nrf52840 module - using circuit python on blank chip?

[RainySun]

Hey, I plan on ordering nRF52840: https://www.adafruit.com/product/4078
I have chosen to order this because of its smaller footprint, and I can solder it onto PCB.
The issue I have with this is that I do not know how to install the firmware. It mentions " The module comes with a blank chip", and to use J-Link programmer and the Nordic SDK.
Is there a guideline that can help me out? Can I even install Circuit Python to this blank chip?
Hope to hear your response.

[dastels]

Your answer is there: " J-Link programmer and the Nordic SDK". It's not beginner level stuff.

As for soldering it to a board... also not beginner stuff as the connections are on the bottom of the board.

Here's a guide that talks about j-link, albeit with the SAMD21. https://learn.adafruit.com/make-a-simpl ... for-the-m0

Nordic's site should have more information. See https://www.nordicsemi.com/Products/nRF52840.

Dave

[danhalbert]

The nRF52 bootloader repo includes instructions about how to flash the bootloader: https://github.com/adafruit/Adafruit_nRF52_Bootloader

[RainySun]

Hey, I received nrf52840, https://www.adafruit.com/product/4078, and plan to work on it. Something doesn't add up.
Looking at the Raytac website, https://www.raytac.com/product/ins.php?index_id=24, it shows that the crystal oscillator is already added to the module that I bought.
When comparing to the Feather nrF52840, the crystal oscillator is soldered outside.
Do I need a separate crystal oscillator?

[danhalbert]

The RayTac module includes a 32 MHz crystal. That crystal is necessary for proper functioning of the BLE radio. Optionally, the nRf52840 can also use a 32 kHz crystal. The Feather includes that crystal. The 32 kHz crystal allows more accurate time-keeping, and when the chip is asleep, its oscillator uses less power than runing the 32 MHz clock and synthesizing 32 kHz from it.

So the Feather does have the 32 kHz crystal. The Circuit Playground Bluefruit does not (but does have a 32 MHz crystal on the board because it does not use module). So those are examples of both choices.

[RainySun]

Hey Dan,
Just want to confirm something. isn't raytac module and the adafruit nrf52840 module the same.
The raytac module has 32Khz crystal soldered, not 32Mhz. I got the above schematic from Raytac.

- Nevermind, you are right. It has 32Mhz crystal on the module.
Just reviewed the document provided by Raytac. I believe they have a mistake in their schematic, they should be showing 32Mhz instead of 32Khz.

[RainySun]

Does the mean that adafruit have already removed the 32Mhz on the Feather nrf52840 module?
I guess I need to do the same.

[danhalbert]

Does the mean that adafruit have already removed the 32Mhz on the Feather nrf52840 module?

I'm not sure what you mean. We haven't removed anything.

There is a 32 MHz crystal in the RayTac module. We use the same or similar module on the Feather.

The RayTac module can connect to an off-module 32 kHz crystal, in addition to, not instead of, the 32 MHz crystal. We provide a 32 kHz crystal and its associated components on the Feather nRF52840. If you don't use a 32 kHz crystal, do not install the X2. C12, C13 components. The screenshot you're showing is about using the internal 32 kHz RC (not crystal) oscillator, which does not need or use these components (and possibly their presence may affect it).

[RainySun]

Thanks Dan for the clarification.
Now that I have an understanding, I still have a question regarding nrf52840.
If we look at feather or Itsybitsy nrf52840, it has QSPI component. Whereas, if I look at Raytac document, the schematic doesn't have the 2Mbyte QSPI component.
I recently bought the following component:
https://www.adafruit.com/product/4078?g ... X_EALw_wcB
Can I add the following QSPI component to what I recently bought? Is there a specific type of QSPI that I need to buy?
https://www.adafruit.com/product/4763