@romaniuk wrote:
Hi, I use BPI-M2-zero with Armbian (latest from download section, archive folder). There is my CLI tool that uses libmodbus over UART3 (RTU mode) for communication with some modbus device. I enabled debug mode in libmodbus and I often observe errornous reception of 5 zeros on that uart instead of correct message:
Opening /dev/ttyS3 at 115200 bauds (N, 8, 1) [01][11][C0][2C] Sending request using RTS signal Waiting for a confirmation... <00><00><00><00><00> ERROR CRC received 0x0 != CRC calculated 0x71C0I checked the input on UART3_Rx with logic analyser and the contents is correct. In the digital signal domain there is no differences in codes or timings comparing to the correct reception.
I also performed the same test on Raspberry-Pi Zero W and there is no such problems.
I browsed libmodbus source code and there is nothing special, just writing to file, here /dev/ttyS3 device, so probably the problem comes from kernel module that is responsible for serial devices.
Before I dig into kernel I would like to ask:
- does anyone experience similar issues?
- are there any reports of hardware issues with UARTs in Allwinner H2+ that is a base of Banana Pi M2 zero?
Kind regards,
Piotr Romaniuk
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