MC68HC908GT16 Datasheet, PDF (243/412 Pages) Motorola, Inc – Microcontrollers

READ DDRD ($0007)
WRITE DDRD ($0007)
RESET
WRITE PTD ($0003)
DDRDx
PTDx
Input/Output (I/O) Ports
Port D
V_DD
PTDPUEx
30 k
PTDx
READ PTD ($0003)
Figure 16-15. 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 16-5 summarizes
the operation of the port D pins.
Table 16-5. Port D Pin Functions
PTDPUE
Bit
DDRD PTD
Bit
Bit
I/O Pin
Mode
Accesses
to DDRD
Read/Write
1
0
X⁽¹⁾
Input, V_DD(2)
DDRD7–DDRD0
0
0
X
Input, Hi-Z⁽⁴⁾
DDRD7–DDRD0
X
1
X
Output
DDRD7–DDRD0
1. X = Don’t care
2. I/O pin pulled up to V_DD by internal pullup device.
3. Writing affects data register, but does not affect input.
4. Hi-Z = High imp[edance
Accesses
to PTD
Read
Write
Pin
PTD7–PTD0⁽³⁾
Pin
PTD7–PTD0⁽³⁾
PTD7–PTD0
PTD7–PTD0
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
MOTOROLA
Input/Output (I/O) Ports
Technical Data
243