section 7 - Index of

STOP Stop Instruction Processing STOP,Operation:Enter the stop processing state andstop the clock oscillatorAssembler Syntax:STOPDescription: Enter the STOP processing state. All activity in the processor is suspendeduntil the RESET or IRQA pin is asserted. The clock oscillator is gated off internally. TheSTOP processing state is a low-power standby state.During the STOP state, port A is in an idle state with the control signals held inactive (Le.,RD=WR=Vcc etc.), the data pins (DO-D23) are high impedance, and the address pins(A 1-A 15) are unchanged from the previous instruction. If the bus grant was assertedwhen the STOP instruction was executed, port A will remain three-stated until the DSPexits the STOP state.If the exit from the STOP state was caused by a low level on the RESET pin, then theprocessor will enter the reset processing state. The time to recover from the STOP stateusing RESET will depend on the oscillator used. Consult the DSP56001 Advance InformationData Sheet (ADI1290) for details.If the exit from the STOP state was caused by a low level on the IRQA pin, then the processorwill service the highest priority pending interrupt and will not service the IRQAinterrupt unless it is highest priority. The interrupt will be serviced after an internal delaycounter counts 65,536 clock cycles (or a three clock cycle delay if the stop delay bit inthe OMR is set to one) plus 17T (see the DSP56001 Technical Data Sheet (ADI1290) fordetails). During this clock stabilization count delay, all peripherals and external interruptsare cleared and re-enabled/arbitrated at the start of the 17T period following the countinterval. The processor will resume program execution at the instruction following theSTOP instruction that caused the entry into the STOP state after the interrupt has beenserviced or, if no interrupt was pending, immediately after the delay count plus 17T. If theIRQA pin is asserted when the STOP instruction is executed, the clock will not be gatedoff, and the internal delay counter will be started.