MC68HC705C Motorola, MC68HC705C Datasheet - Page 82

• Manufacturer Part Number: MC68HC705C
• Description: HCMOS Microcontroller Unit
• Manufacturer: Motorola

Parallel Input/Output (I/O)
Technical Data
82
NOTE:
When a port B pin is programmed as an output, reading the port bit reads
the value of the data latch and not the voltage on the pin itself. When a
port B pin is programmed as an input, reading the port bit reads the
voltage level on the pin. The data latch can always be written, regardless
of the state of its DDRB bit.
To avoid excessive current draw, tie all unused input pins to V
or for I/O pins change to outputs by writing to DDRB in user code as early
as possible.
1. Hi-Z = high impedance
2. Writing affects data register but does not affect input.
DDRB Bit
0
1
Parallel Input/Output (I/O)
I/O Pin Mode
Input, Hi-Z
Output
Table 7-2. Port B Pin Functions
(1)
Accesses to DDRB
DDRB7–DDRB0
DDRB7–DDRB0
Read/Write
MC68HC705C8A — Rev. 2.0
PB7–PB0
Accesses to PORTB
Read
Pin
MOTOROLA
DD
PB7–PB0
PB7–PB0
Write
or V
(2)
SS
,