I am not sure what you are asking. I read the binary data from the com port and fed it right into a binary file. I didn’t manipulate it at all.
Correct, there was no VTX present. I recorded the data using a FTDI FT232R. I used a script in powershell on my windows laptop to capture and save the data.
Just not sure that’s going to be useful if there is any timing issue involved…
that is correct, I agree with Andy.
I hacked together a quick protocol decoder and both bin files contain valid displayport data up to the checksums
Well that is good to know. Now getfpv is saying that they won’t exchange it unless I can show it is defective.
How would we troubleshoot a timing issue?
Really need to see a Saleae trace
Just want to write a quick note to keep those watching this thread updated. @andyp1per was kind enough to do a test with his walksnail VTX and the Zealot H743. He confirmed what I was experiencing in that he was also NOT seeing the OSD Displayport through the Walksnail VTX.
So at least we can reproduce it. Now we need to determine if it is the FC or the VTX.
Here is another update to this thread on my OSD DisplayPort issues with the walksnail VTX. @andyp1per put the UART port of his QioTek Zealot H743 on a logic analyzer and found that he low voltage on the serial port was +1 volts where as most of the controllers he has looked at are around 0.4 Volts
I wrote @Qiotek about the issue to see if they had any insight on this. He confirmed that this is a known issue with the Zealot series flight controllers. This is due to a TXS0108 level shifting chip on these flight controllers. He said that UART 5 is not connected to this chip and the OSD will work on that UART. I confirmed that it works on both my Zealot H743 and F427. So it appears that this is a flight controller issue and not a VTX issue.
Big thanks to @andyp1per and @yaapu for helping through this troubleshooting.
I’m sorry for missing your discussion while I’m on a business trip abroad.
This fault on walksnail VTX not only occurs on our FC, also on other FCs if serial ports with shifting chip. @andyp1per @yaapu @bnsgeyer
Hello,
I am looking into ways to implement a MSP OSD for OpenHD.
From a development perspective, it would be helpfull to have a tool that streams msp dp data to a udp localhost port (basically a playback of a recording in raw format).
Anybody here who knows such a tool / has done something similar ?
Hi, I don’t know why Google and the forum search engine didn’t show this thread to me earlier. It sounds like I have the same issue on my wing fc-10:
I will check if my uart levels are also off. Isn’t it possible to use a pull-down then? Or is the level shifter too powerful?
My serialport voltage (TX pin
rx-tx.zip (17.7 KB)
of the FC) is also between 1.0 and 3.35 V. So I guess I am having the same issue. I attached the communication on rx and tx when the video transmitter is connected.
Is there a simple solution for this…?
I attached a 680 Ohms pull down to the tx pin of the fc. This seems to work, I have an OSD! It results in a voltage between 0.6V and 1.6 V on the FC TX pin…