xu208 is very difficult to connect to android phone

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Paul Wang
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xu208 is very difficult to connect to android phone

Post by Paul Wang »

Dear Men:
I have completed testing my usb audio application on PC. Based on important application on android phone,I find it very difficult to be observed by android phone via type c connector.
Repeatedly plugged the usb jack for hundreds,there is only several times my board can be observed.Anyone can give some guide ?
Here is the schematic of type c connector of my board.
connector.png
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connector.png
(44.64 KiB) Not downloaded yet


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mon2
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Post by mon2 »

Hi.

1) What are the details of your USB cable? The XMOS IP is HS (high speed @ 480Mbps). For this reason, the quality of the cable does matter. Test again but with the shortest cable you can source. If possible, search for a cable that is USB-IF TID certified. Such a cable has gone through exhaustive eye pattern tests so that the signal quality is good from one side of the cable to the other. Although it sounds crazy due to the flood of manufacturers of USB cables, the quality does matter.

In your design - you are applying a passive USB Type C to USB Type C for USB 2.0 use? That is, the cable is not with an E-marker which embeds a controller for power delivery (> 3A)?

2) You can check the sleeve of the USB cable to confirm if the raw cable used in the assembly is USB compliant. We demand this for our cable assemblies and have had zero issues with our USB designs that are paired with such cables. In Asia, there are many quality suppliers but absolutely test with a short USB cable (6" sounds good) and report your results.

3) USB is an impedance controlled design - was this care taken in the PCB layout? Did your PCB shop perform impedance control for the USB traces @ 90 ohms? Please check the many appnotes on USB layout details on the internet from TI, Diodes Inc, Microchip, etc. After your PCB files are submitted, the PCB shop will perform a TDR check on these traces. This may be an issue on your product. Speaking from experience, Suntak (Shenzhen), Kingford PCB (Shenzhen), China Fast Print (Shenzhen), Founder (Shenzhen) can all do this level of testing at fair or zero costs.

4) So all tested PCs work fine?

Start with the above reviews and report back.
Paul Wang
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Post by Paul Wang »

report :
1): I use three piece of type c compliant cable with no E-marker. One is with complete type c wires,others with only D+/D- CC pin. I have tested them with other type c device.
There is a higher probability being observed when I force RST_N down.Maybe signal quality or timing is Unreliable(The timing from VBUS to RST_N is 5ms I have measured).
3):I have not made impedance controlled design. You are right,I will do this for next version.
4):In the current ,it works fine on PC.
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mon2
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Post by mon2 »

Power rail sequencing and timing is also very important. Please post your power supply and reset supervisor circuit for a review. You can also check the assorted kit schematics from XMOS for guidance.
Paul Wang
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Post by Paul Wang »

Power rail and supervisor circuit works fine on PC. Let me try to find the difference getting on contacted with OTG connector of android phone first.
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mon2
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Post by mon2 »

Consider to run the XMOS mouse IP which operates in high speed mode (480mbps). Does AN00129 run for hours without any issues on your PC? Try it and attempt plug / unplug actions on your custom design.
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mon2
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Post by mon2 »

Hi. In reviewing another case- found a very good article that is attached.

Would you please test with the 1k5 resistor (pull-up to +3v3) on USB_D+ line as noted in this document?

Please post your update after testing.


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mon2
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Post by mon2 »

Hi. Were you able to get this working with the android phone?

Do run the TDD.EXE from TheSycon which is a USB descriptor validation tool that also raised assorted errors with the XMOS IP. How does your IP score against this test tool ?
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