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17.6 Port D
17.6.1 Port D Data Register (PTD)
Alternative Function:
Additional Functions:
MC68HC908AB32
Rev. 1.0
—
MOTOROLA
Port D is an 8-bit special function port that shares two of its pins with the
timer interface module (see
(TIMA)
and
Section 12. Timer Interface Module B
port D pin has 15mA current drive (sink) and programmable pullup.
The port D data register contains a data latch for each of the eight port D
pins.
Address:
$0003
Bit 7
6
Read:
PTD7
PTD6
Write:
Reset:
TACLK
15mA sink 15mA sink 15mA sink 15mA sink 15mA sink 15mA sink 15mA sink 15mA sink
Input pullup Input pullup Input pullup Input pullup Input pullup Input pullup Input pullup Input pullup
Figure 17-11. Port D Data Register (PTD)
PTD[7:0] — Port D Data Bits
These read/write bits are software programmable. Data direction of
each port D pin is under the control of the corresponding bit in data
direction register D. Reset has no effect on port D data.
TACLK — Timer A Clock Input
The PTD6 pin becomes TACLK, the timer A (TIMA) external clock
input when the TIMA prescaler select bits, PS[2:0] = 111. See
Section 11. Timer Interface Module A
TBCLK — Timer B Clock Input
The PTD4 pin becomes TBCLK, the timer B (TIMB) external clock
input when the TIMB prescaler select bits, PS[2:0] = 111. See
Section 12. Timer Interface Module B
Input/Output (I/O) Ports
Section 11. Timer Interface Module A
5
4
3
PTD5
PTD4
PTD3
Unaffected by reset
TBCLK
(TIMA).
(TIMB).
Input/Output (I/O) Ports
Port D
(TIMB)). Each
2
1
Bit 0
PTD2
PTD1
PTD0
Technical Data
323
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