vsc055xkm-01 Maxim Integrated Products, Inc., vsc055xkm-01 Datasheet - Page 110

• Manufacturer Part Number: vsc055xkm-01
• Description: Enhanced I?c Backplane Controller
• Manufacturer: Maxim Integrated Products, Inc.

3.2.97 F8h: Backplane Controller Interrupt Status (BCIS)
Revision 4.1
January 2008
The following table shows the bit assignments for the Backplane Controller Interrupt Status register.
Bit
0
Register Name:
Address:
Reset Value:
Bit
7:0
Bit Label
GPD
Bit Label
IA7-0
BCIS
F8h
0000_0000b
Access
R/W
Access
R
Description
General-Purpose Data
When the I/O pin has been enabled as an output, writing this bit determines the
data value that is present on the corresponding I/O pin.
If the I/O pin is enabled as an input, reading this register bit represents the
current voltage applied to the pin.
At no time does this bit directly represent the value latched into the data
register. If the pin is enabled as an input and there is no signal applied, a weak
internal pull-up resistor holds the pin at a binary 1. After a reset or power on,
this register bit is set to a binary 1; however, the value returned from a register
read is the level applied to the pin since each pin is an input by default.
Description
Interrupt Active
These eight bits determine the currently active interrupt source, which is
enabled through the following registers: Port Bypass Control, Fan Speed
Control, Bit Control, or General-Purpose Timer. The addresses of these
registers are generated as an indicator of the currently active interrupt source.
If multiple interrupt sources are active, the value generated is prioritized from
the lowest binary value to the highest binary value.
To clear the current interrupt and de-assert the INT# pin, a value of FFh must
be written to this register. If a higher binary value or lower priority interrupt
source is still active, the new value is generated and the INT# pin re-asserts.
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VSC055-01
Data Sheet