MC68HC908JW32_09 Datasheet, PDF (174/232 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Input/Output (I/O) Ports
13.4 Port C
Port C is a 4-bit general-purpose bidirectional I/O port. PTC[3:0] are shared with Timer.
13.4.1 Port C Data Register
The port C data register contains a data latch for each of the seven port C pins.
Address: $0002
Bit 7
6
Read:
Write:
Reset:
Additional
Function:
5
4
3
2
1
PTC3
PTC2
PTC1
Unaffected by reset
T1CH1
T1CLK
= Unimplemented
Figure 13-8. Port C Data Register (PTC)
Table 13-4 shows the port function priority table.
Bit 0
PTC0
T1CH0
Table 13-4. Port C Priority Table
MSxB:MSxA
01/10/11
00
Feature
Timer function pins
Port logic control
PTC[3:0] — Port C Data Bits
These read/write bits are software-programmable. Data direction of each port C pin is under the control
of the corresponding bit in data direction register C. Reset has no effect on port C data.
T1CH0, T1CH1 — Timer Channels I/O Bits
The PTC0/T1CH0, PTC2/T1CH1 pins are the TIM input capture/output compare pins. The edge/level
select bits, ELSxB and ELSxA, determine whether they are timer channel I/O pins or general-purpose
I/O pins. (see Chapter 8 Timer Interface Module (TIM))
TCLK1 — Timer Clock Input
The PTC1/TCLK1 pin are the external clock input for the TIM. The prescaler select bits, PS[2:0], select
PTC1/TCLK1 as the TIM clock input. When not selected as the TIM clock, they are available for
general purpose I/O. (see Chapter 8 Timer Interface Module (TIM))
NOTE
Data direction register C (DDRC) does not affect the data direction of port
C pins that are being used by the TIM. However, the DDRC bits always
determine whether reading port C returns the states of the latches or the
states of the pins.
MC68HC908JW32 Data Sheet, Rev. 6
174
Freescale Semiconductor