Hi Eli, Thanks for your suggestion. I will try that.
JC From: [email protected] [mailto:[email protected]] On Behalf Of E.S. Rosenberg Sent: Sunday, April 12, 2015 10:59 PM To: [email protected] Subject: Re: Two last bytes missed in callback function (stream data) 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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[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]<mailto:[email protected]> ________________________________ libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]<mailto:[email protected]> ________________________________ libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]<mailto:[email protected]> -- 217-351-2655 ext. 126<tel:217-351-2655%20ext.%20126> Distant Focus Corporation 4114B Fieldstone Rd Champaign, IL 61822 http://jupiter.distantfocus.com/projects/ ________________________________ libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]<mailto:[email protected]> ________________________________ libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]<mailto:[email protected]> ________________________________ libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]<mailto:[email protected]> -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
