MC68HC08AS32 Datasheet, PDF (148/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

READ DDRD ($0007)
WRITE DDRD ($0007)
RESET
WRITE PTD ($0003)
DDRDx
PTDx
PTDx
READ PTD ($0003)
Figure 11-13. 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 11-4 summarizes the operation of the port D pins.
Table 11-4. Port D Pin Functions
DDRD PTD Bit in Use
Bit
Bit
by ADC
I/O Pin
Mode
Accesses to
DDRD
Read/Write
0
X
No
Input, Hi-Z DDRD[6:0]
1
X
No
Output
DDRD[6:0]
0
X
Yes
Input, Hi-Z DDRD[6:0]
1
X
Yes
Input, Hi-Z DDRD[6:0]
X = Don’t Care
Hi-Z = High Impedance
1. Writing affects data register, but does not affect input.
Accesses to PTD
Read
Pin
PTD[6:0]
0
PTD[6:0]
Write
PTD[6:0]⁽¹⁾
PTD[6:0]
PTD[6:0]⁽¹⁾
PTD[6:0]
Data Sheet
148
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor