68HC11 Asm - Hand Assembly

May 15, 2005 4 Replies
M

Hi,



I am writing to ask if anyone knows how to hand assemble a simple



68HC11 program? My problem is getting the op code. I am using the standard instruction set. I know that you have to count the number of CPU cycles for each instruction.

Does anybody know of a good tutorial on this?



Thanks, Mickey



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L

You need to know the number of bytes for each instruction, not the number of clock cycles, so that you can write down the address of each instruction. Why not use an assembler, it's much easier?

Leon

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S

Read this:

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Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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P

I have always found the Leventhal books very good on such topics. However, if you already have the instruction set to hand (in the datasheets for the processor) you just need to take note of how many bytes each instruction occupies so that you can calculate the next instruction addresses. Be sure to count the negative direction properly too (when doing jumps back to the start of a loop).

******************************************************************** Paul E. Bennett .................... Forth based HIDECS Consultancy ..... Mob: +44 (0)7811-639972 Tel: +44 (0)1235-811095 Going Forth Safely ....EBA. http://www.electric-boat-association.org.uk/********************************************************************
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P

Hi, try this for assembly and testing (free HC11 simulator):

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Regards Peter

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