pc87591l National Semiconductor Corporation, pc87591l Datasheet - Page 116

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

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Embedded Controller Modules
4.5.3
Input Only Port with Alternate Function
The General-Purpose Input (GPI) port (Py) contains a subset of the GPIO functions. It can be used as a GPI port or as an
input signal for an alternate function. Figure 35 illustrates its functionality.
PIN
Px
or Py
Alternative Function Register
GPI Port Py
Weak Pull-Up Register
Alt Device Data Input
Alt Device Direction
Direction Register
Alternate Function Register
To MIWU
Data In Register
Data In Read
Alt Device Data Input
Data Out
Register
Figure 34. GPIO Port Px Output with Echo Schematic Diagram
Data Input Register
Data Input Read
Weak Pull-Up
{
{
{
{
Figure 35. GPI Port Py Schematic Diagram
PxDIN
(Continued)
{
{
(PxDOUT)
(PxWPU)
PxAlt
(PxDIR)
PyDIN
Weak Pull-Up
116
(PyWPU)
PyAlt
Alt
Alt
Echo EN
Alt
Alt
Alt
Alt
Pull-Up
Pull-Up
Revision 1.07
Px
PIN
PIN