Where can I find examples of using UART module in UIFlow?
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 @zhoubinx said in Where can I find examples of using UART module in UIFlow?:  It looks like the bad thing is from AXP2101 power chip, all the PORTs were set to 5V? Please, any idea of how to lower voltage to 3.3V. It looks like the bad thing is from AXP2101 power chip, all the PORTs were set to 5V? Please, any idea of how to lower voltage to 3.3V.
 I will also find a multimeter to give a test.on your graphic USB-C is not PORT C (blue) - unfortunately it is drawn in blue - but this is USB port which you are connecting your Laptop /pc to M5Stack in general on Ports A/B/C wires blk/red are power pins with gnd/5v on them where other two pins wht/yellow are data/sensor pins with 3.3v expected 
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 Thanks all friends! I finally figure it out. 
 I think it is still related to AXP2101. When I keep the USB-C connected and use PORT C to communicate, it works. When plug off the USB-C, PORT C UART port just never send and receive data. I think it is because the USB-C supply power to the PORT C, not the inside battery. I will try to figure out how to let the battery to give power to PORT C.
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 Hello @zhoubinx I am glad to hear you got it working (at least with USB-C power). BTW: My M5CoreS3 (running UIFlow2 firmware) provides power to all Groove ports (A/B/C) in both cases: running from USB-C or battery. In your hardware setup, what do you need the 5 V of the Groove port for? If you have a multimeter it should be relatively easy to verify 5 V being present or not. Thanks 
 Felix
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 Hi guys I've created an UIFlow2 example (M5CoreS3_Ext_Usb_Power_UIFlow2.0.1) showcasing switching ext. power output (Groove port) and USB power output. You can find it in the UIFlow2 Play Zone. Thanks 
 Felix
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 Thanks Felix! I will study your new example. 

