MC908JL8CDWE Datasheet, PDF (157/212 Pages) Freescale Semiconductor, Inc – Microcontrollers

READ DDRB ($0005)
WRITE DDRB ($0005)
RESET
WRITE PTB ($0001)
DDRBx
PTBx
Port D
PTBx
READ PTB ($0001)
To Analog-To-Digital Converter
Figure 11-9. 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 11-3 summarizes the operation of the port B pins.
Table 11-3. 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]
1
X
Output
DDRB[7:0]
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect the input.
Accesses to PTB
Read
Pin
Write
PTB[7:0]⁽³⁾
PTB[7:0] PTB[7:0]
11.4 Port D
Port D is an 8-bit special function port that shares two of its pins with the serial communications interface
module (see Chapter 9), two of its pins with the timer 1 interface module, (see Chapter 8), and four of its
pins with the analog-to-digital converter module (see Chapter 10). PTD6 and PTD7 each has high current
sink (25mA) and programmable pull-up. PTD2, PTD3, PTD6 and PTD7 each has LED sink capability.
NOTE
PTD0–PTD1 are available on 28-pin and 32-pin packages only.
MC68HC908JL8/JK8 • MC68HC08JL8/JK8 • MC68HC908KL8 Data Sheet, Rev. 3.1
Freescale Semiconductor
157