CH6 - or RTI command This command returns control to back...

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Rick Wagoner IET645 – Spring 2006 Chapter 6 Exercises E6-1. What is the name given to a routine that is executed in response to an interrupt? Interrupt Service Routine. E6-2. What are the advantages of using interrupts to handle data inputs and outputs? The interrupt frees the CPU during I/O operations to perform other functions greatly improving system efficiency. E6-6. Write the assembler directives to initialize the IRQ interrupt vector located at $E200. ORG $E200 FDB IRQ_ISR CLI E6-7. What is the last instruction in most interrupt service routines? What does this instruction do? The last instruction in most interrupt service routines is the ‘return from interrupt’
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Unformatted text preview: or RTI command. This command returns control to back to the main program that is was called from if possible and restores Accumulators A and B, index registers X and Y, the program counters, and condition code register from the stack. The X bit of the CCR register may be cleared as a result of the command. E6-12. Why does the 68HC11 need to be reset when the power supply is too low? Low power supply requires a reset to ensure that EEPROM is not corrupted. This also ensures that voltage is at proper levels before letting the unit power back on....
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