Datasheet

Input/Output (I/O) Ports
Technical Data MC68HC908LJ12 — Rev. 2.1
352 Input/Output (I/O) Ports Freescale Semiconductor
17.5.2 Data Direction Register C (DDRC)
Data direction register C 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.
DDRC[7:0] — Data Direction Register C Bits
These read/write bits control port C data direction. Reset clears
DDRC[7:0], 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 17-11 shows
the port C I/O logic.
Figure 17-11. Port C I/O Circuit
Address: $0006
Bit 7654321Bit 0
Read:
DDRC7 DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1 DDRC0
Write:
Reset:00000000
Figure 17-10. Data Direction Register B (DDRB)
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
READ PTC ($0002)
PTCx
DDRCx
PTCx
INTERNAL DATA BUS