MC68HC711D3_05 Datasheet, PDF (63/138 Pages) Freescale Semiconductor, Inc – Microcontrollers

Port C
5.4 Port C
Port C is an 8-bit, general-purpose I/O port with a data register (PORTC) and a data direction register
(DDRC). In the single-chip mode, port C pins are general-purpose I/O pins (PC7–PC0). In the
expanded-multiplexed mode, port C pins are configured as multiplexed address/data pins. During the
address cycle, bits 7–0 of the address are output on PC7–PC0. During the data cycle, bits 7–0
(PC7–PC0) are bidirectional data pins controlled by the R/W signal.
5.4.1 Port C Control Register
Address: $0002
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
0
CWOM
0
0
0
0
0
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 5-4. Port C Control Register (PIOC)
CWOM — Port C Wire-OR Mode Bit
1 = Port C outputs are open drain (to facilitate testing)
0 = Port C operates normally
5.4.2 Port C Data Register
Address: $0003
Bit 7
6
5
4
3
2
1
Bit 0
Read:
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 5-5. Port C Data Register (PORTC)
PORTC can be read at any time. Inputs return the sensed levels at the pin, while outputs return the input
level of the port C pin drivers. If PORTC is written, the data is stored in an internal latch and can be driven
only if port C is configured for general-purpose outputs in single-chip or bootstrap mode.
Port C pins are general-purpose inputs out of reset in single-chip and bootstrap modes. These pins are
multiplexed low-order address and data bus lines out of reset in expanded-multiplexed and test modes.
5.4.3 Port C Data Direction Register
Address:
Read:
Write:
Reset:
$0007
Bit 7
6
5
4
3
2
1
DDC7 DDC6 DDC5 DDC4 DDC3 DDC2 DDC1
0
0
0
0
0
0
0
Figure 5-6. Data Direction Register for Port C (DDRC)
Bit 0
DDC0
0
DDC7–DDC0 — Data Direction Bits for Port C
1 = Corresponding port C pin is configured as output
0 = Corresponding port C pin is configured for input only
MC68HC711D3 Data Sheet, Rev. 2.1
Freescale Semiconductor
63