MC68HC908RK2 Datasheet, PDF (178/232 Pages) Motorola, Inc – Microcontroller Unit

Input/Output (I/O) Ports
13.4 Port B
Port B is a 6-bit special function port that shares three of its pins with the
timer (TIM) module and one with the buffered internal bus clock MCLK.
13.4.1 Port B Data Register
The port B data register (PTB) contains a data latch for each of the six
port B pins.
Address: $0001
Bit 7
6
5
4
3
2
1
Bit 0
Read:
Write:
PTB5 PTB4 PTB3 PTB2 PTB1 PTB0
Reset:
Unaffected by reset
Alternate
Functions:
TCH1 TCLK TCH0
MCLK
Advance Information
178
= Unimplemented
Figure 13-5. Port B Data Register (PTB)
PTB[5:0] — Port B Data Bits
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.
TCH1 — Timer Channel I/O Bit
The PTB4/TCH1 pin is the TIM channel 1input capture/output
compare pin. The edge/level select bits, ELS1B:ELS1A, determine
whether the PTB4/TCH1 pin is a timer channel I/O or a general-
purpose I/O pin. See Section 15. Timer Interface Module (TIM).
TCH0 — Timer Channel I/O Bit
The PTB2/TCH0 pin is the TIM channel 0 input capture/output
compare pin. The edge/level select bits, ELS0B:ELS0A, determine
whether the PTB2/TCH0 pin is a timer channel I/O or a general-
purpose I/O pin. See Section 15. Timer Interface Module (TIM).
Input/Output (I/O) Ports
MC68HC908RK2 — Rev. 4.0
MOTOROLA