MC68HC908QY2 MOTOROLA [Motorola, Inc], MC68HC908QY2 Datasheet - Page 168

• Manufacturer Part Number: MC68HC908QY2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Input/Output (I/O) Ports
12.4.2 Data Direction Register B
168
MC68HC908QY4•MC68HC908QT4•MC68HC908QY2•MC68HC908QT2•MC68HC908QY1•MC68HC908QT1
NOTE:
Address: $0005
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.
DDRB[7:0] — Data Direction Register B Bits
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.
the port B I/O logic.
Reset:
Read:
Write:
These read/write bits control port B data direction. Reset clears
DDRB[7:0], configuring all port B pins as inputs.
1 = Corresponding port B pin configured as output
0 = Corresponding port B pin configured as input
READ DDRB ($0005)
WRITE DDRB ($0005)
WRITE PTB ($0001)
READ PTB ($0001)
DDRB7
Bit 7
0
Figure 12-7. Data Direction Register B (DDRB)
Input/Output (I/O) Ports
DDRB6
6
0
RESET
Figure 12-8. Port B I/O Circuit
DDRB5
5
0
DDRB4
DDRBx
PTBx
4
0
DDRB3
3
0
DDRB2
2
0
Figure 12-8
PTBPUEx
DDRB1
1
0
MOTOROLA
shows
30 k
DDRB0
Bit 0
PTBx
0