MC68HC908LD64 Datasheet, PDF (304/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
NOTE:
Care must be taken when reading port C while applying analog voltages
to ADC5–ADC0 pins. If the appropriate ADC channel is not enabled,
excessive current drain may occur if analog voltages are applied to the
PTCx/ADCx pin, while PTC is read as a digital input. Those ports not
selected as analog input channels are considered digital I/O ports.
19.5.2 Data Direction Register C
Data direction register C (DDRC) determines whether each port C pin is
an input or an output. Writing a logic 1 to a DDRC bit enables the output
buffer for the corresponding port C pin; a logic 0 disables the output
buffer.
Address:
Read:
Write:
Reset:
$0006
Bit 7
0
6
5
4
3
2
1
DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1
0
0
0
0
0
0
0
= Unimplemented
Figure 19-11. Data Direction Register C (DDRC)
Bit 0
DDRC0
0
DDRC[6:0] — Data Direction Register C Bits
These read/write bits control port C data direction. Reset clears
DDRC[6:0], configuring all port C pins as inputs.
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
NOTE: Avoid glitches on port C pins by writing to the port C data register before
changing data direction register C bits from 0 to 1.
Figure 19-12 shows the port C I/O logic.
Data Sheet
304
Input/Output (I/O) Ports
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor