Re: Rare errors in data transmission with FT2232H

[Vojtech Michalek <vojtechuv@xxxxxxxxx>]

In order to try to get additional information on the errors origin, I decided to replace libftdi programs with an alternative ones using proprietary ftd2xx library. I did not expect any significant change, but it has transferred more than 4GB without any error so far.

Vojta

On Thu, Apr 4, 2013 at 5:26 PM, Vojtech Michalek <vojtechuv@xxxxxxxxx> wrote:

Hi all,

during my measurements, I encounter rare errors in data stream (i.e., approx 10 errors in 1GB data). I use FT2232H in standard asynchronous serial mode at 3MBd, transmitting approx. 300kBps. I try to debug it while sending incrementing 16bit number in a loop, so that I could check what happens with data. From time to time a data block of various size is missing.

The same behaviour is reproducible with two topologies:

1) transmitter: LPC1343 microcontroller, receiver: FT2232H

2) transmitter: FT2232H, receiver: another FT2232H

In order to exclude I do something wrong with libftdi, I try to read the data from FT2232 with linux command "cat" (and write with system command write for the second topology). I got similar error rate as with libftdi functions but with an additional strange effect. Two zero bytes are stuffed in the data stream with the following "structure": single zero byte, after next correct 511 bytes comes second zero byte, and after next correct 3587 bytes (really strange number to me) is the missing block of data. Then several hundreds of MB of correct data follows before next error occurs.

Have you any hint what I could try to make the communication more reliable?

Thanks,

Vojta

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