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read/write to internal registers?

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New Member
hi all,
Could you please show me how to read/write to internal registers such as Timer, HIGH/LOW-VOLTAGE DETECT(HLVD) register for pic18f4550? Thank you a lot.


New Member
I wonder which compiler ur using. Assuming it is the C18 or some other C compiler all U need to do is jus write
TMRO=0x00; writes 00 in hex to TMRO SFR
similarly U can do with all other SFRS provided that U have already included the ehader file having the details of all other SfRs in ur PROJECT worksapace.


Coop Build Coordinator
Forum Supporter
He could even be using an assembler.

The registers are defined by a processor definition file. In asm it would be an include file like processorName.inc. In C it is a header file , for C18 it would be processorName.h.

The register names and how to access them are determined by these file. Study them.


Active Member
I'm using CCS C compiler. How would I read/write? Thanks
Sorry, I'm new to this thing.
Take a look at the header file for your PIC. You should find you can set it very simply as long as you know the correct name.

The file will be named something like 18f1320.h

You could also check this page (or their examples).
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