Hello,
Through different questions already asked on your website, we have been able to solve majority of our issues.
However, for the custom we are currently developing, we cannot have the USB3.0 interface working.
We would like to solve this issue in the next iteration of our custom board by understanding what is preventing us from using the USB3.0 interface on this very design.
To avoid you some extra questions, I have resumed most of the things we developed, tested and probed.
- Schematics / layout
The board is using the example/guidelines given by cypress AN70707
The board is using the reference given by eCon Systems for their CX3 + OV5640 Dev board schematics.
SSTX+ and SSTX- have both a 0.1uF 10% 6.3V capacitor placed close to the CX3.
The connector used is a B8B-PHDSS(LF)(SN) with a custom cable using USB3.0 Type A on the other end.
This cable is expected to work fine as it is used on another device.
If necessary I can share the schematics/layouts related to the USB3.0 lanes.
- Firmware
We did not apply any modification in the firmware regarding the USB3.0 interface and the clocks used. Ou custom board is working fine on USB2.0. Is there attention that should be given to something before expecting the CX3 to enumerate as USB3.0 ? At this stage, we are only looking to enumerate as 3.0, even with an example firmware and this is not working.
- U3TX and U3RX powers
We have originally measured a noise above 30 mV on these lanes and as such we have disconnected these lines from the onboard voltage regulator and supply them with a external stabilised power source which was giving 20 mV of noise. This didn't solve our problem and CX3 was still recognise as USB2.0 only.
- SSTX and SSRX wires
I have probed the SSTX and SSRX lanes before, during and after the firmware flash and can't see any real activity. The images attached are the results obtained in all of the case above. My oscilloscope is only rater for 110MHz, it might be complicated to probe these lanes correctly.
- Wireshark
As I have seen in similar topics that Wiresharks data were important. I have attached to this message the Wireshark file recording from device being plugged in to firmware flashed and video correctly streaming.
As a potential important point, the onboard clock is 19.2MHz and not 24MHz.
I'm absolutely available if you need any more info or if you want me to test something else.
Thanks i
My colleague @cam will also follow this topic and answer your potential questions.
