Datasheet

652
19.3 Port B
Port B is a 10-pin input/output port as listed in table 19.5.
Table 19.5 Port B
ROM Disabled Extended
Mode (Modes 0, 1)
ROM Enabled Extended
Mode (Mode 2) Single Chip Mode
PB9 (I/O)/IRQ7 (input)/A21
(output)/ADTRG (input)
PB9 (I/O)/IRQ7 (input)/A21
(output)/ADTRG (input)
PB9 (I/O)/IRQ7 (input)/ADTRG
(input)
PB8 (I/O)/IRQ6 (input)/A20
(output)/WAIT (input)
PB8 (I/O)/IRQ6 (input)/A20
(output)/WAIT (input)
PB8 (I/O)/IRQ6 (input)
PB7 (I/O)/IRQ5 (input)/A19
(output)/BREQ (input)
PB7 (I/O)/IRQ5 (input)/A19
(output)/BREQ (input)
PB7 (I/O)/IRQ5 (input)
PB6 (I/O)/IRQ4 (input)/A18
(output)/BACK (output)
PB6 (I/O)/IRQ4 (input)/A18
(output)/BACK (input)
PB6 (I/O)/IRQ4 (input)
PB5 (I/O)/IRQ3 (input)/POE3
(input)/RDWR (output)
PB5 (I/O)/IRQ3 (input)/POE3
(input)/RDWR (output)
PB5 (I/O)/IRQ3 (input)/POE3
(input)
PB4 (I/O)/IRQ2 (input)/POE2
(input)/CASH (output)
PB4 (I/O)/IRQ2 (input)/POE2
(input)/CASH (output)
PB4 (I/O)/IRQ2 (input)/POE2
(input)
PB3 (I/O)/IRQ1 (input)/POE1
(input)/CASL (output)
PB3 (I/O)/IRQ1 (input)/POE1
(input)/CASL (output)
PB3 (I/O)/IRQ1 (input)/POE1
(input)
PB2 (I/O)/IRQ0 (input)/POE0
(input)/RAS (output)
PB2 (I/O)/IRQ0 (input)/POE0
(input)/RAS (output)
PB2 (I/O)/IRQ0 (input)/POE0
(input)
A17 (output) PB1 (I/O)/A17 (output) PB1 (I/O)
A16 (output) PB0 (I/O)/A16 (output) PB0 (I/O)
19.3.1 Register Configuration
Table 19.6 summarizes the port B register.
Table 19.6 Port B Register
Name Abbreviation R/W Initial Value Address Access Size
Port B data register PBDR R/W H'0000 H'FFFF8390
H'FFFF8391
8, 16, 32