MC68HC705P9 Datasheet, PDF (88/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Parallel Input/Output (I/O) Ports
7.5.1 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 7-8. 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.
The port C data register reads normally while the ADC is on, except
that the bit corresponding to the currently selected ADC input pin
reads as logic zero.
Writing to bits PC7–PC3 while the ADC is on can produce
unpredictable ADC results.
Technical Data
88
Parallel Input/Output (I/O) Ports
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MC68HC705P9 — Rev. 4.0
MOTOROLA