I've implemented a TUSB2046B hub, but can't get it to communicate with downstream devices (mouse, keyboard). I think it emumerates to the root port, as I can see bursts of transaction activity on a scope (I don't have access to a protocol analyser). This happens while my AMD CPU module is booting Linux. When it reaches the login stage, the bursts stop and the TUSB2046B suspend pin goes high.
I can't see any activity on the downstream side. I've got a commercial 4-port hub attached to my port 1 (this hub and attached mouse/keyboard work fine when used on another computer).
I'm using an external 6MHz clock signal that swings from 0 to 3.3V (with a bit of overshoot too) Is that likely to cause any problems?
Without mouse/keyboard it's a little hard to do any investigation from the host side. Any other ideas?
I think it was optimistic to say the hub has enumerated! Further examination shows that it is only getting short messages (about 3uS long) in each frame time. These may be no more than SOF packets, so probably the TUSB2046 is not responding.
I fixed it!
PCB connection problem, nothing more. Interfaces now work fine
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