MC908AB32CFUE Datasheet, PDF (322/392 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
DDRCx
PTCx
PTCx
READ PTC ($0002)
MCLK
PTC2 ONLY
Figure 17-10. Port C I/O Circuit
MCLKEN
When DDRCx is a logic 1, reading address $0002 reads the PTCx data
latch. When 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 17-4 summarizes the operation of the port C pins.
Table 17-4. Port C Pin Functions
DDRC
Bit
PTC Bit
I/O Pin Mode
Accesses to DDRC
Read/Write
0
2
Input, Hi-Z
DDRC7
1
2
Output
DDRC7
0
X⁽¹⁾
Input, Hi-Z⁽²⁾
DDRC[5:0]
1
X
Output
DDRC[5:0]
Notes:
1. X = don’t care; except PTC2.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Accesses to PTC
Read
Write
Pin
PTC2
0
—
Pin
PTC[5:0]⁽³⁾
PTC[5:0] PTC[5:0]
Technical Data
322
Input/Output (I/O) Ports
MC68HC908AB32 — Rev. 1.1
Freescale Semiconductor