mc68hc705c4acfn Freescale Semiconductor, Inc, mc68hc705c4acfn Datasheet - Page 80

• Manufacturer Part Number: mc68hc705c4acfn
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Parallel Input/Output (I/O)
Technical Data
80
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
MC68HC705C4A • MC68HSC705C4A — Rev. 3.0
DDRB7–DDRB0
DDRB7–DDRB0
Read/Write
PB7–PB0
Accesses to PORTB
Read
Pin
MOTOROLA
DD
PB7–PB0
PB7–PB0
Write
or V
(2)
SS
,