Have you tried what the kernel-driver 'sees'? (ie. /dev/ttyUSBX instead of libftdi)
HTH, Eli 2015-04-11 3:23 GMT+03:00 Julio Cruz Barroso <[email protected]>: > Ryan, > > The answers at the same order: > > - No show up at the start of the next transfer. They are missing > completely when the package size is 512 (including the status) > - All the package have the status bytes: 0x32 0x60. > - linFTDI filter the status bytes correctly. > > Thanks > > Julio > > On Apr 10, 2015, at 11:05 PM, Ryan Tennill <[email protected]> > wrote: > > Do the missing bytes show up at the start of the next transfer or are > they completely missing? There are status bytes sent by some/most/all? the > chips that would eat into the available payload space. I don't remember if > libFTDI filters these bytes out or not. > > ref: > http://www.ftdichip.com/Support/Knowledgebase/index.html?an232b_04smalldataend.htm > ref: https://code.google.com/p/usb-serial-for-android/issues/detail?id=4 > > Ryan > > On 04/10/2015 06:26 AM, Julio Cruz Barroso wrote: > > Hi All, > > > > I try to run the same testing in Windows using FTDI libraries in D2XX > mode. > > > > The results are similar in synchronous mode, every 510 bytes, data is > missing. > > > > - At 4B/s there is no data missing. > > - At 4000B/s start missing 2 bytes every 510 bytes > > - At 5MB/s is missing 2 bytes every 510 bytes > > > > The attached file show the FT2232H signals during every transmission (at > 4B/s, 4000B/s and 5MB/s) and the source code including the initialization > and read loop. > > > > It seems that was not a problem in PC (libusb, libftdi, d2xx). > > > > Has anyone had the same experience? > > > > Regards > > > > Julio > > > > > > *From:* Julio Cruz Barroso > *Sent:* Friday, April 10, 2015 9:38 AM > *To:* [email protected] > *Subject:* RE: Two last bytes missed in callback function (stream data) > > > > Hi all, > > > > In my previous email, I switched (my mistake in the text) synchronous and > asynchronous mode!. In fact, the system is working in asynchronous mode > (10MB/s) and is missing two bytes in synchronous mode. > > > > Julio > > > > *From:* Julio Cruz Barroso > *Sent:* Thursday, April 09, 2015 10:21 PM > *To:* [email protected] > *Subject:* Two last bytes missed in callback function (stream data) > > > > Dears, > > > > Currently, I have a system running a FTDI in synchronous mode. It contain > a FPGA sending data to the PC using a FT2232H (please, refer to diagram > below). > > > > Basically, the speed is controlled by a signal generator connected to an > input of the FPGA. In this case, the throughput could be change easily for > testing purposes. > > > > The maximum transmission speed is around 10MB/s in this synchronous mode. > However, in asynchronous mode there is data missing as explain below using > three (3) different speeds (please, refer to next 3 figures): > > > > 1. The figure 1 shows the data received in the callback function. > In this case, the size is 4 bytes. No data is missing. > > 2. The figure 2 shows a higher speed. In this case, the data size > in the callback function is 40 bytes. No data is missing. > > 3. The figure 3 shows another speed with a buffer size of 510 byte. > After this speed, all the size buffer are the same (510 bytes) and there is > always two bytes missing (in the end of the buffer). > > > > I tried changing the number of transfers and size without success. > > > > Any suggestions? > > > > Thanks > > > > Julio > > > > > > > > > > > ------------------------------ > > *libftdi* - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > > > > ------------------------------ > > *libftdi* - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > > > ------------------------------ > > *libftdi* - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > > -- > 217-351-2655 ext. 126 > Distant Focus Corporation > 4114B Fieldstone Rd > Champaign, IL 61822http://jupiter.distantfocus.com/projects/ > > > ------------------------------ > > *libftdi* - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > > ------------------------------ > > *libftdi* - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > > -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
