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Unread 08-03-2007, 15:09
yoyodyne yoyodyne is offline
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AKA: Greg Smith
FRC #0116 (Epsilon Delta)
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Camera problem Serial Port 2 Inserting Extra Null Bytes?

Hi All,

I saw a thread on the camera working correctly for longer after a power cycle and a mention by Kevin Watson that you might have to hold the reset switch on the RC? for 5 seconds but I can't seem to find those posts. Anyway, we are having the same problem. Last night, I captured the binary data from the RC to the CAMERA and from the camera to the RC and what I found was that a zero byte is inserted into the data stream from the RC to the camera every now and then. The camera NCK's and our code which was not expecting that times out on the ack and tries to re-initialize the camera which will struggle to get acks from the CR packets and finally get T packets coming again for about a second. We are putting the camera in polled mode [PM11] so that we can correlate the virtual window settings with the next T-packet returned from the camera.

Anyway, the attached file shows a binary dump of the traffic from the RC to the camera in a state where there is no target so no VW commands are sent, only TC packets each time the camera ACKs.

Notice that byte 885 and byte 1358 are inserted 0's. I was hoping that the delta would be some function of the serial port buffer size but 473 in this case is pretty strange. I guess I will collect more data tonigh - our second Fix-It-Window this week and see if I can find a correlation. The binary file was collected using TeraTerm. Any suggestions would be appreciated. Obviously I will be looking at the serial port driver and interrupt code. Oh, this is KW's 10-Jan-2006 serial code, I think the latest.
Attached Files
File Type: txt RC_TO_CAM.txt (13.1 KB, 24 views)