mc68hc05l25 Freescale Semiconductor, Inc, mc68hc05l25 Datasheet - Page 68

• Manufacturer Part Number: mc68hc05l25
• Description: M68hc05 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output Ports (I/O)
7.4.1 Port C Data Register
Each port C input pin has a corresponding bit in the port C data register. Regardless of the peripheral
configuration, any read of the port C data register will return the logic state of the corresponding I/O pin.
The port C data register is unaffected by reset.
7.4.2 Port C Data Direction Register
Each port C I/O pin can be programmed as an input by clearing the corresponding bit in the DDRC or
programmed as an output by setting the corresponding bit in the DDRC. The DDRC can be accessed at
address $0002 of the option map. The DDRC is cleared by reset.
7.4.3 Port C Pullup Register
Each port C pin can have a software programmable pullup device enabled by the RCR2 select bit RC.
The pullup is activated whenever the RC bit in the RCR2 is set. Since reset clears the RCR2, all pins will
initialize with the pullup devices disabled. See
7.4.4 Port C Wired-OR Mode Register
Port C bits 0 and 1 are configured for output pins and can have software programmable wired-OR mode
(open drain) output enabled by the CWOM bit in the WOMR. Since reset clears the WOMR, the wired-OR
mode is disabled on reset. Port C bits 2 and 3, when configured as an output port, have wired-OR mode
output only. See
7.4.5 I/O Pin Truth Tables
Table 7-9
68
through
Address:
Address:
Reset:
Reset:
Read:
Read:
Write:
Write:
7.5.8 Open Drain Output Control
Table 7-12
$0002
Bit 7
Bit 7
Option — $0002
Figure 7-18. Port C Data Direction Register (DDRC)
0
0
0
0
Figure 7-17. Port C Data Register (PORTC)
summarize the input, pullup, wired-OR mode, and SPI pin programming.
= Unimplemented
= Unimplemented
6
0
0
6
0
0
MC68HC05L25 Data Sheet, Rev. 3.1
5
0
0
5
0
0
7.5.7 Resistor Control Register
Register.
4
0
0
4
0
0
U = Unaffected
DDRC3
PC3
U
3
3
0
DDRC2
PC2
U
2
2
0
DDRC1
PC1
2.
U
1
1
0
Freescale Semiconductor
DDRC0
Bit 0
PC0
Bit 0
U
0