect.
5 WD ENABLE R/W VSB3V Enable watchdog timer.
4 WD PULSE R/W VSB3V Watchdog output level or pulse. If set 0
(default), the pin of watchdog is level output, if
write 1, the pin will output with a pulse.
3 WD UNIT R/W VSB3V Watchdog unit select. Default 0 is select sec-
ond. Write 1 to select minute.
2 WD HAC-TIVE RW VSB3V Program WD2 output level. If set to 1 and
watchdog asserted, the pin will be high. If set to
0 and watchdog asserted, this pin will drive low
(default).
1-0 WD_PS WIDTH RW VSB3V Watchdog pulse width selection. If the pin out-
put is selected to pulse mode. The pulse width
can be choice.
00b- 1m second.
01b- 20m second.
10b -100m second.
11b- 4 second.
Table A.3: Watchdog Timer Range - Index 37h
Bit Name P/W PWR Description
7-0 WD_TIME RW VSB3V Watchdog timing range from 0 - 255. The unit is
either second or minute programmed by the
watchdog timer control register bits.