mc68hc908lj24 Freescale Semiconductor, Inc, mc68hc908lj24 Datasheet - Page 383

• Manufacturer Part Number: mc68hc908lj24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

18.4 Port B
18.4.1 Port B Data Register (PTB)
MC68HC908LJ24/LK24 — Rev. 2.1
Freescale Semiconductor
Alternative Function:
Additional Function:
Address:
Port B is a 8-bit special function port that shares two of its port pins with
the infrared serial communication interface (IRSCI) module, two of its
port pins with the timer interface module 1 (TIM1) module, two of its port
pins with the timer interface module 2 (TIM2), and two of its port pins with
the ADC module.
Port pins PTB0–PTB5 can be configured for direct LED drive.
The port B data register contains a data latch for each of the eight port B
pins.
PTB[7:0] — Port B Data Bits
TxD, RxD — SCI Data I/O Pins
Reset:
Read:
Write:
These read/write bits are software programmable. Data direction of
each port B pin is under the control of the corresponding bit in data
direction register B. Reset has no effect on port B data.
The TxD and RxD pins are the transmit data output and receive data
input for the IRSCI module. The enable SCI bit, ENSCI, in the SCI
control register 1 enables the PTB0/TxD and PTB1/RxD pins as SCI
TxD and RxD pins and overrides any control from the port I/O. See
Section 13. Infrared Serial Communications Interface Module
(IRSCI).
$0001
ADC5
PTB7
Bit 7
Figure 18-5. Port B Data Register (PTB)
Input/Output (I/O) Ports
ADC4
PTB6
6
LED drive LED drive LED drive LED drive LED drive LED drive
T2CH1
PTB5
5
Unaffected by reset
T2CH0
PTB4
4
T1CH1
PTB3
3
T1CH0
PTB2
2
Input/Output (I/O) Ports
PTB1
RxD
1
Data Sheet
PTB0
Bit 0
TxD
Port B
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