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Originally Posted by Al Skierkiewicz
Isn't there a time mark on the dashboard port data stream?
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Yes, in a way. Each packet coming in to the RC (and leaving, for that matter) has a packet number associated with it. It's an 8-bit number that increments for each packet. There are 40 packets per second, so 1 bit in the packet number represents about 25 milliseconds. If your timing needs do not require high accuracy and/or are very coarse (i.e. you want to do something every 500 milliseconds or something), this could be a simple way to do it. There are some gotchas, though: since it is an 8 bit number it does overflow about every 4 seconds which means if you do try to use it as a timer you'll have to handle that overflow. Also if a packet is corrupted or not received it will not be passed to the user processor, so if you have a bad radio link there will appear to be gaps in the packet numbers. If you take that all into account in your software though then it can have its uses. I think we may have used it as a rudimentary timer in our RC last year ourselves.