PIC18F97J60 max external bus speed

I've just managed to get this device working with external flash memory. I don't have timing diagrams of the external read and write cycles for the PIC, so tough to say what max bus speed I can operate at. I did see a comment in AN869 that the ext. bus speed is limited to 25MHz.

Can anyone shed some light on this please?

Mariusv

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Originally Posted by mariusv

I don't have timing diagrams of the external read and write cycles for the PIC, so tough to say what max bus speed I can operate at. I did see a comment in AN869 that the ext. bus speed is limited to 25MHz.

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Internet connection works...otherwise you wouldn't have been able to post a question.

Is Microchip's website down?...otherwise you'd most likely be able to find the PIC18F97J60 datasheet possibly by searching for PIC18F97J60, or you might even click on this link:
http://www.microchip.com/stellent/id...cName=en026439
But since you've come this far and as you say, you have an example working with external flash memory, I think I can safely assume you know this already. I got the answer in less than a minute (excluding the download of the entire datasheet).

Thanks for your wonderful help, Skimask.

I did find the datasheets, and it seems that the address valid to valid data time constraint was the most severe requirement. Using 70ns flash devices, I calculated that I could use a bus speed of 31.5MHz. However, the datasheet states that a bus speed of 25MHz should be used with external program memory.

Has anyone done similar calcs?

Thanks in advance
Mariusv

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Originally Posted by mariusv

However, the datasheet states that a bus speed of 25MHz should be used with external program memory.

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I can't find that 'requirement' in the datasheets.
Where are you seeing that?