MC68HC708XL36 FREESCALE [Freescale Semiconductor, Inc], MC68HC708XL36 Datasheet - Page 293

• Manufacturer Part Number: MC68HC708XL36
• Description: HCMOS Microcontroller Unit
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

11-ports_a
MOTOROLA
NOTE:
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.
Figure 13
When bit DDRDx is a logic 1, reading address $0003 reads the PDx data
latch. When bit DDRDx is a logic 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.
the port D pins.
1. Writing affects data register, but does not affect input.
These read/write bits control port D data direction. Reset clears
DDRD[7:0], configuring all port D pins as inputs.
Freescale Semiconductor, Inc.
Data Direction Bit
For More Information On This Product,
1 = Corresponding port D pin configured as output
0 = Corresponding port D pin configured as input
0
1
shows the port D I/O logic.
READ DDRD ($0007)
WRITE DDRD ($0007)
WRITE PORTD ($0003)
READ PORTD ($0003)
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I/O Ports
Table 5. Port D Pin Operation
Figure 13. Port D I/O Circuit
RESET
Input, high-impedance
I/O Pin Mode
Output
Table 5
DDRDx
PDx
summarizes the operation of
Read
Latch
Access to Data Bit
Pin
MC68HC708XL36
Latch
Write
Latch
I/O Ports
Port D
(1)
293
PDx