mc68hc908jw32 Freescale Semiconductor, Inc, mc68hc908jw32 Datasheet - Page 170

• Manufacturer Part Number: mc68hc908jw32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Input/Output (I/O) Ports
13.3 Port B
Port B is a 3-bit general-purpose bidirectional I/O port; open-drain when configured as output.
13.3.1 Port B Data Register
The port B data register contains a data latch for each of the three port B pins.
PTB[7:0] — Port B Data Bits
LED Drive — Direct LED Driver
Pullup — Programmable Pullup
13.3.2 Data Direction Register B
Data direction register B 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.
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These read/write bits are software programmable. Data direction of each port B pin is under control of
the corresponding bit in data direction register B. Reset has no effect on port B data.
The LED direct drive bit, LEDB[7:0], in the port option control register (POCR) controls the drive
options for PTB[7:0]. (See
The Pullup control bit, PULL[7:0]EN, in the pullup control register (PULLCR) controls the optional
pullup for PTB[7:0]. (See
Additional
Additional
Function:
Function:
Address:
Address:
Reset:
Reset:
Read:
Read:
Write:
Write:
$0001
$0005
Bit 7
Bit 7
Figure 13-6. Data Direction Register D (DDRD)
13.7 Port
13.7 Port
= Unimplemented
= Unimplemented
Figure 13-5. Port B Data Register (PTB)
6
6
MC68HC908JW32 Data Sheet, Rev. 5
Options.)
Options.)
LED drive
Optional
DDRB5
pullup
PTB5
5
5
0
Unaffected by reset
4
4
3
3
2
2
LED drive
Optional
DDRB1
pullup
PTB1
1
1
0
Freescale Semiconductor
LED drive
Optional
DDRB0
pullup
PTB0
Bit 0
Bit 0
0