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7.9
Port 8
7.9.1
Overview
Port 8 is a 5-bit input/output port that is also used for CS
A/D converter ADTRG input. Figure 7.8 shows the pin configuration of port 8.
In modes 1 to 5 (expanded modes), port 8 can provide CS
ADTRG input. See table 7.14 for the selection of pin functions in expanded modes.
In modes 6 and 7 (single-chip modes), port 8 can provide IRQ
See table 7.15 for the selection of pin functions in single-chip mode.
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
186
Port 8 pins
P8 /
CS
4
0
P8 /
CS
/
IRQ / ADTRG
3
1
3
P8 /
CS
/
IRQ
2
2
2
P8 /
CS
/
IRQ
1
3
1
P8 /
IRQ
0
0
Pin functions in modes 6 and 7
(single-chip mode)
P8 /(input/output)
4
P8 /(input/output)/
IRQ
3
P8 /(input/output)/
IRQ
2
P8 /(input/output)/
IRQ
1
P8 /(input/output)/
IRQ
0
Figure 7.8 Port 8 Pin Configuration
to CS
3
to CS
3
Pin functions in modes 1 to 5
(expanded modes)
P8 (input)/
CS
4
0
P8 (input)/
CS
3
1
P8 (input)/
CS
2
2
P8 (input)/
CS
1
3
P8 (input/output)/
0
(input) /
ADTRG (input)
3
(input)
2
(input)
1
(input)
0
output, IRQ
to IRQ
0
3
output, IRQ
to IRQ
0
3
to IRQ
input and ADTRG input.
3
0
(output)
(output)/
IRQ
(input) / ADTRG (input)
3
(output)/
IRQ
(input)
2
(output)/
IRQ
(input)
1
IRQ
(input)
0
input, and
0
input, and
0
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