Standalone power

ramg · September 15, 2020, 6:39pm

Hi all!.

I´m developing on Arduino.
Everithing goes well when connected to PC vía USB.
When I power the board using a simple USB charger or/and a 3.7V LI-Ion battery, the board doesn’t boot (I think because no led´s).

With default firmware, same battery it, hasn’t got a problem.

Any clue?
Thanks.
Ramiro

nero · September 16, 2020, 3:12am

Hi,
What the default firmware do you use? I’am not clear what board doesn’t boot mean. If you download the bootloader from our github, it must be show the usb com port.

ramg · September 16, 2020, 11:18am

When using default firmware I mean this: https://downloads.rakwireless.com/en/Cellular/RAK5010/Firmware/

So, with default firmware, once y power the board with a li-ion 3.7V battery, the leds indicate the boot process is correct.

But, with this bootloader: https://github.com/adafruit/Adafruit_nRF52_Bootloader/releases/download/0.3.2/feather_nrf52840_express_bootloader-0.3.2_s140_6.1.1.hex
the board boot’s only if I plug it to the PC USB and open a serial connection to it!

nero · September 17, 2020, 1:20am

ok, I see. Because our default firmware is optimized. It has the good performence on 5010. But about Arduino, we just run it successfully without optimized. We will optimize it later. It is great if you can develop it on RAK5010 based our work.

ramg · September 17, 2020, 8:26pm

Hi.
In Adafruit bootloader github, Readme file “says”:

There are two pins, DFU and FRST that bootloader will check upon reset/power:
…

DFU = HIGH and FRST = HIGH : Go to application code if it is present, otherwise enter DFU with UF2

I don’t know in Variant PCA10056 where are those signals, and state of them.
Do you?

nero · September 18, 2020, 7:40am

Hi,
According to the code of adafruit, P11 is for DFU and P12 is for FRST. I’ve checked the layout of 5010. They are like this. P11 is for UART CTS of BG96, P12 is for LED.

But in our demo, we do not use these two pin. They should be default state. According to nordic SDK, they should be:

So if you want to use DFU funtion, I advise you change the Pin num in code of adafruit, point to the rest pin for user. Like IO1 to IO4. But remember, the four pins is useful unless input 3V3 to Vref closed IO1~IO4.

Below is the circuit diagram of 5010.
https://downloads.rakwireless.com/Cellular/RAK5010/Hardware-Specification/

And other details
https://doc.rakwireless.com/rak5010-wistrio-nb-iot-tracker/quick-start-guide

ramg · September 18, 2020, 12:40pm

The intention is not using DFU, instead is to solve the boot to application code when power the board using a battery only.

Changing adafruit bootloader is not suitable, because of maintennance. What I need is to get P11 and P12 on HIGH always, but I think is impossible due to the layout of 5010.

I can conclude that using Adafruit bootloader is only possible when connected to PC USB.
Right?
Thanks

nero · September 21, 2020, 2:13am

Hi,

I have test, it can be powered with battery only without any problem. In the setup, you just need delete the “While (! Serial) delay(10)” and add just “delay(1000)”. Because it waits for a usb connection forever.