S908QC16CDRE FREESCALE [Freescale Semiconductor, Inc], S908QC16CDRE Datasheet - Page 115

• Manufacturer Part Number: S908QC16CDRE
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

DDRD[7:0] — Data Direction Register D Bits
When DDRDx is a 1, reading address $0003 reads the PTDx data latch. When DDRDx is a 0, reading
address $0003 reads the voltage level on the pin. The data latch can always be written, regardless of the
state of its data direction bit.
11.6.3 Port D Input Pullup Enable Register
The port D input pullup enable register (PTDPUE) contains a software configurable pullup device for each
of the eight port D pins. Each bit is individually configurable and requires the corresponding data direction
register, DDRDx, be configured as input. Each pullup device is automatically and dynamically disabled
when its corresponding DDRDx bit is configured as output.
PTDPUE[7:0] — Port D Input Pullup Enable Bits
Freescale Semiconductor
These read/write bits control port D data direction. Reset clears DDRD[7:0], configuring all port D pins
as inputs.
These read/write bits are software programmable to enable pullup devices on port D pins
1 = Corresponding port D pin configured as output
0 = Corresponding port D pin configured as input
1 = Corresponding port D pin configured to have internal pull if its DDRD bit is set to 0
0 = Pullup device is disconnected on the corresponding port D pin regardless of the state of its
DDRD bit.
Avoid glitches on port D pins by writing to the port D data register before
changing data direction register D bits from 0 to 1.
port D I/O logic.
Reset:
Read:
Write:
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 2
Figure 11-16. Port D Input Pullup Enable Register (PTDPUE)
READ DDRD ($0007)
WRITE DDRD ($0007)
WRITE PTD ($0003)
READ PTD ($0003)
PTDPUE7 PTDPUE6 PTDPUE5 PTDPUE4 PTDPUE3 PTDPUE2 PTDPUE1 PTDPUE0
Bit 7
0
6
0
RESET
Figure 11-15. Port D I/O Circuit
5
0
DDRDx
NOTE
PTDx
4
0
3
0
Figure 11-15
2
0
PTDPUEx
1
0
shows the
PULLUP
PTDx
Bit 0
0
Port D
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