mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 332

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports
18.6.2 Data Direction Register D (DDRD)
Data Sheet
332
NOTE:
Address:
Data direction register D determines whether each port D pin is an input
or an output. Writing a logic 1 to a DDRD bit enables the output buffer for
the corresponding port D pin; a logic 0 disables the output buffer.
DDRD[7:0] — Data Direction Register D Bits
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.
the port D I/O logic.
Reset:
Read:
Write:
These read/write bits control port D data direction. Reset clears
DDRD[7:0], configuring all port D pins as inputs.
1 = Corresponding port D pin configured as output
0 = Corresponding port D pin configured as input
DDRD7
READ DDRD ($0007)
WRITE DDRD ($0007)
WRITE PTD ($0003)
READ PTD ($0003)
$0007
Bit 7
Figure 18-14. Data Direction Register D (DDRD)
0
Input/Output (I/O) Ports
DDRD6
6
0
Figure 18-15. Port D I/O Circuit
RESET
DDRD5
5
0
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
DDRD4
DDRDx
PTDx
4
0
DDRD3
3
0
DDRD2
Freescale Semiconductor
Figure 18-15
2
0
DDRD1
1
0
shows
DDRD0
Bit 0
0
PTDx