Technical specifications
7.5 Hardware descriptions
SIMATIC IPC327G
Operating Instructions, 09/2021, A5E51366275-AA
73
7.5.5.3
Watchdog counter register
Bit
Read/Write
state
Meaning of the bits
0 to 7
Read/Write
Watch Dog Timer I Time-out value. Writing a non-zero value to the regis-
ter causes the counter to load the value into the Watch Dog Counter and
start counting down. The accuracy of watchdog timer I about one cycle
deviation. Non-zero value will be reloaded to the Watch Dog Counter and
the countdown resumes. Reading the register returns the current value in
the Watch Dog Counter but not the Watch Dog Timer Time-out value.
•
00h: Time-out Disable
•
01h: Time-out occurs after one cycle time, the cycle time is based on
LD8 CRF0, bit[3], by analogy.
7.5.5.4
Watchdog state register
Bit
Read/Write
state
Meaning of the bits
7
Read/Write
Not used for watchdog
6
Read/Write
Not used for watchdog
5
Write "1" Only Trigger Watchdog Timer I event. This bit is self-clearing.
4
Read/Write
Watchdog Timer I status bit:
•
0: Watchdog Timer I is running.
•
1: Watchdog Timer I issues time-out event.
3 to 0
Read/Write
Not used for watchdog
7.5.5.5
Battery status register
The status of the CMOS battery is monitored; the status (two-tier) can be read from the
battery status register.
Meaning of the bits
Battery status register (read-only, address 404Dh)
Bit
Meaning
7
6
5
4
3
2
1
0
0 0
CMOS battery capacity is still sufficient.
0 1
CMOS battery capacity is exhausted (remaining capacity is suffi-
cient for approx. one month)
1 1
CMOS battery is empty
