MC68HC908GP20 Datasheet, PDF (239/406 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

READ DDRD ($0007)
WRITE DDRD ($0007)
RESET
WRITE PTD ($0003)
VDD
DDRDx
PTDx
PTDPUEx
READ PTD ($0003)
INTERNAL
PULLUP
DEVICE
PTDx
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
1
0
DDRD Bit
0
0
PTD Bit
X⁽¹⁾
X
I/O Pin Mode
Input, V_DD(4)
Input, Hi-Z⁽²⁾
Accesses to DDRD
Read/Write
DDRD7–DDRD0
DDRD7–DDRD0
Accesses to PTD
Read
Pin
Pin
Write
PTD7–PTD0⁽³⁾
PTD7–PTD0⁽³⁾
X
1
X
Output
DDRD7–DDRD0 PTD7–PTD0 PTD7–PTD0
Notes:
1. X = Don’t care
2. Hi-Z = High impedance
3. Writing affects data register, but does not affect input.
4. I/O pin pulled up to V_DD by internal pullup device.
MC68HC908GP20 — Rev 2.1
Freescale Semiconductor
Advance Information
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