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No UART Output on VESC6 MKIV

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uwala
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No UART Output on VESC6 MKIV

Hi Everyone,

I'm desperately trying to make the UART output and input work on my VESC6. I currently have a VESC6 MKIV with FW (firmware) 5.1. I have tried all the configurations I can on the vesctool to try and get a UART signal output but nothing seems to work. I am monitoring the TX pin with an oscilloscope to see if any signal appears, but unfortunately the pin stays high all the time.

Can anyone help me with this issue?

Thank you!

TheFallen
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Joined: 2017-09-11 11:46
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If it stays high all the time then maybe it's the serial input to the VESC, rather than the serial output like you think it is.

cbecker333
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I'm having the same or a similar problem on my Unity with VESC FW 5.1
Both Tx and Rx on the Unity's COMM port are reading 3.3v (high) all the time against ground

When I power on the unity: my ardunio thats listening on the UART port receives a few bits of what appears to be garbage. Then it's silence, even after I send a command from my Arduino, like for example `COM_GET_DECODED_PPM` here https://github.com/vedderb/bldc/blob/master/datatypes.h#L712

C Becker

ajpalm
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Hello,

Did this ever get solved because I have the same problem (FW: 5.2, HW: VESC 6 Mk 5)?

No difficulty interfacing with the VESC via USB but no luck with the UART. My oscilloscope shows both COMM port Tx and Rx lines steady high (3.3v and 3.0v respectively). There's occasional signal interference when the motor (6364 160Kv) is running but nothing that could be data.

Thank you,

Andy.

TechAUmNu
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Have you got the app mode set to UART?

ajpalm
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Hi TechAUmNu,

Yes, the 'APP to Use' (under App Settings -> General) is set to UART.

I've just received a VESC Wand and NRF Dongle. After updating the NRF dongle firmware I plugged it into the COMM port and it works. Both with the Wand and with the Android app. Unsurprisingly my scope then shows activity on COMM Tx and Rx lines. If I remove the NRF Dongle the UART TX activity from the VESC continues. However, if I power cycle the VESC without NRF dongle attached then I don't see any COMM activity.

Presumably I need to initiate communication by sending a packet to the VESC, the NRF dongle seems to send 8 bytes or so once a second, once the VESC receives them it starts sending data. I'll read some of Benjamin's robotics posts I’m sure the answer will be contained there somewhere.

Thank you,
Andy.

TechAUmNu
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You can probably have a look at the wand code, might be able to see what its sending https://github.com/vedderb/vesc_wand

SheffyP
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Hi, Im trying to do the same (FW5.2, vesc 6), get UART output for a LCD display. But I cant get the Vesc to output anything.

Any ideas?

tsm
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Sorry for bumping this post but did you happen to find what was wrong with the uart port?
I'm having the exact same problem: both TX and RX are set to 3.3v, the APP I'm using is UART but I can't get "Vesc Tool" to connect to the board. With USB I can get it working.

 

Alternatively I've tried rewriting the app_uartcomm.c to continuously write a simple string to the serial port: I can can see the data coming in but it's just garbage. I've double checked the baud rate and connections.

 

EDIT: I have board with hardware revision HW_410 and firmware v5.2 as reported by Vesc Tool

 

Thank you.