Siemens SIMATIC IPC277G - Watchdog State Register; Battery Status Register; NVRAM Address Register

Technical specifications
8.5 Hardware descriptions
SIMATIC IPC277G
100 Operating Instructions, 08/2021, A5E50059956-AA
8.5.5.4 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
8.5.5.5 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
sufficient for approx. one month)
1
1
CMOS battery is empty
8.5.5.6 NVRAM address register
NVRAM occupies a 512 KB memory address area that can be read via PCI registers.
Meaning of the bits
NVRAM address register
PCI register address:
NVRAM base address register
PCI register content:
NVRAM memory address (default
setting)
Length of the memory area
Address variable (depending
on the slot where NVRAM is
located)
Address is assigned dynamically
(depending on device
configuration)
80000 h