MC68HC908LD64 Datasheet, PDF (305/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
Port C
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
DDRCx
PTCx
PTCx
READ PTC ($0002)
Figure 19-12. Port C I/O Circuit
When bit DDRCx is a logic 1, reading address $0002 reads the PTCx
data latch. When bit DDRCx is a logic 0, reading address $0002 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 19-4 summarizes
the operation of the port C pins.
Table 19-4. Port C Pin Functions
DDRC
Bit
0
PTC Bit
X⁽¹⁾
I/O Pin Mode
Input, Hi-Z⁽²⁾
Accesses to DDRC
Read/Write
DDRC[6:0]
1
X
Output
DDRC[6:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Accesses to PTC
Read
Pin
Write
PTC[6:0]⁽³⁾
PTC[6:0] PTC[6:0]
19.5.3 Port C Options
The ADCH[4:0] bits in the ADC Status and Control Register defines
which PTCx/ADCx pin is used as an ADC input and overrides any control
from the port I/O logic by forcing that pin as the input to the analog
circuitry. (See Section 13. Analog-to-Digital Converter (ADC).)
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
Input/Output (I/O) Ports
Data Sheet
305