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Port 7 Data Register (P7DR)
Bit
Initial value
Read/Write
Note: *
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
A/D converter ADTRG input. Figure 7.4 shows the pin configuration of port 8.
In the H8/3008, port 8 can provide CS
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
to IRQ
functions are selected by IER settings, regardless of whether the pin is used for
3
0
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
to P8
have Schmitt-trigger inputs.
2
0
Port 8
7
6
P7
P7
7
6
—
*
—
*
R
R
7
0
to CS
3
Port 8 pins
CS
P8 /
4
0
CS
IRQ / ADTRG
P8 /
/
3
1
3
CS
IRQ
P8 /
/
2
2
2
CS
IRQ
P8 /
/
1
3
1
IRQ
P8 /
0
0
Figure 7.4 Port 8 Pin Configuration
5
4
P7
P7
P7
5
4
—
*
—
*
R
R
to CS
3
output, IRQ
to IRQ
0
3
CS
P8 (input)/
4
0
CS
P8 (input)/
3
1
CS
P8 (input)/
2
2
CS
P8 (input)/
1
3
P8 (input/output)/
0
3
2
P7
P7
3
2
—
*
—
*
R
R
output, IRQ
to IRQ
0
3
input, and ADTRG input. See
0
(output)
IRQ
(input) / ADTRG (input)
(output)/
3
IRQ
(output)/
(input)
2
IRQ
(output)/
(input)
1
IRQ
(input)
0
1
0
P7
1
0
—
*
—
*
R
R
input, and
0
149
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