MC908JB16DWE Datasheet, PDF (274/332 Pages) Freescale Semiconductor, Inc – Microcontrollers

Input/Output (I/O) Ports
READ DDRD ($0007)
WRITE DDRD ($0007)
RESET
WRITE PTD ($0003)
READ PTD ($0003)
DDRDx
PTDx
PTDx
Figure 14-10. Port D I/O Circuit
When bit DDRDx is a logic 1, reading address $0003 reads the PTDx
data latch. When bit DDRDx is a logic 0, reading address $0003 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit. Table 14-4 summarizes
the operation of the port D pins.
Table 14-4. Port D Pin Functions
DDRD
Bit
PTD Bit
I/O Pin Mode
Accesses
to DDRD
Read/Write
0
X⁽¹⁾
Input, Hi-Z^{(2) DDRD[5:0]}
1
X
Output
DDRD[5:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect input.
Accesses to PTD
Read
Pin
PTD[5:0]
Write
PTD[5:0]⁽³⁾
PTD[5:0]
Technical Data
274
Input/Output (I/O) Ports
MC68HC908JB16 — Rev. 1.1
Freescale Semiconductor