Hardware manual

Rev. 3.0, 09/98, page 119 of 361
6.10 Port 9
Port 9 is an 8-bit input/output port that also provides pins for interrupt input (IRQ
0
to IRQ
2
), A/D
trigger input, system clock (φ) output, and bus control signals (in the expanded modes).
Pins P9
7
to P9
3
have different functions in different modes. Pins P9
2
to P9
0
have the same
functions in all modes. Table 6.21 lists the pin functions.
Table 6.21 Port 9 Pin Functions
Pin Expanded Modes Single-Chip Mode
P9
0
P9
0
input/output , IRQ
2
input, and ADTRG input (simultaneously)
P9
1
P9
1
input/output and IRQ
1
input (simultaneously)
P9
2
P9
2
input/output and IRQ
0
input (simultaneously)
P9
3
RD output P9
3
input/output
P9
4
WR output P9
4
input/output
P9
5
AS output P9
5
input/output
P9
6
φ output P9
6
input or φ output
P9
7
WAIT input P9
7
input/output
Pins of port 9 can drive a single TTL load and a 90pF capacitive load when they are used as output
pins.
Table 6.22 details the port 9 registers.
Table 6.22 Port 9 Registers
Name Abbreviation Read/Write Initial Value Address
Port 9 data direction register P9DDR W H'40 (modes 1 and 2)
H'00 (mode 3)
H'FFC0
Port 9 data register P9DR R/W
*
1
Undetermined
*
2
H'FFC1
Notes: 1. Bit 6 is read-only.
2. Bit 6 is undetermined. Other bits are initially “0.”