MC68HC908LB8_05 Datasheet, PDF (140/234 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Input/Output (I/O) Ports
Table 14-3. Port C Pin Functions
PTCPUE
Bit
DDRC
Bit
PTC
Bit
I/O Pin
Mode
1
0
X⁽²⁾
Input, V_DD(3)
0
0
X
Input, Hi-Z⁽⁵⁾
X
1
X
Output
NOTES:
1. Output does not apply to PTC2.
2. X = Don’t care
3. I/O pin pulled up to V_DD by internal pullup device.
4. Writing affects data register, but does not affect input.
5. Hi-Z = High impedance
Accesses
to DDRC
Read/Write
DDRC1–DDRC0
DDRC1–DDRC0
DDRC1–DDRC0
Accesses
to PTC
Read
Write⁽¹⁾
Pin
PTC1–PTC0⁽⁴⁾
Pin
PTC1–PTC0⁽⁴⁾
PTC2–PTC0
PTC1–PTC0
14.4.3 Port C Input Pullup Enable Register
The port C input pullup enable register (PTCPUE) contains a software configurable pullup device for each
of the seven port C pins. Each bit is individually configurable and requires that the data direction register,
DDRC, bit be configured as an input. Each pullup is automatically and dynamically disabled when a port
bit’s DDRC is configured for output mode.
Address: $000E
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
0
0
0
OSC2EN
PTCPUE2 PTCPUE1 PTCPUE0
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 14-12. Port C Input Pullup Enable Register (PTCPUE)
OSC2EN — Enable PTC1 on OSC2 Pin
This read/write bit configures the OSC2 pin function when internal oscillator or RC oscillator option is
selected. this bit has no effect for the XTAL or external oscillator options.
1 = OSC2 pin outputs the internal or RC oscillator clock (BUSCLKX4)
0 = OSC2 pin configured for PTC1 I/O, having all the interrupt and pullup functions
PTCPUE2–PTCPUE0 — Port C Input Pullup Enable Bits
These writable bits are software programmable to enable pullup devices on an input port bit.
1 = Corresponding port C pin configured to have internal pullup
0 = Corresponding port C pin internal pullup disconnected
MC68HC908LB8 Data Sheet, Rev. 1
140
Freescale Semiconductor