pc87591l National Semiconductor Corporation, pc87591l Datasheet - Page 114

• Manufacturer Part Number: pc87591l
• Description: Lpc Mobile Embedded Controllers
• Manufacturer: National Semiconductor Corporation

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Embedded Controller Modules
4.5.1
4.5.2
Bidirectional Port with Alternate Function
The GPIO port enables access to input and output pins. It also controls the pin usage either as an I/O port or in its alternate
function. Figure 33 illustrates this functionality.
General-Purpose Input/Output (GPIO) Port (Px).
— Each pin functions as input or output signal.
— Direction register controls the port direction.
— Weak pull-up.
— Read-back on all registers.
General-Purpose Input (GPI) Port (Py).
— All port pins function as input signals.
— Weak pull-up.
— Read-back on all control registers.
General-Purpose Output (GPO) Port (Pz).
— All pins function as output signals.
— Read-back on all registers.
General-Purpose Input/Output (GPIO) Port (Pw).
— DEV environment support.
— Each pin functions as input or output signal.
— Direction register controls the port direction.
— Read-back on all registers.
Each I/O pin can be configured as a GPIO port or as an alternate function.
— Some I/O or input pins can provide interrupt functions.
— Pins shared with DEV environment signals.
— Off-chip implementation supported in DEV environments.
— Binary and cycle-by-cycle compatibility between environments.
Features
GPIO Port Px
Weak Pull-Up
Register
Alt Device Direction
Direction
Register
Alt Device Data
Output
Data Output
Register
Data Input Register
Alt Device Data Input
Data Input Read
Alternate
Function
Register
{
{
{
{
Figure 33. GPIO Port Px Schematic Diagram
PxDIN
(Continued)
Weak Pull-Up
(PxDOUT)
(PxWPU)
Data Out
Direction
(PxDIR)
PxAlt
114
Alt
Alt
Alt
Alt
Pull-Up
Revision 1.07
PIN