s908az32ag2cfue Freescale Semiconductor, Inc, s908az32ag2cfue Datasheet - Page 248

• Manufacturer Part Number: s908az32ag2cfue
• Description: M68hc08 Microcontrollers 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

I/O Ports
23.4 Port C
Port C is an 6-bit general-purpose bidirectional I/O port. Note that PTC5 is only available on 64-pin
package options.
23.4.1 Port C Data Register
The port C data register contains a data latch for each of the six port C pins.
PTC[5:0] — Port C Data Bits
MCLK — System Clock Bit
23.4.2 Data Direction Register C
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.
MCLKEN — MCLK Enable Bit
DDRC[5:0] — Data Direction Register C Bits
248
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 (5:0).
The system clock is driven out of PTC2 when enabled by MCLKEN bit in PTCDDR7.
This read/write bit enables MCLK to be an output signal on PTC2. If MCLK is enabled, DDRC2 has no
effect. Reset clears this bit.
These read/write bits control port C data direction. Reset clears DDRC[7:0], configuring all port C pins
as inputs.
1 = MCLK output enabled
0 = MCLK output disabled
1 = Corresponding port C pin configured as output
0 = Corresponding port C pin configured as input
Functions:
Address:
Alternate
Address:
Reset:
Reset:
Read:
Read:
Write:
Write:
MCLKEN
$0002
$0006
Bit 7
Bit 7
R
R
R
0
0
Figure 23-9. Data Direction Register C (DDRC)
= Reserved
= Reserved
Figure 23-8. Port C Data Register (PTC)
R
R
6
0
6
0
0
MC68HC908AZ32A Data Sheet, Rev. 2
DDRC5
PTC5
5
5
0
DDRC4
Unaffected by Reset
PTC4
4
4
0
DDRC3
PTC3
3
3
0
DDRC2
MCLK
PTC2
2
2
0
DDRC1
PTC1
1
1
0
Freescale Semiconductor
DDRC0
PTC0
Bit 0
Bit 0
0