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How do I program the 68HC11 Microcontroler to use time delays.?

Here is an example of the code I need to use

DELAY LDX #$FFFF

More: DEX

NOP

NOP

NOP

NOP

BNE More

RTS

That is an example the teacher gave me for a time delay of about one second. I need to know how to the number $FFFF was determined.

1 Answer

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  • Sol
    Lv 4
    1 decade ago
    Favorite Answer

    It depends on your processor speed. You need to figure out how many clock cycles your code takes (off the top of my head, I think the NOP command is 3, but you'd have to check an OPCODE sheet), and then using the processor speed (1 MHz or whatever), you can figure out how many clock cycles need to occur to creat a 1 ms delay or whatever, and then you can just cycle down from, in this case $FFFF down to $0 to cause the delay.

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