Techniques for Device Identification (2)
• Daisy Chain (Hardware poll, vectored)
—Interrupt Acknowledge sent down a chain through the modules
—Module responsible places vector (a word) on bus (data lines)
—CPU uses vector to identify handler routine
—Called vectored interrupt.
• Bus arbitration (vectored)
—Module must claim the bus before it can raise interrupt
—Module responsible places vector (a word) on bu