MC68HC705JJ7 Datasheet, PDF (67/164 Pages) Freescale Semiconductor, Inc – Microcontrollers

Port C (28-Pin Versions Only)
7.4 Port C (28-Pin Versions Only)
Port C is an 8-bit, general-purpose, bidirectional I/O port with these features:
• Individual programmable pulldown devices
• High current sinking capability on all port C pins, with a maximum total for port C
• High current sourcing capability on all port C pins, with a maximum total for port C
7.4.1 Port C Data Register
The port C data register (PORTC) contains a bit for each of the port C pins. When a port C pin is
programmed to be an output, the state of its data register bit determines the state of the output pin. When
a port C pin is programmed to be an input, reading the port C data register returns the logic state of the pin.
Address: $0002
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
Write:
Reset:
Unaffected by reset
Figure 7-13. Port C Data Register (PORTC)
PC7–PC0 — Port C Data Bits
These read/write bits are software programmable. Data direction of each bit is under the control of the
corresponding bit in the port C data direction register (DDRC). Reset has no effect on port C data.
7.4.2 Data Direction Register C
The contents of the port C data direction register (DDRC) determine 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 associated port C pin. A
DDRC bit set to a logic 1 also disables the pulldown device for that pin. Writing a logic 0 to a DDRC bit
disables the output buffer for the associated port C pin. A reset initializes all DDRC bits to logic 0s,
configuring all port C pins as inputs.
Address:
Read:
Write:
Reset:
$0006
Bit 7
6
5
4
3
2
1
DDRC7 DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1
0
0
0
0
0
0
0
Figure 7-14. Data Direction Register C (DDRC)
Bit 0
DDRC0
0
DDRC7–DDRC0 — Port C Data Direction Bits
These read/write bits control port C data direction. Reset clears the DDRC7–DDRC0 bits.
1 = Corresponding port C pin configured as output and pulldown device disabled
0 = Corresponding port C pin configured as input
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
Freescale Semiconductor
67