149
Port 7 Data Register (P7DR)
Bit
Initial value
Read/Write
0
P7
—
R
*
Note: *
0
1
P7
—
R
*
1
2
P7
—
R
*
2
3
P7
—
R
*
3
4
P7
—
R
*
4
5
P7
—
R
*
5
6
P7
—
R
*
6
7
P7
—
R
*
7
7
0
Determined by pins P7 to P7 .
When port 7 is read, the pin logic levels are always read. P7DR cannot be modified.
7.5
Port 8
7.5.1
Overview
Port 8 is a 5-bit input/output port that is also used for
CS
3
to
CS
0
output,
IRQ
3
to
IRQ
0
input, and
A/D converter
ADTRG
input. Figure 7.4 shows the pin configuration of port 8.
In the H8/3008, port 8 can provide
CS
3
to
CS
0
output,
IRQ
3
to
IRQ
0
input, and
ADTRG
input. See
table 7.8 for the selection of pin functions in expanded modes.
See section 14, A/D Converter, for a description of the A/D converter’s
ADTRG
input pin.
The
IRQ
3
to
IRQ
0
functions are selected by IER settings, regardless of whether the pin is used for
input or output. Caution is therefore required. For details see section 5.3.1, External Interrupts.
Pins in port 8 can drive one TTL load and a 90-pF capacitive load. They can also drive a
darlington transistor pair.
Pins P8
2
to P8
0
have Schmitt-trigger inputs.
Port 8
P8 /
P8 / /
P8 / /
P8 / /
P8 /
4
3
2
1
0
0
1
2
3
Port 8 pins
CS
CS
CS
CS
3
2
1
IRQ
/
ADTRG
IRQ
IRQ
IRQ
0
P8 (input)/ (output)
P8 (input)/ (output)/ (input) /
ADTRG
(input)
P8 (input)/ (output)/ (input)
P8 (input)/ (output)/ (input)
P8 (input/output)/ (input)
4
3
2
1
0
0
1
2
3
CS
CS
CS
CS
3
2
1
IRQ
IRQ
IRQ
IRQ
0
Figure 7.4 Port 8 Pin Configuration
Содержание H8/3008
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