Specifications

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2-1. INTERRUPT MAP
The equivalent of two 8259 Programmable Interrupt Controllers (PIC) are included on the AR-B1570
board. They accept requests from peripherals, resolve priorities on pending interrupts in service, issue
interrupt requests to the CPU, and provide vectors which are used as acceptance indices by the CPU to
determine which interrupt service routine to execute. These two controllers are cascaded with the
second controller representing IRQ8 to IRQ15, which is rerouted through IRQ2 on the first controller.
The following is the system information of interrupt levels:
IRQ2
Interrupt Level Description
NMI Parity check
CTRL1
IRQ0
IRQ1
System timer interrupt from timer 8254
keyboard output buffer full
Rerouting to IRQ8 to IRQ15
CTRL2
IRQ8:Real time clock
IRQ9:Reserved
IRQ10:LAN adapters(based on PCI INT routing)
IRQ12:Reserved for PS/2 mouse
IRQ13:Math.Co-processor
IRQ14:Hard disk adapter
IRQ3 Serial port(depends on setup assignment)
IRQ4 Serial port(depends on setup assignment)
IRQ5 Reserved
IRQ6 Reserved for floppy disk adapter
IRQ7 Parallel port 1
IRQ15:Hard disk adapter
Interrupt Controller