Part Number: AM5728
Hi all. This could be user error, meaning I just need to write to a couple of registers, or it could be something wrong with my design. I'll paste a screenshot of the schematic below.
Basics: I connected USB2 to a TUSB4041, which drives three USB mini-B jacks. Non-standard, I know, but the system has space constraints. It basically works - we can connect thumb drives to the jacks, transfer data, etc. I want to do some testing to check the eye diagram, jitter, etc. At the test facility, we couldn't get the test patterns to appear at the jacks. I can get the 5728 USB port into test mode using the debugger as directed here: http://processors.wiki.ti.com/index.php/Linux_Core_DWC3_User's_Guide#USB_2.0_Test_Modes. When queried, the processor then reports it's in the mode commanded. However, we don't see the test patterns at any of the jacks. Do we need to do something to tell the processor to route the test pattern to a particular 4041 output?
If I recall correctly, the 5728 did not detect that the test fixture was plugged into a jack. I feel like that's part of the problem, but I don't know why we can detect a thumb drive but not detect the tester. Thoughts?
This might need to be referred to USB experts.
In reply to Elias Villegas M.:
In reply to Michael Doyle:
The pdf describing the test method clicked for me. I've emailed the test house I'm using to see if they were using the PID VID method (I'm thinking some specialty scopes should have this built in by now, or built into the scopes' accessories). If they were, then I need to know why enumeration failed. If they weren't, then maybe we can try that.
Would the TUSB4041 be responding with test patterns, or would the host be doing the responding?
I'll return to this thread when I get some answers from the test house.
There are two ways to get test packets from the downstream ports of the hub:
Force the hub to pass through a test packet generated by the host using a USB Test_Force_Enable command. Please be aware that this test packet may not pass USB HS SQ eye diagram testing. The signal quality mask is expecting a test packet that is being generated by the port the test hardware is attached to, not a repeated test packet.
Force the hub to generate a test packet on a downstream port using USB Test_Packet command for that specific port.
In reply to JMMN:
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