The image below shows a Micro USB connector in a smartphone. I understand what the first 5 pins of the USB are i.e. USB_DM, USB_DP, USB_ID , VBUS and GND.
The pin S1 is connected to VBAT (battery voltage pin) through a load switch.
Can anyone explain to me the function of the S1 pin?
Best Answer
S1 is the "USB cable connected" status pin. It wakes up the CPU so a PC is able to detect the phone or so it can display the "charging" status with the USb wall wart.