MC68HC908JK3 MOTOROLA [Motorola, Inc], MC68HC908JK3 Datasheet - Page 151

• Manufacturer Part Number: MC68HC908JK3
• Description: MC68HC908JK1
• Manufacturer: MOTOROLA [Motorola, Inc]

12.4.2 Port A Input Pull-up Enable Register (PTAPUE)
MC68H(R)C908JL3
MOTOROLA
—
Rev. 1.0
When DDRAx is a logic 1, reading address $0000 reads the PTAx data
latch. When DDRAx is a logic 0, reading address $0000 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 A Input Pull-up Enable Register (PTAPUE) contains a software
configurable pull-up device for each if the seven port A pins. Each bit is
individually configurable and requires the corresponding data direction
register, DDRAx be configured as input. Each pull-up device is
automatically and dynamically disabled when its corresponding DDRAx
bit is configured as output.
READ DDRA ($0004)
WRITE DDRA ($0004)
WRITE PTA ($0000)
READ PTA ($0000)
Figure 12-4. Port A I/O Circuit
I/O Ports
RESET
DDRAx
PTAx
Port A Data Register (PTA)
To Keyboard Interrupt Circuit
PTAPUEx
Technical Data
I/O Ports
30k
PTAx
151