LPC47N237-MD SMSC [SMSC Corporation], LPC47N237-MD Datasheet - Page 76

• Manufacturer Part Number: LPC47N237-MD
• Description: 3.3V I/O CONTROLLER FOR PORT REPLICATORS AND DOCKING STATIONS
• Manufacturer: SMSC [SMSC Corporation]

13.3
Note :
Revision 0.3 (10-26-04)
GPx_nIOW
GPx_nIOR
GPIO Operation
The operation of the GPIO ports is illustrated in Figure 13.1.
Figure 13.1 is for illustration purposes only and in not intended to suggest specific implementation details.
When a GPIO port is programmed as an input, reading it through the GPIO data register latches either the
inverted or non-inverted logic value present at the GPIO pin. Writing to a GPIO port that is programmed as
an input has no effect (Table 13.3).
When a GPIO port is programmed as an output, the logic value or the inverted logic value that has been
written into the GPIO data register is output to the GPIO pin.
programmed as an output returns the last value written to the data register (Table 13.3).
SD-bit
SELECTED
FUNCTION
GPIO
Data Register
Transparent
D-TYPE
Q
D
Bit-n
GPIO
Q
D
DIRECTION
Table 13.2 - GPIO Configuration Summary
Figure 13.1 - GPIO Function Illustration
BIT
B0
0
0
1
1
0
1
DATASHEET
POLARITY
BIT
B1
Page 76
0
1
0
1
Pin is a non-inverted output.
Pin is an inverted output.
Pin is a non-inverted input.
Pin is an inverted input.
GPIO
Configuration
Register bit-1
(Polarity)
3.3v I/O Controller for Port Replicators and Docking Stations
DESCRIPTION
Reading from a GPIO port that is
GPIO
Configuration
Register bit-0
(Input/Output)
SMSC DS – LPC47N237
GPIO
PIN