MIC2590B Datasheet, PDF (16/24 Pages) Micrel Semiconductor – Dual-Slot PCI Hot Plug Controller

MIC2590B
Micrel
Status Register, Slot A (STATA), 8-Bits Read Only
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
read-only read-only read-only read-write read-write read-write read-write read-write
FAULTA MAINA VAUXA VAUXAF 12MVAF 12VAF 5VAF 3VAF
Status Register, Slot B (STATB), 8-Bits Read Only
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
read-only read-only read-only read-write read-write read-write read-write read-write
FAULTA MAINA VAUXA VAUXAF 12MVAF 12VAF 5VAF 3VAF
Bit(s)
FAULTA
MAINA
VAUXA
VAUXFA
Function
Operation
FAULT Pin Status, Notes 1 & 2
Slot A
MAIN Enable Status,
Slot A
Represents actual state
(on/off) of the four main
power outputs for Slot A.
(+12V, +5V, +3.3V and –12V)
1 = MAIN Power On
0 = MAIN Power Off
VAUX Enable Status
Slot A
Represents actual state
(on/off) of the auxiliary
power outputs for Slot A.
1 = AUX Power On
0 = AUX Power Off
Overcurrent Fault
VAUX Supply
1 = Fault; 0 = No Fault
12MVFA Overcurrent Fault
–12V Supply
1 = Fault; 0 = No Fault
12VFA
Overcurrent Fault
+12V Supply
1 = Fault; 0 = No Fault
5VFA
3VFA
Overcurrent Fault
5V Supply
Overcurrent Fault
3.3V Supply
1 = Fault; 0 = No Fault
1 = Fault; 0 = No Fault
Power-Up Default Value:
0000 0000_b = 00_h
Read Command Byte (R/W): 0000 0100_b = 04_h
The power-up default value is 00_h. The slot is disabled
upon power-up, i.e., all supply outputs are off. In response
to an overcurrent fault condition, writing a logical 1 back
into the active (or set) bit position will clear the bit and de-
assert /INT. The status of the /FAULTA pin is not affected
by reading the Status Register.
Bit(s)
FAULTB
MAINB
VAUXB
VAUXFB
Function
FAULT Pin Status,
Slot B
MAIN Enable Status,
Slot B
VAUX Enable Status
Slot B
Overcurrent Fault
VAUX Supply
Operation
Notes 1 & 2
Represents actual state
(on/off) of the four main
power outputs for Slot B.
(+12V, +5V, +3.3V and –12V)
1 = MAIN Power On
0 = MAIN Power Off
Represents actual state
(on/off) of the auxiliary
power outputs for Slot B.
1 = AUX Power On
0 = AUX Power Off
1 = Fault; 0 = No Fault
12MVFB Overcurrent Fault
–12V Supply
1 = Fault; 0 = No Fault
12VFB
Overcurrent Fault
+12V Supply
1 = Fault; 0 = No Fault
5VFB
3VFB
Overcurrent Fault
5V Supply
Overcurrent Fault
3.3V Supply
1 = Fault; 0 = No Fault
1 = Fault; 0 = No Fault
Power-Up Default Value:
0000 0000_b = 00_h
Read Command Byte (R/W): 0000 0101_b = 05_h
The power-up default value is 00_h. The slot is disabled
upon power-up, i.e., all supply outputs are off. In response
to an overcurrent fault condition, writing a logical 1 back
into the active (or set) bit position will clear the bit and de-
assert /INT. The status of the /FAULTB pin is not affected
by reading the Status Register.
Note 1.
Note 2.
1 = /FAULT[A/B] pin asserted, indicating a fault condition (/FAULT is LOW).
0 = /FAULT[A/B] pin is de-asserted (/FAULT is HIGH).
If FAULT[A/B] has been set by an overcurrent condition on one (or more) of the main outputs, the corresponding ON[A/B] must go LOW to
reset FAULT. If FAULT[A/B] has been set by an overcurrent on a VAUX output, the corresponding AUXEN[A/B] must go LOW to reset FAULT.
If an overcurrent has occurred on both a main output and VAUX output of a slot, both ON[A/B] and AUXEN[A/B] of the corresponding slot
must go LOW to reset FAULT.
The FAULT bits, and the /FAULT pins, are not active when the MIC2590B power paths are controlled by the System Management Interface
(SMBus). When using SMI power path control for a slot, the AUXEN and ON pins for that slot must be tied to ground.
MIC2590B
16
August 2002