ESP32 Forum

Hi,

I've been reading the schematics for the ESP32-S2 devkit that has the mini-1 on board and was wondering the following:
a) Why does it have USB to UART bridge (CP2102N). Shouldn't the D+/- signals be able to connect right in to the ESP32-S2 chip to provide firmware uploads and even remote serial?

b) The board uses a 5 -> 3.3V voltage converter and the SK68XXMINI-HS LED is connected to the 3.3V line. But the LED is rated for 3.5V - 5.5V. Wouldn't been better to power the LED from the 5V line instead + use logic level converter for the pwm signal? Or does it perform okay with 3.3V?

c) The ESP32-S2-Mini-1 data sheet says that "IO18 on the module should be pulled up to VDD33 through a 10 kΩ resistor". The devkit does have the pullup, but it's marked as NC (Not Connected). Why?

--john

I will skip over for the opinions about a and b. For c, the IO18 on ESP32-S2 boards is connected to the on board WS2812B LED. The same pin can be used to drive simultaneously an external chain of RGB LEDs. The I2S mechanism supported by DMA is an easy way to drive those LEDS.

a) it is devkit board, which means it is intended for developing; for that you need to have access to logs from UART and at the same time access to USB peripheral (assuming you want to work with USB); of cource it is possible to use USB for logging purpose, but it would not let you to use peripheral in your device
b) maybe its matter of price or maybe of accessibility, currently you may find problems to buy big amounts of ws2812 from some suppliers, important is it is working, even if not as bright as it should be

As for B, the LED is there to demonstrate how you can use addressable LEDs, not so you can use it as an emergency flashlight. Powering it at 5v is a waste of circuitry for no practical benefit whatsoever.