gsoc-2014-hdmi2usb

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Jun 13, 2014 • Ayush (PTZ/Serial Extension)

Tags: news hdmi2usb ptz serial-extension

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- It turns out that Sony PTZ cameras need DTR/DSR flow control and Canon PTZ cameras need RTS/CTS flow control.
- There must be ports on the serial expansion board with hardware flow control enabled.
- So these ports would require additional INT IN endpoint apart from BULK IN/OUT.
- Also each of these would require 6 FPGA pins from VHDCI.
- So there is an open question - how about having just 2 or 4 of these flow-controlled ports? And rest of them without flow control?
- A majority of serial devices work without flow control, and even these PTZ cameras may work without flow control at very low baud rate. But I don't have PTZ cameras to test so I wouldn't want to take chances.
- And there is another question left for us. Do CDC ACM drivers support Bulk only CDC ACM serial port, i.e. the ones without INT IN endpoint?
- Flow control is also a concern with the Numato board design, because that also seems to ignore RTS/CTS and DTR/DSR flow control. Only RX, TX is used in the schematics that I was shown. While this would work with RS422 pretty well, it might not work with RS232C based cameras.
Originally posted on Serial port expansion for HDMI2USB with PTZ camera control example