MC68HC708MP16 Datasheet, PDF (325/398 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
15.5.2 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 15-9. 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 15-10 shows the port C I/O logic.
READ DDRC ($0008)
WRITE DDRC ($0008)
RESET
WRITE PTC ($0002)
DDRCx
PTCx
PTCx
READ PTC ($0002)
Figure 15-10. Port C I/O Circuit
MC68HC708MP16 — Rev. 3.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
325