custom uart usage
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 Hi, 
 I wanted to add a custom sensor to my voxel-2 through j19 UART.
 now I see that this UART is reserved to RC-inputs. but even when I disabled those in /etc/modalai/voxl-px4.conf, I still can't access the port.
 I looked a bit and found this:
 https://gitlab.com/voxl-public/voxl-sdk/core-libs/libqrb5165-io/-/tree/master/python?ref_type=heads
 and tried using it with port 7.
 when I tried to write it gave me the following:
 ERROR: voxl_uart_write: Bus '17' is not initialized
 and on init, it gave:
 Sending library name request: libslpi_qrb5165_io.so
 Sending initialization request
 Received standard error event SNS_STD_ERROR_NOT_SUPPORTED
 Couldn't configure flight_controller sensor
 ERROR: fc_sensor_initialize failed
 ERROR: Failed to initialize slpi
 ERROR: Encountered error while initializing bus 17so it looks like it is still looking for some RC sensor. 
 I guess my real question is how can I access SLPI UART as a user since I don't see them in /dev/tty*
 Thank you
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 @giladWDS To specify. my sensor is connected to a microcontroller. so also I prefer UART I can do i2c(I have tried and it didn't work as well) and I can do SPI if it works better. 
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 @giladWDS The I/O on J19 is only for use with the DSP, not the Linux processor. If you are running PX4 then you would need to write a custom PX4 driver for your sensor. The libqrb5165-io library would allow access to the UART but only if PX4 is not already running on the DSP. It's either PX4 or libqrb5165-io, you cannot use both at the same time. You can get an applications processor (Linux processor) UART via some of our add-on boards but there isn't one available directly from any of the I/O connectors on VOXL 2. 
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 @Eric-Katzfey 
 Thank you for the reply
 The only board I have no for testing is:
 MCCA-M0151-1
 I use the USB portion for the wifi and see that it exposes a uart port- HS1 for the external USB board.
 I can't seem to communicate with this HS0 port as a standalone port.
 Is it only for external Flight controllers?I looked into this: 
 https://docs.modalai.com/usb2-type-a-breakout-add-on/
 but it seems to expose the same uart I can not talk to.
 Can you please recommend me a board that won't affect the wifi capability but would add uart ports that I desperately need?- EDIT:
 also if push comes to shove I would appreciate sources on how to write and compile a px4 driver that reads from the uart on j19.
 Thank you and best regards, 
 Gilad
- EDIT:
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 @giladWDS M0151 should expose /dev/ttyHS1 for use. It's just a UART so it isn't specific to external flight controllers. 
