...

1. Select submenus for USB 2.0 controller : Device Drivers > USB support > USB support > USB Gadget Support > USB Peripheral Controller. Select <*> for “Sunplus USB 2.0 Device Controller“.

...

2. Select submenus for USB 3.0 controller : Device Drivers > USB support > USB support >. Select <*> for “DesignWare USB3 DRD Core Support“ and select “Gadget Only mode“ for “DWC3 Mode Selection“. Note that for USB gadget precomposed configurations, there is only 1 UDC configured as a gadget. Here selecting “Gadget Only mode“ for “DWC3 Mode Selection“ will configure USB3 as the serial gadget and selecting “Dual Role mode“ for “DWC3 Mode Selection“ will configure USB2 as the serial gadget due to the USB2 and USB3 device drivers probed sequence.

...

3. Select submenus for USB Gadget procomposed configurations : Device Drivers > USB support > USB support > USB Gadget Support > USB Gadget precomposed configurations. Select <*> for “Serial Gadget (with CDC ACM and CDC OBEX support)“.

...

4. Select submenus for USB Gadget Support : Device Drivers > USB support > USB support . Select <*> for “Serial gadget console support“.

...

6. Execute the make command to build the Linux image.

...

Serial Gadget Console Implementation

Take USB2.0 serial gadget for example.

1. Update the image and boot the system, the kernel messages will stop when “printk: console [ttyGS0] enabled“ and “printk: bootconsole [sunplus_uart0] disabled“. Here sunplus_uart0 is COM4is COM9, and it is the default terminal of the SP7350 platform.

...

2. Connect the SP7350 platform to a Windows PC with an USB OTG cable, “USB Serial Device (COM8COM10)“ will show up in “Ports (COM & LPT)” of Device Manager.

...

3. Open Putty Tera Term in COM8 COM10 and it can send text output to the user and receive text input from the user.

...