pc87591l-n05 National Semiconductor Corporation, pc87591l-n05 Datasheet - Page 113

• Manufacturer Part Number: pc87591l-n05
• Description: Lpc Mobile Embedded Controller
• Manufacturer: National Semiconductor Corporation

Revision 1.2
4.0 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 34 shows its functionality.
Input Buffer
The input buffer characteristics are defined in Section 2.2 on page 38. The input buffer has an enable input. When enabled,
the buffer inputs the pin’s logic level to the on-chip modules. When disabled, the input is blocked to prevent supply leakage
currents.
PIN
Px
or Py
Alternative Function Register
GPI Port Py
Alternate Function Register
Weak Pull-Up Register
Alt Device Data Input
Alt Device Direction
Direction Register
To MIWU
Alt Device Data Input
Data In Register
Data Input Register
Data In Read
Data Input Read
Weak Pull-Up
Data Out
Register
Figure 33. GPIO Port Px Output with Echo Schematic Diagram
Figure 34. GPI Port Py Schematic Diagram
{
{
{
{
{
{
PxDIN
PyDIN
(Continued)
(PxDOUT)
Weak Pull-Up
(PxWPU)
PxAlt
(PxDIR)
(PyWPU)
PyAlt
113
Alt
Alt
Alt
Echo EN
Alt
Alt
Alt
Pull-Up
Pull-Up
PIN
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Px
PIN