I created the system that 4k byte data is transferred through EZ-USB bulk transfer. FPGA (target side) create 4k byte data created and host side received data.
But we sometimes found that EZ-USB FX2 packet data is lost 512*N byte data. And packet reading time is sometimes takes 100msec or more. (usual case average is 16-17msec)
EZ-USB FX2 has two 512 byte buffer that is used as FIFO. I guess to have it overwritten unexpectedly.
This same experience that someone for?
And how you resolved?
FPGA: Actel APA-450-BG456
Driver: Windows almost as a sample using the Bulk Transfer
PC OS: WinXP
USB Target: 512byte * 2 FIFO memory used in
□ System Specifications
• USB Bulk Transfer
• Baud rate is about 2Mbps
• FPGA allows every 16msec burn data to create a 4K SRAM save nearly
• FPGA look at the USB Overflow flag Overflow if not designed to write data
• Host-side applications, a simple data earnestly Read
□ worrisome phenomenon
• The data of received at the host is 512*N bytes lost
• Read by the host, but sometimes time-consuming than the 100msec