[smayes]

I did follow the "autobaudconfigandstore" instructions, but didn't seem to gain anything. I can confirm baud rate tomorrow, but I believe it's 57600.

Where can I find the OPUploadTool?

Even if the baud rate was wrong I should still see some data on the Tx line with the scope, but there's nothing there (GPS only mode does show data on the scope).

I would try to diagnose a hardware issue, but I can't really do that without a schematic or net-list. Is there a chance that information is floating around?

[TheOtherCliff]

Where can I find the OPUploadTool?

Good question.  I recall there is a build problem with it, but maybe not back in 16.09

Even if the baud rate was wrong I should still see some data on the Tx line with the scope, but there's nothing there (GPS only mode does show data on the scope).

Well, I think that leaves out the baud rate as an issue, the mag data should be there at least.  Last hope would be reflashing the MCU.

I would try to diagnose a hardware issue, but I can't really do that without a schematic or net-list. Is there a chance that information is floating around?

A schematic was apparently never released.  There are one or two people who make them (for like $100).

First trace the TxD line back to the MCU and see if you see data there, but not on the connector pin.  That might be a simple fix.  I think that SBL running puts data on TxD without being prompted from RxD, but it's just a guess.  You could put a solder blob across SBL (system boot loader) and see if you then see output (using the scope) on the MCU pin with the SBL active.  If so, you can try flashing firmware.  If not, best hope might be replacing the MCU then flashing.

[f5soh]

I did follow the "autobaudconfigandstore" instructions, but didn't seem to gain anything.

As expected, GPS is connected to the MCU using I2C.

A schematic was apparently never released.

https://forum.librepilot.org/index.php?topic=4274.msg29087#msg29087

If orange led is blinking, MCU works fine. Issue will be between MCU and GPS+MCU port and will cause problems also for flashing.
Anyway, stm32flash can be used for flashing.
As well as Uploadtool, using next branch.

[smayes]

Thank you! That's what I needed.

There's definitely a signal coming off the MCU (not as clean as I was expecting, but I'm also not using the best measurement setup) and that signal is getting to the filter, but there's nothing on the output pin of the filter. I'll see if I can order a new one and swap it out?

[TheOtherCliff]

I think these filters are mainly to keep high voltages from the port.

I would be tempted to bypass the filter for the TxD line or (better yet in case the filter chip is shorted) remove filter chip and short input to output where the chip was mounted (both for TxD and again for RxD).  CC3D doesn't even use a filter there (Revo does, so you have a filter already).  GPS, mag, Revo ports all are 3.3V.  Maybe be careful about using a 5V FTDI to program the GPS MCU though.  I think the MCU RxD pin is 5V tolerant, but I'm not 100% certain, I just go by what Google says.

[smayes]

After removing and bypassing the filter the aux mag was actually recognized and seemed to be working, but the GPS was still inop, so I decided to try to flash the firmware. I can't seem to get the UplaodTool to work.

The attached image shows the output I get each time I run the UploadTool with the GPS+MCU port being connected immediately after hitting return.

[TheOtherCliff]

The filter chip has a separate filter for TxD and another for RxD, so you must make two jumpers in place of the chip.  I guess you did that?

The FTDI (USB to serial converter) needs to stay plugged in.  You plug and unplug the FTDI to GPS+MCU connection.

Try different timing, for instance maybe plugging it in just before hitting return.

There is another way to flash, using SBL.  I think instructions would be the same as for CC3D (but not Revo).
This:
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/29622291/Recover+board+using+DFU
Points to this for CC3D:
http://www.southquay3d.com/index.php?route=news/article&news_id=9

[smayes]

Yes I added jumpers to both. I was using the Revo ComBridge to communicate with the GPS (I have a FTDI coming soon), but I was plugging/un-plugging the GPS to Revo connection in different timing combinations.

Not sure if DFU should work over ComBridge, but I tried it without success according to the CC3D instructions. The green LED is solid with the SBL pads jumped so it looks like it's in the right mode.

[TheOtherCliff]

You have to set the ComBridge baud rate with the GCS.  If the program talking to the ComBridge tries to change the baud rate, the baud rate change gets ignored as I recall.

I work with Linux.  I recall some permission issues.  It may not have been with ComBridge.

[smayes]

Turns out bypassing the filter was the whole fix. I just had to set the autoconfig while connected with GPS+MCU port connected and now it's working! I'll probably still have some questions about getting the firmware to flash. I'd like to get rid of the dropped packet bug.