Uart stops working

[oli]

Hi all,

i'm using the pyboard for LIN communication, and it is working well so far. But i have some trouble with the uart itself. at some point it stops working! there is no error, the script is working and i get output over the repl, but i get no bytes over the uart. restarting solves the issue. is there a way to find out, where the problem could be?

thank you!
Oli

[oli]

since no one had an answer and in my application i had a lot of problems with stopping uart, i found the cause (hopefully). the USARTx_SR register did indicate an ORE flag, and then the .any() returned "false". so the application stopped. now, i check the SR register and if the ORE bit is set, i read, according to the manual of the stm32f405, first the SR and then the DR register. this seems to solve my problems...

[dhylands]

Interesting. It seems that the default is to use a 64-byte buffer, which means that an interrupt handler is installed to transfer data from the HW to the buffer, so I wouldn't have expected ORE errors to be occurring.

Obviously, the driver needs to be improved a bit since it should self recover from that rather than "lockup".

[oli]

hi,

i have the read_buffer_len set to "0", because i hve to receive the LIN-break and so the recv-flags must match the current received byte.

[dhylands]

ok - I would expect overrun errors when using a read buffer of zero.

Perhaps we need to widen the existing fifo to include the character statuses (like break, parity error, etc)

[oli]

that would definitly solve the problem. perhaps i can take a look into it...

[JimTal001]

I am now using the USB serial converter suggested by blmorris
http://www.adafruit.com/products/954

I have it connected to X1,X2 and Gnd. I am happy to say it is now generally working (after many driver install issues).
However, the shell.py program written by Dave (dhylands) will not work. When I type import shell to the terminal it kills REPL (no more communication). Dave's program is very helpful in viewing log files stored on the SD. If anyone has suggestions I would appreciate the assistance.

[dhylands]

I seem to recall having some issues with shell.py when using the HW UART.

You might want to try changing the repl = pyb.USB_VCP() line: https://github.com/dhylands/upy-shell/b ... ell.py#L35 to point to your uart instead. If that doesn't work, you can always uncomment the second implementation of term_size https://github.com/dhylands/upy-shell/b ... py#L48-L49 that hard codes a terminal size. The terminal height isn't used anywhere, and the only place that uses the terminal width is the ls command.

The code is sending a special escape sequence to your terminal and reading back the result. However this is problematic when the repl is being sent to 2 places (because then both places could reply), so I wound up having to hard code it to read from the USB REPL. Te way its coded right now, when you use the UART as a REPL it hangs waiting on the USB to reply .

The pyb.repl_source function that I proposed wasn't accepted, and I have on my todo list adding something called a "pluggable" REPL so that you can install your own REPL behaviour, but that hasn't happened yet.

[JimTal001]

What did work was enabling the commented out terminal size function.
Thanks Dave.