MC68HC908MR8 Datasheet, PDF (285/372 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
Port B
14.4.2 Data Direction Register B
Data direction register B (DDRB) determines whether each port B pin is
an input or an output. Writing a logic 1 to a DDRB bit enables the output
buffer for the corresponding port B pin; a logic 0 disables the output
buffer.
Ad-
dress:
$0005
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Write:
DDRB6 DDRB5 DDRB4 DDRB3 DDRB2 DDRB1 DDRB0
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
Figure 14-6. Data Direction Register B (DDRB)
DDRB[6:0] — Data Direction Register B Bits
These read/write bits control port B data direction. Reset clears
DDRB[6:0], configuring all port B pins as inputs.
1 = Corresponding port B pin configured as output
0 = Corresponding port B pin configured as input
NOTE: Avoid glitches on port B pins by writing to the port B data register before
changing data direction register B bits from 0 to 1.
Figure 14-7 shows the port B I/O logic.
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
Input/Output (I/O) Ports
Technical Data
285