MC68HC705P9 Datasheet, PDF (79/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Parallel I/O Ports
Port C
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 8. 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 the positive ADC
reference voltage.
AN[3:0] — Analog Input Bits
When the ADC is turned on, the AN0–AN3 pins are
software-selectable analog inputs. 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.
9-mc68hc705p9
MOTOROLA
Parallel I/O Ports
79