Tony,

Going from a little 8 pin PIC to a 40 pin one doesn't make a whole lot of
sense if all you need is code checksumming/CRC.

The smallest PIC I know of that can read its own program memory is the 28
pin versions of the 16G87x family.

Bob Ammerman
RAm Systems


----- Original Message -----
From: "Tony Pan" <weidong.pan@VERIZON.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, August 12, 2002 5:48 PM
Subject: Re: [PIC] How to do a RAM check?


> Thank all for helping me at the thread "How to do CRC on the ROM?" I am
> considering using 16C662 and its feature Parity Error Reset (PER). Maybe
UL
> can accept that? I will ask.
>
> Meanwhile, I need to do a RAM check.
>
> I already know that I need to scan the RAM, write 0xAA and read back;
write
> 0x55 and read back to varify the integraty of the RAM. But I don't know
how
> and when to use that in the code. Do I need to test the whole RAM memory
at
> the same time? Or one word at a time during different operation of the
> software? I also read from somewhere that due to the consitently changing
> nature of the RAM, I cannot use C to do it. Yet, someone tell me I still
can
> as long as I am cautious and not to do something, etc.
>
> In other words, I am still not very clear how to do a RAM check.
>
> Can those who are more experienced give me a little guidance?
>
> A small piece of demo code will help greatly.
>
> Thanks!!!
>
> Tony
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>
>

--
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