
Input/Output (I/O) Ports
MC68HC908GP32 MC68HC08GP32 Data Sheet, Rev. 7
150
Freescale Semiconductor
16.4.3 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.
PTCPUE6–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
16.5 Port D
Port D is an 8-bit special-function port that shares four of its pins with the serial peripheral interface (SPI)
module and four of its pins with two timer interface (TIM1 and TIM2) modules. Port D also has software
configurable pullup devices if configured as an input port.
16.5.1 Port D Data Register
The port D data register (PTD) contains a data latch for each of the eight port D pins.
NOTE
Bit 7 and bit 6 of PTD are not available in a 40-pin dual in-line package.
PTD7–PTD0 — Port D Data Bits
These read/write bits are software-programmable. Data direction of each port D pin is under the control
of the corresponding bit in data direction register D. Reset has no effect on port D data.
T2CH1 and T2CH0 — Timer 2 Channel I/O Bits
The PTD7/T2CH1–PTD6/T2CH0 pins are the TIM2 input capture/output compare pins. The edge/level
select bits, ELSxB:ELSxA, determine whether the PTD7/T2CH1–PTD6/T2CH0 pins are timer channel
Address:
$000E
Bit 7
6
5
432
1
Bit 0
Read:
0
PTCPUE6
PTCPUE5
PTCPUE4
PTCPUE3
PTCPUE2
PTCPUE1
PTCPUE0
Write:
Reset:
0
000
00
= Unimplemented
Figure 16-12. Port C Input Pullup Enable Register (PTCPUE)
Address:
$0003
Bit 7
6
5
4321
Bit 0
Read:
PTD7
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0
Write:
Reset:
Unaffected by reset
Alternate Function:
T2CH1
T2CH0
T1CH1
T1CH0
SPSCK
MOSI
MISO
SS
Figure 16-13. Port D Data Register (PTD)