>-----Original Message-----
>From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] 
>Sent: 17 May 2005 19:45
>To: Microcontroller discussion list - Public.
>Subject: RE: [PIC]: PIC18F at 44.5MHz. Anybody has experiences 
>to share?
>
>
>I've noticed that the smaller 18F parts are rated at 40 MHz, 
>but the larger ones are not. My guess is that the larger ones 
>have more peripherals hanging on the internal bus, making it 
>hard to move the bus that fast.  Does my guess sound 
>reasonable? When I first started with one of the big 18F 
>chips, the datasheet said 40 MHz. My prototype worked, but 
>production didn't. A piclist member pointed out an erratta 
>dropping the clock speed to something like 25MHz.

The problem was in the larger memory parts.  Apparently the larger
arrays were prone to reflections/ringing on the busses causing data
corruption.

Regards

Mike

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