MC68HC908JL3E Datasheet, PDF (161/226 Pages) Motorola, Inc – Microcontrollers

Input/Output (I/O) Ports
Port D
READ DDRB ($0005)
WRITE DDRB ($0005)
RESET
WRITE PTB ($0001)
DDRBx
PTBx
PTBx
READ PTB ($0001)
To Analog-To-Digital Converter
Figure 12-8. Port B I/O Circuit
When DDRBx is a logic 1, reading address $0001 reads the PTBx data
latch. When DDRBx is a logic 0, reading address $0001 reads the
voltage level on the pin. The data latch can always be written, regardless
of the state of its data direction bit. Table 12-3 summarizes the operation
of the port B pins.
Table 12-3. Port B Pin Functions
DDRB Bit
0
PTB Bit
X⁽¹⁾
I/O Pin Mode
Input, Hi-Z⁽²⁾
Accesses to DDRB
Read/Write
DDRB[7:0]
Accesses to PTB
Read Write
Pin PTB[7:0]⁽³⁾
1
X
Output
DDRB[7:0]
Pin PTB[7:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect the input.
12.5 Port D
Port D is an 8-bit special function port that shares two of its pins with
timer interface module, (see Section 10.) and shares four of its pins with
analog-to-digital converter module (see Section 11.). PTD6 and PTD7
each has high current drive (25mA sink) and programmable pull-up.
PTD2, PTD3, PTD6 and PTD7 each has LED driving (sink) capability.
NOTE: PTD0–PTD1 are available on MC68H(R)C908JL3E only.
MC68H(R)C908JL3E/JK3E/JK1E — Rev. 2.0
MOTOROLA
Input/Output (I/O) Ports
Technical Data
161