Motorola MC68HC908MR32 用户手册
Input/Output (I/O) Ports
Port F
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
Advance Information
MOTOROLA
Input/Output (I/O) Ports
321
Figure 15-18. Port F I/O Circuit
When bit DDRFx is a logic 1, reading address $0009 reads the PTFx
data latch. When bit DDRFx is a logic 0, reading address $0009 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit.
data latch. When bit DDRFx is a logic 0, reading address $0009 reads
the voltage level on the pin. The data latch can always be written,
regardless of the state of its data direction bit.
summarizes
the operation of the port F pins.
Table 15-6. Port F Pin Functions
DDRF
Bit
PTF
Bit
I/O Pin Mode
Accesses
to DDRF
Accesses to PTF
Read/Write
Read
Write
0
X
(1)
1. X = don’t care
Input, Hi-Z
(2)
2. Hi-Z = high impedance
DDRF[6:0]
Pin
PTF[6:0]
(3)
3. Writing affects data register, but does not affect input.
1
X
Output
DDRF[6:0]
PTF[6:0]
PTF[6:0]
READ DDRF ($000D)
WRITE DDRF ($000D)
RESET
WRITE PTF ($0009)
READ PTF ($0009)
PTFx
DDRFx
PTFx
IN
TE
RN
AL DAT
A BUS