gnupic: Re: [gnupic] Re: [orders] Re: [gnupic] gpasm hex files, compatibility with odyssey
Subject:
Re: [gnupic] Re: [orders] Re: [gnupic] gpasm hex files, compatibility with odyssey
From:
Robert Pearce ####@####.####
Date:
29 May 2007 21:01:39 +0100
Message-Id: <XHTbfxKYZIXGFw4s@daniel.huneausware.local>
On Tue, 29 May 2007, Tim Allen ####@####.#### wrote :
>Now that you mention it reading a blank chip and writing it back is not
>a good test. I will have to dig in to the Odyssey source to see what's
>really going on.
Another thought occurred to me just after posting...
The PIC ICSP protocol is master-slave, and has the rather unfortunate
characteristic that if you implement only the minimum it is possible to
have no device present and still pass that test!
If you have access to a 'scope it would be well worth looking at the
voltages on your PIC pins during a programming attempt. You need Vss at
+5V and Vpp at +12V (ideally more like +14V if you ever want to use a
ROM device). You also need to see clock and data signals (toggling from
0V to 5V) on RB6 and RB7.
--
Rob Pearce http://www.bdt-home.demon.co.uk
The contents of this | Windows NT crashed.
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