MC68HC11PH8 Datasheet, PDF (80/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

4.1
Port A
Port A is an 8-bit bidirectional port, with both data and data direction registers. In addition to their
I/O capability, port A pins are shared with timer functions, as shown in the following table.
Pin
Alternate function
PA0 IC3

4
PA1 IC2


PA2 IC1


PA3 OC5 and/or OC1, or IC4


See Section 8 for
PA4 OC4 and/or OC1


more information.
PA5 OC3 and/or OC1


PA6 OC2 and/or OC1


PA7 PAI and/or OC1

On reset the pins are configured as general purpose high-impedance inputs.
4.1.1 PORTA — Port A data register
Port A data (PORTA)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0000 PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0 undeÞned
This is a read/write register and is not affected by reset. The bits may be read and written at any
time, but, when a pin is allocated to its alternate function, a write to the corresponding register bit
has no effect on the pin state.
4.1.2 DDRA — Data direction register for port A
Data direction A (DDRA)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0001 DDA7 DDA6 DDA5 DDA4 DDA3 DDA2 DDA1 DDA0 0000 0000
DDA[7:0] — Data direction for port A
1 (set) – The corresponding pin is configured as an output.
0 (clear) – The corresponding pin is configured as an input.
MOTOROLA
4-2
PARALLEL INPUT/OUTPUT
TPG
MC68HC11PH8