The yellow LED on the ESP32-C6 - What is it for? CPU usage?

Qwiic System
1

Howdy,

I have a bunch of ESP32-C6 boards (for my Somfy Glydea electric motors to control my curtains), the SparkFun Qwiic Pocket Development Board - ESP32-C6. Brilliant board so far.

However, the yellow LED. I think it is supposed to be for charging the battery - however I do not use the charging function at all. But my web server in one of my two different (se below) solutions, well it frequently flashes the yellow LED. And it is clearly depending on the load of what the ESP32 is doing. I think at least that is what it is showing, since it flashes when I send something to the web server from my Firefox browser (PC, win10).

BUT my challenge currently is to understand why it flashes more and more with the solution that supports OTA firmwar update.The one without just flashes the yellow LED when the board seems to do something - and that is why I think it shows the CPU load at say above 1.4w or so… Funny it is anyway…

Solution I have is a web server that controls three GPIO output’s for external LED diods - and the web server has three buttons: close/open/myposition. Each button is turning off all GPIO’s, then flashes (200 msec) one of the GPIO ports. No more. And yes there is a status page, and of course in the OTA version there is support for firmware update over WiFi. It is a rather small application, and not the critical at all - it just controls my curtains (all 8 of them - trust me, this ESP32 with a Web server per ESP32-C6 board is miles better than Somfy’s own solution…).

So ny ibky questions is: What is the blinking/flashing of the Yellow LED meant to show when there is no battery connected and then of course no battery charging going on…? CPU load? Current over a certain level? or what?

2

If it’s the LED labeled “CHG” it’s blinking erratically because there’s no battery attached. The charger ic monitors the battery terminal voltage and since there’s no battery attached it sees a random changing voltage. When that random voltage is below 4.2 volts the LED will be on. If it’s 4.2 volts or higher, the LED will be off.

It’s a high impedance input so other electrical noise on the board can influence the randomness of the voltage the charger is seeing.

3

Thanks for explaining! Good to know why it behaves as it does…

4

Just looked at the schematic.

If the LED is annoying and you want to disable it, there’s a jumper on the back of the board to the left of the battery connector labeled CHG. Cut that between the two pads and that will disable the yellow CHG LED on the board. If you ever wanted to re-enable the LED, a blob of solder connecting both pads will restore it’s operation. :slight_smile: