Hi,
I am using a Raspberry 3B+ and a 2 Channel CAN BUS FD Shield with MCP2518FD and RTC.
I am using configuration dtoverlay = seeed-can-fd-hat-v2.
I have noticed dropping frames when logging data.
Maybe input buffer is full?
Any help?
Thank you
Hi Baozhu,
I attach a picture comparing a log file saved with Canoe in a Laptop using a CanCase (left side) and a log file saved with the Raspberry, can-hat and simple python program (right side).
I have marked the last equal message in both sides. Note the timestamp in the right part, there is a gap of a few milliseconds. So I am losing quite a few messages here.
After that gap, both logs are again equal until a new gap.
I am trying to log all messages in the bus.
As you can see, message sending is quite fast. This is a 500kbit bus.
Also I have tried logging directly avoiding python with the same results. I used:
$ candump -l can0,0:0,#FFFFFFFF
Any ideas? Thank you.
And some info from the board where Drops and FIFO overflow appears:
Hi,
After a few more tests I am noticing that it may be related to number of channels used, Busload and logging duration. All this is pointing to Rx buffer.
My application is basically a dataloger. I keep log of every single message received in the Channel.
1 application for 1 channel and another app. to log 2 channels simultaneously. (written in Python)
The first app. with just one channel works quite good. It looks like Python is fast enough to log all messages to a file.
However, when I use 2 channels (with busload aroung 40%), after 30 minutes aprox., I have problems with FIFO overflow.
If Busload is higher (45-50%) the logging time without FIFO problems is reduced to 15-20 minutes logging.
It looks like Python is not fast enough to clear Rx Buffer and it overflows.
Have you noticed these problems? Any help to solve this issue? Thank you.