Hi, I am using latest available firmware, QRB5165.1.0.0-210512, but when I try to write to UART0, there is no data output on the pin. I am observing the electrical signal with an oscilloscope. Is there a known bug/problem with this release?
Thank you,
Ramon V.
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Hi Ramon
You use sdkmanager to update LU build? QRB5165.1.0.0-210512 is for LU release, right?
How do you do your test for UART0?
Thanks
Kevin
Hi Kevin,
Yes, I am using sdkmanager for updating the board's firmware.
The simplest test I always use and never fails is "minicom". I setup as device /dev/ttyHS0, 115200 8N1, No Hardware Flow. I simply connect the TX0 pin to the oscilloscope and press the keyboard. I should be seeing any signal.
Thanks,
Ramon.
Hi Ramon
We will reproduce your test.
Thanks
Kevin
We had similar problems with UART0 only to realize that UART0 (on connector LC1) is mapped to /dev/ttyHS1 (not ttyHS0) and UART1 is mapped to /dev/MSM0 in the LU build we are running. You'll have to set DIP switch #1 position 2 to OFF on both the I/O board and the navigation board (if you have both boards installed) for UART1 to work.
In addition, we had to disable the agetty agent running on ttyMSM0 (systemctl stop [email protected], or systemctl disable [email protected] if you want it to be permanent through a reboot) to get UART1 working properly. If you make it permanent you will not be able to login on the USB debug port if you switch the DIP switch #1 position 2 back to ON
In case you are not aware the LC1 UART signals are at 1.8V. We had to build a small custom interface board since our external devices have 3.3V or 5V UART interfaces.
To continue due to posting issues. If I try to share the simple Linux command to send data over the serial port the forum rejects the post as to not being in English. Oh well.
Having said all that we are still experiencing a strange problem with the /dev/ttyHS1 device. We can lock up the receive side if we do not send data (a write) every few reads. As long as we send a byte every couple reads it works, otherwise after 7-10 reads the receive side locks up until another write is called. By locking up I mean the read returns one byte (usually an 0xFD) with no returned error code. An oscillicope shows the packet of bytes we are sending across on the wire arriving correctly at the LC1 connector, but just not received with the read() call. We are not using hardware flow control. Are there known issues with ttyHS1? Is the Qualcomm kernel serial driver source code available for review to investigate further? I can provide a small test case if that would be useful. Maybe we're not setting some driver parameter correctly.
Bruce