vsc055xkm-01 Maxim Integrated Products, Inc., vsc055xkm-01 Datasheet - Page 22

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

3.2.2
3.2.3
Revision 4.1
January 2008
01h: General-Purpose I/O Port 1 Data (GPD1)
The following table shows the bit assignments for the General-Purpose I/O Port 1 Data register.
02h: General-Purpose I/O Port 2 Data (GPD2)
The following table shows the bit assignments for the General-Purpose I/O Port 2 Data register.
Register Name:
Address:
Reset Value:
Bit
7:0
Register Name:
Address:
Reset Value:
Bit
7:0
Bit Label
GPD1.7-0
Bit Label
GPD2.7-0
GPD1
01h
XXXX_XXXXb
GPD2
02h
XXXX_XXXXb
Access Description
R/W
Access Description
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, however, the
value returned from a register read is the level applied to the pin since each pin is
an input by default.
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, however, 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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VSC055-01
Data Sheet