vsc055xkm-01 Maxim Integrated Products, Inc., vsc055xkm-01 Datasheet - Page 23

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

VSC055-01
Data Sheet
3.2.4
3.2.5
03h: General-Purpose I/O Port 3 Data (GPD3)
The following table shows the bit assignments for the General-Purpose I/O Port 3 Data register. Control of
the individual I/O pins in this register can be overridden by the PBC0, PBC1, PBC2, and PBC3 registers
when port bypass control is required.
04h: General-Purpose I/O Port 4 Data (GPD4)
The following table shows the bit assignments for the General-Purpose I/O Port 4 Data register. Control of
the individual I/O pins in this register can be overridden by the PBC4, PBC5, PBC6, and PBC7 registers
when port bypass control is required.
Register Name:
Address:
Reset Value:
Bit
7:0
Register Name:
Address:
Reset Value:
Bit
7:0
Bit Label
GPD3.7-0
Bit Label
GPD4.7-0
GPD4
04h
XXXX_XXXXb
GPD3
03h
XXXX_XXXXb
Access Description
R/W
Access
R/W
General-Purpose Data
When the I/O pin is enabled as an output, writing these bits determines the data
value that will be present on the corresponding I/O pin.
If the I/O pin is enabled as an input, reading these register bits represents the
current voltage applied to the pin. At no time do the bits directly represent the
value latched into the data register.
If a pin is enabled as an input and there is no signal applied, weak internal pull-
up resistors hold the pin at a binary 1.
After a reset or power on, the register bits are set to a binary 1, but the value
returned from a register read is the level applied to the pin since each pin is an
input by default.
Description
General-Purpose Data
When the I/O pin is enabled as an output, writing these bits determines the data
value that will be present on the corresponding I/O pin.
If the I/O pin is enabled as an input, reading these register bits represents the
current voltage applied to the pin. At no time do the bits directly represent the
value latched into the data register.
If a pin is enabled as an input and there is no signal applied, weak internal pull-
up resistors hold the pin at a binary 1.
After a reset or power on, the register bits are set to a binary 1, but the value
returned from a register read is the level applied to the pin since each pin is an
input by default.
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January 2008
Revision 4.1