Справочник Пользователя для Motorola MC68HC908MR16
Advance Information
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
316
Input/Output (I/O) Ports
MOTOROLA
Input/Output (I/O) Ports
15.6 Port D
Port D is a 7-bit, input-only port that shares its pins with the pulse width
modulator for motor control module (PMC).
modulator for motor control module (PMC).
The port D data register (PTD) contains a data latch for each of the
seven port pins.
seven port pins.
PTD[6:0] — Port D Data Bits
These read/write bits are software programmable. Reset has no
effect on port D data.
effect on port D data.
Figure 15-12. Port D Input Circuit
Reading address $0003 reads the voltage level on the pin.
summarizes the operation of the port D pins.
Address:
$0003
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
PTD6
PTD5
PTD4
PTD3
PTD2
PTD1
PTD0
Write:
R
R
R
R
R
R
R
R
Reset:
Unaffected by reset
R
= Reserved
Figure 15-11. Port D Data Register (PTD)
Table 15-4. Port D Pin Functions
PTD Bit
Pin Mode
Accesses to PTD
Read
Write
X
(1)
1. X = don’t care
Input, Hi-Z
(2)
2. Hi-Z = high impedance
Pin
PTD[6:0]
(3)
3. Writing affects data register, but does not affect input.
READ PTD ($0003)
PTDx
IN
TE
RN
AL
DA
TA
BU
S