Battery Status Register (Read Only) - Siemens SIMATIC IPC PX-39A Operating Instructions Manual

Hardware description
A.5 System resources
A.5.2.2

Battery status register (read only)

The status of the CMOS battery (two levels) can be read out via the battery status register as
follows.
Note: Always use read-modify-write operations so that reserved bits are not overwritten. This
can lead to impairment of the functionality of the device.
Procedure
1. Write 06h into the GPIO port select register (280h) to select the relevant register (GPIO6).
2. To get information about the battery status, read the desired value from the GPIO6 data
register (282h).
Meaning of the bits
Battery status register (read, address 282h)
Bits
7
x
112
6 5 4 3
0 0
0 1
1 1
x
x
Meaning of the bits
2 1 0
x Reserved
x Reserved
x Reserved
CMOS battery capacity is still sufficient
CMOS battery capacity is exhausted (remain-
ing capacity is still sufficient for approx. 1
month)
CMOS battery is empty or missing
Reserved
Reserved
Reserved
Operating Instructions, 08/2022, A5E51699601-AA
SIMATIC IPC PX-39A