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Discussion - Hardware / FT602: How does individual WR_N transactions becomes 1 bulk packet?
« on: September 29, 2020, 05:18:25 AM »
Hi,
I have successfully ported pattern generator example to my custom PCBA and I can see vertical colour bars on PC. I am studying the how the UVC header and data is being sent from FPGA using WR_N transactions. I also used Wireshark to capture USB tranffic and observe that multiple WR_N transactions are consolidated into 1 USB bulk transfer of size 12 bytes (header) + 640x480x2 bytes (yuy2 data).
I am confused by how FT602 knows which of the WR_N transaction is the start of UVC frame and which is the last? What is the purpose of sending data = 0x00000055 and BE = 0x1 and the end of yuy2 data? This 0x55 byte is not captured by Wireshark even though it is sent by FPGA to FT602.
Regards,
Magip
I have successfully ported pattern generator example to my custom PCBA and I can see vertical colour bars on PC. I am studying the how the UVC header and data is being sent from FPGA using WR_N transactions. I also used Wireshark to capture USB tranffic and observe that multiple WR_N transactions are consolidated into 1 USB bulk transfer of size 12 bytes (header) + 640x480x2 bytes (yuy2 data).
I am confused by how FT602 knows which of the WR_N transaction is the start of UVC frame and which is the last? What is the purpose of sending data = 0x00000055 and BE = 0x1 and the end of yuy2 data? This 0x55 byte is not captured by Wireshark even though it is sent by FPGA to FT602.
Regards,
Magip