MC68HC908MR8 Datasheet, PDF (289/372 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
Port C
READ DDRC ($0006)
WRITE DDRC ($0006)
RESET
WRITE PTC ($0002)
READ PTC ($0002)
DDRCx
PTCx
PTCx
Figure 14-10. 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 14-3 summarizes
the operation of the port C pins.
Table 14-3. Port C Pin Functions
DDRC PTC
Bit Bit
I/O Pin Mode
Accesses to DDRC
Read/Write
Accesses to PTC
Read
Write
0
X⁽¹⁾ Input, Hi-Z⁽²⁾
DDRC[1:0]
Pin
PTC[1:0]⁽³⁾
1
X
Output
DDRC[1:0]
PTC[1:0] PTC[1:0]
1. X = don’t care
2. Hi-Z = high impedance on PTC0 and a pull-down R_PD on PTC1
3. Writing affects data register, but does not affect input.
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
289