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USB 2.0 3.0 OTG Serial Gadget LS1021A TWR Board

Question asked by Elias Bitbaker on Jan 13, 2020
Latest reply on Feb 3, 2020 by Yiping Wang



I am trying to configure USB 2.0 (A) or USB3.0(B) as serial port on the eva board of LS1021ATWR. I know USB3.0 (B) has USB2.0 in it, and there is another USB2.0 (A) see Figure 2-9


I said USB2.0 as A here to indicate this is only USB2.0 controller not the USB2.0 in USB3.0


I said USB3.0 as B here to indicate USB3.0 controller which has both USB3.0 and USB2.0


Correct me if I am wrong


From the TWR-LS1021A reference manual. I found



Seems like if I want to use USB1 (USB3.0 which contains USB2.0) to achieve serial access I need to get rid of the HUB on the board? what if I need to use USB2 to achieve serial access.

I assume these two pins are either (D21 and D22)  or (D23 and D24) is USB 2.0 all I need to do is to connect the usb 2.0 cable wires (4 in total) , D+ and D- to these two pins.


Now question comes to what do I need to do to configure the USB 3.0 (B) or USB 2.0 (A) to serial port.



I already enabled necessary modules from the kconfig.


(1)what do I need to modify in the device tree file ?

the one @8600000 is USB1 or USB2 from Figure 2-9? It says host which is not the right mode for serial.


(2) what do I need to do to make USB3.0(B) acting like serial port?

(3) what do I need to do to make USB2.0(A) acting like serial port?

(4) if (2) is available how do I test it ?