RP2040 Node Power Consumption

[so1der]

Hello there! So I have a prototype of Meshtastic node using RP2040 + Ra-01. I heard that RP2040 consumes much less power than ESP32, so I decided to give it a try. After assembling it, I measured the current on the 3.3V bus - it was around 40 mA.

I also have a ESP32 based Meshtastic node - after disabling OLED screen and Bluetooth, it consumes around 50-60 mA on the 3.3V bus.

So the difference is around 10-20 mA. That's really it, or my RP2040 node consumes more than it should? If someone has an RP2040 based node, and can provide me with a current measurements, I would really appreciate it!

[so1der]

While researching this topic deeper, I saw that there is rpipico-slowclock variant, that reduces RP2040's Clock Speed from 133 MHz down to 18 MHz. The current consumption in that case decreases drastically, from ~40 mA down to 18.5 mA! I am very happy with this result!

Alas, if I understand the code correctly, it also disables RP2040's USB:

main-rp2xx0.cpp:

    /* Turn off USB PLL */
    pll_deinit(pll_usb);

And since RP2040 doesn't have Bluetooth or WiFi, the only way to setup node now is to use an external UART adapter, such as CH340, or CP2102.

Aside from the USB, are there any downsides of using such low clock speed?