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: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
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
libftdi+unsubscribe@xxxxxxxxxxxxxxxxxxxxxxx
