MC68HC05P9A Datasheet, PDF (73/158 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Port C
Freescale Semiconductor, Inc.
Parallel I/O Ports
Port C
Port C is an 8-bit I/O port that shares five of its pins with the A/D
converter (ADC). The five shared pins are available for general-purpose
I/O functions when the ADC is disabled.
Port C Data
Register (PORTC)
The port C data register contains a latch for each of the eight port C pins.
$0002 Bit 7
6
5
4
3
2
1
Bit 0
Read:
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
Write:
Reset:
Unaffected by reset
Alternate
Function:
V_RH
AN0
AN1
AN2
AN3
Figure 35. Port C Data Register (PORTC)
PC[7:0] — Port C Data Bits
These read/write bits are software programmable. Data direction of
each port C pin is under the control of the corresponding bit in data
direction register C. Reset has no effect on port C data.
V_RH — Voltage Reference High Bit
When the ADC is turned on, the PC7/V_RH pin is configured as an input
and is the positive ADC reference voltage.
AN[3:0] — Analog Input Bits
When the ADC is turned on, the AN0–AN3 pin that is selected as the
analog input is configured as an input. Unused analog inputs can be
used as digital inputs, but pins PC3/AN3, PC4/AN2, PC5/AN1, and
PC6/AN0 cannot be used as digital outputs while the ADC is on. Only
pins PC0, PC1, and PC2 can be used as digital outputs when the
ADC is on.
13-mc68hc05p9a
MOTOROLA
Parallel I/O Ports
73
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