[Ftdi-usb-sio-devel] F232R missing/added bytes

[Eike S. <ei...@al...>]

Hello all,

I'm encountering both randomly missing and added (repeated?) bytes while
using an FT232R in loop-back mode with RTS/CTS handshaking enabled,
lange packets make the problem worse, higher bit rates as well. I'm
currently using a 2.6.31 kernel. My final goal is attaching an
FPGA-based design with proper handshaking and buffering at 3M Baud/s,
the problem surfaced while developing the FPGA design and encountering
corrupt data, I went back to the loop-back connection for debugging.

Luckily, I was able to compare a serial port dongle employing an FT232B
and could find no such problem at up to 500k Baud/s. My wild guess is
that the problem might be related to the smaller buffer size of the
FT232R.

However, I'm neither familiar with kernel driver nor USB programming,
and so I'm stuck right now. How do I go about debugging this kind of
issue?

Best regards,
eike