ExpressLRS / CRSF laggy

Thank you very much ! It worked ! Hope this can help others with the same problem.

So can you confirm you see the difference comparing your original connection and TX1/RX1 ?

@andyp1per could you please advice how to detect the DMA-capable port by hwdef file?
For example for BeastF7 board ardupilot/hwdef.dat at master Ā· ArduPilot/ardupilot Ā· GitHub

The easiest way is to use mavproxy. Here it is on a MatekH743:

STABILIZE> ftp get @SYS/uarts.txt -
STABILIZE> Getting @SYS/uarts.txt as -
UARTV1
SERIAL0 OTG1  TX =   18435 RX =     738 TXBD=  7638 RXBD=   305
SERIAL1 UART7 TX =       0 RX =       0 TXBD=     0 RXBD=     0
SERIAL2 UART1 TX =       0 RX*=       0 TXBD=     0 RXBD=     0
SERIAL3 UART2 TX*=    1095 RX*=       0 TXBD=   453 RXBD=     0
SERIAL4 UART3 TX =       0 RX =       0 TXBD=     0 RXBD=     0
SERIAL5 UART8 TX =       0 RX*=       0 TXBD=     0 RXBD=     0
SERIAL6 UART4 TX*=       0 RX*=       0 TXBD=     0 RXBD=     0
SERIAL7 UART6 TX =      15 RX =       0 TXBD=     6 RXBD=     0
SERIAL8 OTG2  TX =       0 RX =       0 TXBD=     0 RXBD=     0

The * means DMA-enabled

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Yes absolutely, now it works well.
I have also read another suggestion that is to keep rx6 and tx 6 and change BRD_ALT_CONFIG to ā€œ1ā€ as written here Mateksys F765-WSE ā€” Plane documentation
Anyway andyp1per method worked perfecly.

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alt config does not affect DMA allocation unfortunately

Hello,
I too have been facing a similar issue regarding laggy ELRS. I have a Matek H743-wingv2 paired with an ELRS R9 Slim+OTA that has refused to work properly with Ardupilot. Changing the RX serial port to Serial 3 (DMA-enabled) doesnā€™t seem to have worked. Could I be missing something?
Thank you in advance.

http://www.mateksys.com/?portfolio=h743-wing-v2#tab-id-6

I donā€™t use ELRS, but CRSF so If Iā€™ve got it all together right then you should be on TX/RX6 (Serial 7)

BRD_ALT_CONFIG,1
SERIAL7_PROTOCOL, 23
SERIAL7_OPTIONS,7 or 0 #Depending on the telmetry you're using you might need to play with this.

Post your config, Iā€™ll see if I can replicate. What version of ELRS are you using?

RC_OPTIONS 256
RC_PROTOCOLS 1
SERIAL3_BAUD 57600
SERIAL3_OPTIONS 0
SERIAL3_PROTOCOL 23
ELRS 3.0.1
Arduplane 4.2.3
Any other params you want me to share?

I also get this series of messages on startup:
messages

Thank you

Thank you, Iā€™ll test & post an update.
Edit:
Upon changing SERIAL7_OPTIONS to 7 ELRS was completely unresponsive. When changed back to zero I got the previous laggy signal that I had been experiencing.

Full parameter list please. Just post the file. This is 868Mhz?

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I changed it to .txt as the .parameters file that qgc generated was not authorized for upload.
parameters.txt (31.2 KB)
And yes, I am using 868Mhz.

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Sheesh, three hours of my life that I wonā€™t get back updating to ELRS 3.0.1. Feels very bleeding edge. Anyway I am finally on 3.0.1. Will have a go at reproducing another day.

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What were your roadblocks? I found it pretty easy to upgrade my own hardware. I am a bit of a channel hog, so ELRS 3.x was a necessity before I tried using it more than as a passing interest. I like it so far.

I have had exactly this problem several times.

Serial RX reciever to FC is working, but Serial TX is not.
On one of my matek FC its was an hardware option, Iā€™ll see if I can find the notesā€¦
The normal exchange is not working

I couldnā€™t go straight to 3.0.1 from a reported ā€œ2.0ā€, I had to first flash 2.5.1 and then flash ā€œrepartionerā€ and then flash 3.0.1 and even then it claimed failure, but seems to be working. Needless to say discovering these steps on the net was non-trivial.

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Ok, I have tried setting up your settings on a Durandal and am getting some very weird behaviour that is definitely related to ELRS. My guess is that something in the protocol consumption code is consuming all the CPU because of CRSF invalid packets from ELRS (has happened before). Not going to be a quick fix I am afraid, but I will certainly dig deeper.

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Ok, issue was you having the lost model sound on a switch :smiley:

So I have your setup working, no sign of lag or notchiness. You need to provide a few more details:

Please also use Plane 4.3.1 so that we are talking about the same setup.

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I am terribly sorry for my late reply, I didnā€™t check the forum since nobody mentioned me.

I bought an H743Wlite, Betafpv 2.4g SuperD, and a Betafpv microtx 1w to start another build and to see if that would resolve the issue.
On a completely stock (save for the radio/serial related parameters) Ardupilot 4.3.3 firmware and ELRS 3.2 with the mentioned hardware I still have the stick lag, without the lost model sound switch setting.

What other details do you need?

Thank you so much for your time.