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ModeratorPermalink Reply by Chris Anderson on June 10, 2009 at 6:57pm

You mean data telemetry for the groundstation?

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ModeratorPermalink Reply by James Cohen on June 11, 2009 at 12:53am

I do

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ModeratorPermalink Reply by Chris Anderson on June 11, 2009 at 6:10am

It's not clear to me that you'd get any performance improvement. The serial TX is handled by the hardware (UART) and we're well below the Xbee transmission capacity. It's also just not that much data--approx 1/5h as much as is coming in on the Rx side from the GPS.

I generally fall into the "if it ain't broke don't fix it" camp, and unless we can see some bottlenecking on the Tx side I wouldn't want to establish a new data standard and have to write new parsers for the onboard and ground sides.

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ModeratorPermalink Reply by James Cohen on June 11, 2009 at 6:57am

It only sprang to mind when I read a comment somewhere here within the community (I can't find it for love nor money now) that they'd experienced better performance by disabling the serial output.

From a quick look at the atmega datasheets I think that the transmission of each byte is done in the background by the USART system but that the buffer for USART transmission is just one byte. As soon as it empties this buffer the USART system triggers an interrupt which is caught by the arduino Serial library and submits the next byte into the buffer for transmission. It's could well be the case that the time the Serial library interrupt work takes up (it's just a few ops here and there) is negligible though it could all add up.

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