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INTERRUPT CONTROL UNIT
9.3.2 Interrupt Configuration Register (INTCFG)
Use the INTCFG register to connect the INT9:4 interrupt request pins to the master’s and the
slave’s IR signals and to enable the master’s external cascade signals. When enabled, the cascade
signals appear on address lines A18:16 during interrupt acknowledge cycles. Every external slave
monitors these lines to determine whether it is the slave being addressed.
Figure 9-7. Interrupt Configuration Register (INTCFG)
Interrupt Configuration
INTCFG
(read/write)
Expanded Addr:
ISA Addr:
Reset State:
F832H
—
00H
7 0
CE IR3 IR4 SWAP IR6 IR5/IR4 IR1 IR0
Bit
Number
Bit
Mnemonic
Function
7 CE Cascade Enable:
0 = Disables the cascade signals CAS2:0 from appearing on the A18:16
address lines during interrupt acknowledge cycles.
1 = Enables the cascade signals CAS2:0, providing access to external
slave 82C59A devices. The cascade signals are used to address
specific slaves. If enabled, slave IDs appear on the A18:16 address
lines during interrupt acknowledge cycles, but are high during idle
cycles.
6 IR3 Internal Master IR3 Connection:
See Table 5-1 on page 5-8 for all the IR3 configuration options.
5 IR4 Internal Master IR4 Connection:
See Table 5-2 on page 5-8 for all the IR4 configuration options.
4 SWAP INT6/DMAINT Connection:
0 = Connects DMAINT to the slave IR4. Connects INT6 to the slave IR5.
1 = Connects the INT6 pin to the slave IR4. Connects DMAINT to the slave
IR5.
3 IR6 Internal Slave IR6 Connection:
0 = Connects V
SS
to the slave IR6 signal.
1 = Connects the INT7 pin to the slave IR6 signal.
2 IR5/IR4 Internal Slave IR4 or IR5 Connection:
These depend on whether INTCFG.4 is set or clear.
0 = Connects V
SS
to the slave IR5 signal.
1 = Connects either the INT6 pin or DMAINT to the slave IR5 signal.
1 IR1 Internal Slave IR1 Connection:
0 = Connects the SSIO interrupt signal (SSIOINT) to the slave IR1 signal.
1 = Connects the INT5 pin to the slave IR1 signal.
0 IR0 Internal Slave IR0 Connection:
0 = Connects V
SS
to the slave IR0 signal.
1 = Connects the INT4 pin to the slave IR0 signal.