To implement interrupt driven communication, the signals COMMRX and COMMTX must be factored into any interrupt controller being used. If no interrupt controller is being used, the signals can be applied to a NOR gate with the output driving nIRQ.

When an interrupt occurs, the program must examine the Debug Comms Control register to determine if an event occurred. If the W bit is clear, new data can be written into the Debug Comms Write register. If the R bit is set, new data has been received and can be read.

If the W bit is set and the R bit clear, the Debug Comms channel was not the source of the interrupt.