VOXL2-Mini J19 devices

voxluser12341

Hi, I'm interfacing with the qrb5165-io library to access the UART/I2C connectors for external sensors. I know that the UART ones such as QUP2, QUP6, and QUP7 can just be accessed by passing in their respective enum into voxl_uart_init(), but I was wondering which devices they are mapped to in dev/, i.e. the J10 port is mapped to dev/ttyHS0. Thanks for the help.

Alex Kushleyev

@voxluser12341 ,

Please note that currently qrb5165-io library only allows access to a single uart device, you cannot run it concurrently on multiple devices. Additionally, you cannot run qrb5165-io concurrently with PX4 (PX4 can access the uart ports concurrently)

The uart device numbers correspond to the QUP_SSCx number (where x is the uart bus number), you can review the pin definitions with pin names here : https://docs.modalai.com/voxl2-mini-connectors/#j19---external-sensors-2x-uart-2x-i2c. so, for example, J19 pins 7 and 8 are UART2 TX and RX.

The UART, I2C, SPI ports that are connected to the DSP (aka SSC, aka SLPI) are not exposed on the file system in /dev/

Alex

voxluser12341

@Alex-Kushleyev

Thanks for getting back to me. So when you say that "Please note that currently qrb5165-io library only allows access to a single uart device, you cannot run it concurrently on multiple devices", it means that I can't be reading/writing from let's say /dev/ttyHS0 and QUP6 at the same time? Or the ports connected to the DSP, i.e. I can't do QUP6 and QUP7 at the same time? My current work involves building a program/service that runs on the VOXL-2 mini at startup. It will use the qrb5165-io library to read/write serial data to/from connections at each serial port and set up a running TCP socket for each of them that I can read/write serial data on those ports from other devices that will connect to that socket over ethernet. Are you saying that this is not possible?

Alex Kushleyev

@voxluser12341 , the qrb5165-io limitation only concerns the UARTs that are connected to the DSP, so SSC_QUP2, SSC_QUP6, SSC_QUP7 (dsp uarts 2,6,7).

The limitation does not apply to any Application Processor (APPS_QUP) ports which show up as /dev/ttyHSx

qrb5165-io library could be extended to support multiple concurrent ports, but we have not done that yet, unfortunately.

Alex

Gary Holmgren

@Alex-Kushleyev I am wondering how I could map QUP2 VOXL2 J18, VOXL2 to work with the voxl-microdds-agent .service script that normally starts up in UDP.

ExecStart=/usr/bin/MicroXRCEAgent udp4 -p 8888

I want to change it to read from the J18 port on VOXL2 which has access via the Apps Proc as I am connected to it with an external FC (the FCv2). I know it would work on the /ttyHS1 with my UART expansion board but that is dedicated to a different motor controller board so i cant use that one unfortunately. Since I have voxl-px4 disabled there should be something I can put in this service script that would allow the microdds agent to read the uORB topics in PX4. Let me know if you have any suggestions.

Eric Katzfey

@Gary-Holmgren I'm thinking you could write a program that uses libqrb5165-io to communicate via the UART on J18 and then expose the traffic on UDP on the applications processor. Sort of like a bridge application.