IBM CMX58886CX user manual Reset Status Register, Reset Status I/O Address 457h Read Access

Reset Status Register

The cpuModule has several different signals on board which can cause a system reset. If a reset occurs, the reset status register can be used to see which reset or resets have been asserted on the cpuModule.

The user has the ability to see which resets have been asserted. Resets can also be cleared.

•Examine Resets: Reading from I/O port 0x457 will indicate if a reset has been asserted. If a 1 is read, the corresponding reset has been assserted. If a 0 is read from the bit, the reset has not been asserted

•Clear Reset: Each reset can be cleared by writing a 1 to the selected bit of I/O port 0x457.

Table 52 Reset Status I/O Address 457h - Read Access

D7 D6 D5 D4 D3 D2 D1 D0

Main Power (+5V)
		Non-Standby Power		Standby Power
0	= reset asserted	0	= reset asserted	0	= reset asserted
1	= no reset	1	= no reset	1	= no reset

CPU Core Power		Memory Power		Reserved
0	= reset asserted	0	= reset asserted
1	= no reset	1	= no reset

PCI Reset

0 = reset asserted

1 = no reset

Utility Reset

0 = reset asserted

1 = no reset

Table 53 Reset Status I/O Address 457h - Write Access

D7 D6 D5 D4 D3 D2 D1 D0

Main Power (+5V) 1 = clear reset

Non-Standby Power 1 = clear reset

Standby Power 1 = clear reset

PCI Reset

1 = clear reset

CPU Core Power	Memory Power	Reserved	Utility Reset
1 = clear reset	1 = clear reset		1 = clear reset

BDM-610000050 Rev A Chapter 4: Using the cpuModule 71