I’m figuring out how to best use M1n in a multi MCU setup. I can power the whole K210/M1n on/off or I can use low power mode. Is there a datasheet/github page with more information?
K210 does not have low power mode. You can only lower the power consumption by lowering the clock frequency (which can be done in software).
You can controll the power to the K210 with an external circuit or microcontroller.
For example, I’m using K210 - ESP32 combination where ESP32 turns on/off the power to the K210.
As ESP32 has quite good power management, you can easily achieve deep sleep modes with <10 uA power consumption. In my case, ESP32 also provides wake-up functionality and very fast WiFi access ower SPI interface.
Other microcontrollers could be used too, or even a simple RTC chip (which can wake-up K210 at programmed time) combined with a power on button or some power management chip.
That’s a shame. The M1W has Wifi already so it seems like a waste to double up on that functionality, not to mention writing two sets of firmware. Your suggestions make sense though.
Could the reset pin be used as a power off?
In reset K210 still draws significant amount of current (10s of mA).
It is quite easy to design a power management circuit with external RTC chip like PCF8563 and achieve very low (< 1uA) power off mode, still being able to wake up at programmed time and/or with an external button. The cost is < 2 US$ (PCF8563+crystal+mosfet).
Using ESP32 has many advantages, and the price is almost the same (< 4 US$). Using ESP32-PICO-V3 you need only the slightly larger board space (~ 1 cm2). The power consumption in deep sleep mode is also slightly larger (~6 uA).
I think using the M1 module (without Wifi) + ESP32-PICO-V3-02 is an optimal sulution for low power K210 board with high speed WiFi connectivity. I’m planning to release an open-hardware project based on that combination early next year.
I completely agree with you. I’m just thinking out loud. I’m just coming at it from a design direction with a lot of holes in my electrical engineering knowledge.
I plan to come out with something using 2 M1n modules, an ESP32 and an nRF52840. I use the ESP32 as an optional module and the nRF module as the coordinator much like you use the ESP32.
My current plan is to switch the MCUs on/off using a MOSFET. I’m starting to wonder if I need the reset for anything, since I can just power off/on. It seems for the ESP32, I’d use the EN, but for the M1n I control power supply.