Table of Contents
8.6
Port 9
8.6.1
Overview
Port 9 is a 6-bit input/output port that is also used for input and output (TxD
) by serial communication interface channels 0 and 1 (SCI0 and SCI1), and for IRQ
SCK
, SCK
0
1
and IRQ
input. See table 8.10 for the selection of pin functions.
4
The IRQ
and IRQ
functions are selected by IER settings, regardless of whether the pin is used
5
4
for input or output. Caution is therefore required. For details see section 5.3.1, External Interrupts.
Port 9 has the same set of pin functions in all operating modes. Figure 8.5 shows the pin
configuration of port 9.
Pins in port 9 can drive one TTL load and a 30-pF capacitive load. They can also drive a
darlington transistor pair.
Port 9
Port 9 pins
P9 (input/output)/SCK
5
P9 (input/output)/SCK
4
P9 (input/output)/RxD (input)
3
P9 (input/output)/RxD (input)
2
P9 (input/output)/TxD (output)
1
P9 (input/output)/TxD (output)
0
Figure 8.5 Port 9 Pin Configuration
, TxD
0
(input/output)/IRQ (input)
1
5
(input/output)/IRQ (input)
0
4
1
0
1
0
, RxD
, RxD
,
1
0
1
5
257
Table of Contents
