Customize nRF51 MasterBootSwitch

[vinzenzm]

Hello Bitcraze Team,

we are doing large scale swarming research at our institute and have 50 crazyflies in the system.
They are placed on wireless chargers and all have QI charging decks attached.
We are currently working on some functionalities to further streamline our processes.
Currently we have to manually switch on all crazyflies before testing, which takes quite some time, and we already have some buttons failing to function.

One of our students had the idea to detect the powering of the QI deck in order to switch on the crazyflie.
After I took a look at the nrf software architecture i found this piece of the low-power nrf firmware (https://github.com/bitcraze/crazyflie2-nrf-mbs) which currently handles button presses in order to switch on the "high-power-nrf" and stm.

After checking the schematic https://www.bitcraze.io/documentation/hardware/crazyflie_2_1/crazyflie_2.1_schematics_rev.b.pdf
i saw that the PGOOD signal of the charge-controller (BQ24075) would provide exactly the functionality we need.

Apart from polling the button pin the MBS code could also check the PGOOD pin and power on the system if held high/low for e.g. 1 second.

I would like to try this out, however I would like to avoid having to solder the debug connector to all our crazyflies.

Is there a way to flash the MBS code wirlessly with the cfloader like it is possible with nrf-bootloader, nrf-firmware, stm-firmware?

I would highly appreciate ideas or other approaches regarding our use case.

Vinzenz

[tobbeanton]

Nice addition! Unfortunatly the only way to flash the MBS is using a programmer. The debug adapter has some 1:1 NRF pins on which you can solder some pogo pins and connect to the (without soldering) CF2 to make the process smoother. Do you understand what I mean?

[vinzenzm]

That actually sounds very interesting.
As far as I understand this line of the button.c in nrf firmware sets up the sense mode for button pin:

NRF_GPIO->PIN_CNF[BUTTON_PIN] |= (GPIO_PIN_CNF_SENSE_Low << GPIO_PIN_CNF_SENSE_Pos);

if i set this for the PGOOD pin as well (maybe trigfer on edge or high) nrf should power on same as with button press.

Wouldnt this call MBS Code immediately and register it as short press and therefore also boot stm?

Either way nrf would be able to receive radio packets and i could broadcast stm power on on all channels?

(STM_OFF probably isn't good if system should be off for more than a few hours, and we let the crazyflies powered on anyway; maybe worth an idea for faster charging and general health of the battery and BQ24075 health)

[tobbeanton]

Wouldnt this call MBS Code immediately and register it as short press and therefore also boot stm?

Yes, and it does and it is registered as no-press. For some reason the first Crazyflie I tested with did not but the other did.

So the PGOOD wakeup solution should work quite well for you.

[vinzenzm]

Thank you so much for the ideas and checking it out.
I will try to set this up as soon as possible.

[vinzenzm]

I had my Version running on since March on our full fleet, which worked great, never had issues with it.
Thanks for including this feature into official firmware in bitcraze/crazyflie2-nrf-firmware#115

[enyanil]

Thank you for your support and contribution @vinzenzm!