New member advice please

[BobM]

Hi
I am new to all of this but here goes

I am considering building a small PIC based project.
Original specs use a 16C84 microcontroller.
I am wondering what exactly is involved with migrating to a 16F628A.
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Second question.................
Original specs use an external 4MHz crystal.
Should one do away with that and use the internal 4MHz oscillator or (perhaps for stability reasons) should one stick with the original design?

If it is OK to use the internal oscillator could you show me the one-liner which chooses the 4MHz internal oscillator and explain exactly how to interpret the code

Many thanks
Bob
New Zealand

[Archangel]

Hello Bob in New Zealand, Welcome !
I have never used a 16C version, I have used a 16F84 however. The biggest thing I see is 16F628A has comparators on PortA, turn them off with CMCON = 7 . As fas as using INTOSC or XTAL, or a Resonator, depends upon how critical your timing needs are, if you are using serial outs you may not want to use INTOSC.
look at these threads:
http://www.picbasic.co.uk/forum/showthread.php?t=543
http://www.picbasic.co.uk/forum/showthread.php?t=561
JS

[BobM]

Thank's Joe