MIC2593_08 Datasheet, PDF (19/26 Pages) Micrel Semiconductor – Dual-Slot PCI Hot Plug Controller

Micrel, Inc.
Status Register, Slot B (STATB)
8-Bits, Read-Only
D[7]
read-only
FAULTB
D[6]
read-only
MAINB
D[5]
read-only
VAUXB
Status Register, Slot B (STATB)
D[4]
D[3]
read/write
read/write
VAUXBF
12MVBF
D[2]
read/write
12VBF
D[1]
read/write
5VBF
MIC2593
D[0]
read/write
3VBF
Bit(s)
FAULTB
Function
FAULT Status, Slot B
MAINB
MAIN Enable Status, Slot B
VAUXB
VAUX Enable Status, Slot B
VAUXBF
12MVBF
12VBF
5VBF
3VBF
Overcurrent Fault: VAUXB supply B
Overcurrent Fault: –12V supply B
Overcurrent Fault: +12V supply B
Overcurrent Fault: 5V supply B
Overcurrent Fault: 3V supply B
Operation
1 = /FAULTB pin asserted
(/FAULTB pin is LOW)
0 = /FAULTB pin de-asserted
(/FAULTB pin is HIGH)
See Notes 1 and 2
Represents the actual state (on/off) of the four Main
Power outputs for Slot B (+12V, –12V, +5V and +3.3V)
1 = Main Power ON
0 = Main Power OFF
Represents the actual state (on/off) of the Auxiliary
Power output for Slot B
1 = AUX Power ON
0 = Main Power OFF
1 = Fault, 0 = No fault
1 = Fault, 0 = No fault
1 = Fault, 0 = No fault
1 = Fault, 0 = No fault
1 = Fault, 0 = No fault
Power-Up Default Value:
0000 0000_b = 00_h
Command_Byte Value (R/W): 0000 0101_b = 05_h
The power-up default value is 00_h. Both slots are 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 or by clearing active status bits.
Note 1.
Note 2.
If FAULTB has been set by an overcurrent condition on one or more of the MAIN outputs, the ONB input must go LOW to reset FAULTB.
If FAULTB has been set by a VAUXB overcurrent event, the AUXENB input must go LOW to reset FAULTB.
If an overcurrent has occurred on both a MAIN output and the VAUX output of slot B, both ONB and AUXENB of the slot must go low to
reset FAULTB.
Neither the FAULTB bit nor the /FAULTB pin is active when the MIC2593 power paths are controlled by the System Management
Interface. When using SMI power path control, AUXENB and ONB pins for that slot must be tied to GND.
September 2008
19
M9999-092208