IBM 770 User Manual
Bit 7
This read-only bit monitors the internal battery. If set to
1, this bit indicates that the real-time clock has power. If
set to 0, it indicates that the real-time clock has lost
power and the data in CMOS is no longer valid.
1, this bit indicates that the real-time clock has power. If
set to 0, it indicates that the real-time clock has lost
power and the data in CMOS is no longer valid.
Bits 6–0
These bits are reserved.
CMOS RAM Configuration
Figure 2-20 shows the bit definitions for the CMOS RAM
configuration bytes.
configuration bytes.
Diagnostic Status Byte (Hex 00E)
Figure
2-20. Diagnostic Status Byte (Hex 00E)
Bit
Function
7
Real-time clock power
6
Configuration record and checksum status
5
Incorrect configuration
4
Memory size mismatch
3
Hard disk controller/drive C initialization status
2
Time status indicator
1, 0
Reserved
Bit 7
If set to 1, this bit indicates that the real-time clock has
lost power.
lost power.
Bit 6
If set to 1, this bit indicates that the checksum is incorrect.
Bit 5
This bit indicates the results of a power-on check of the
equipment byte (hex 014). If set to 1, this bit indicates
that the configuration information is incorrect.
equipment byte (hex 014). If set to 1, this bit indicates
that the configuration information is incorrect.
Bit 4
If set to 1, this bit indicates that the memory size does not
match the configuration information.
match the configuration information.
Bit 3
If set to 1, this bit indicates that the controller or hard disk
drive failed initialization.
drive failed initialization.
Bit 2
If set to 1, this bit indicates that the time is invalid.
Bits 1, 0
These bits are reserved.
Shutdown Status Byte (Hex 00F): This byte is defined by the
power-on diagnostic programs.
power-on diagnostic programs.
System Board
2-25