MC68HC908LJ12 Datasheet, PDF (355/413 Pages) Freescale Semiconductor, Inc – 8-bit microcontroller units

Input/Output (I/O) Ports
READ DDRD ($0007)
WRITE DDRD ($0007)
RESET
WRITE PTD ($0003)
READ PTD ($0003)
DDRDx
PTDx
PTDx
Figure 17-14. Port D I/O Circuit
When DDRDx is a logic 1, reading address $0003 reads the PTDx data
latch. When 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 17-5 summarizes the operation of the port D pins.
Table 17-5. Port D Pin Functions
DDRD
Bit
0
PTD Bit
X⁽¹⁾
I/O Pin
Mode
Input, Hi-Z⁽²⁾
Accesses
to DDRD
Read/Write
DDRD[7:0]
1
X
Output
DDRD[7:0]
Notes:
1. X = don’t care.
2. Hi-Z = high impedance.
3. Writing affects data register, but does not affect the input.
Accesses to PTD
Read
Pin
PTD[7:0]
Write
PTD[7:0]⁽³⁾
PTD[7:0]
Technical Data
356
Input/Output (I/O) Ports
MC68HC908LJ12 — Rev. 2.1
Freescale Semiconductor