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Unread 08-02-2008, 23:56
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Nathan Nathan is offline
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Re: printf() inside interrupt routine?

usbcd36 - I was debugging my driver and wanted to be able to see every byte printed out in the order it arrived. Eventually I discovered this was not possible to do because of how blazingly fast the camera sends tracking data.

So I am essentially doing what you suggest, storing the values and printing out a select few in the slow loop.

Before today I was completely unaware of how processor intensive a printf statement is. I have a blinking LED that's supposed to blink every 250 loops in the fast loop (which is around 250ms) and it works. But when I have even ONE printf statement in the fast loop it slows down to around one blink per second. So ONE printf statement slowed the program down by about a factor of 4! The IFI people weren't kidding when they insctructed in the manual to use only short printf statements for debugging!

Thanks,
Nathan
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