Specifications

68
Interrupt Channels
16 system interrupt channels are provided by the NMI of the CPU and two 8259
interrupt controllers in the SIS-85C471-AT-Controller. All interrupts may be
masked. Interrupts are sorted by priority, starting with the highest priority. Table
16 lists all available interrupts:
Interrupt Level Function
NMi Parity or I/O error
Master Slave
IRQ 0 Timer Output 0
IRQ 1 Keyboard
IRQ 2 Cascading for slave controller
IRQ 8 Real-time clock (RTC)
IRQ 9 Software redirect to INT 0Ah
IRQ 10 available
IRQ 11 available
IRQ 12 available
IRQ 13 Co-processor
IRQ 14 Hard disk controller
IRQ 15 available
IRQ 3 COM2
IRQ 4 COM1
IRQ 5 available (LPT2)
IRQ 6 Floppy disk controller
IRQ 7 LPT1
Table 25, System Interrupt Levels
5.2