Building a development board to flash the nRF52833

[Daniel V]

My current project is to build a simple BLE LED controller. The goals of this project are to familiarize myself with lower level modules and to practice designing/building circuits. That is why I am not using the evaluation board and am instead trying to build my own. As a warning/preemptive apology, most of my BLE experience is with BeagleBones and Arduinos, and I am generally a novice with electrical engineering. 

My plan was to use Fanstel's BM833 module, which is built around the nRF52833 chip. I would design/print a simple breakout board for the pins that I need from the chip. The bulk of the project would be designing and printing a custom development board that I would use to program the chip from my Mac. I plan on using the FT232RL USB to serial breakout board and adding an EC3-.327 32kHz crystal oscillator. 

I am currently stuck on figuring out how to prepare and upload a program to the chip from Segger. I have been following this tutorial (among many others), but that one assumes I have the development kit. Could you offer any guidance on how to design my own device? Would I need a J-Link programmer like this one no matter what? How would I use that? 

I am also still a little confused about the difference between a bootloader, a SoftDevice, and an application. This thread says:

When you want to send data over BLE or ANT, you first flash BLE softdevice or ANT softdevice and then put you application on top of that. With that you can send data over BLE or ANT. You do not need any bootloader to do this. You need to program the device by connecting a programmer to the SWD programming interface on the nRF51.

So do I not even need a bootloader? Do I need to first flash the SoftDevice (I was thinking S113) and then upload the application? The tutorial I linked to above shows how to upload/run using Segger and a development kit, but the goal of my project is to use Segger with my own device and avoid the dev kit.

Any and all advice would be greatly appreciated!! I'm having trouble getting a bird's eye view of the project, and it's getting a bit maddening...

[Sunil vignesh]

Hi Daniel,

To answering your question

Daniel V said:

prepare and upload a program to the chip from Segger.

preparation just look at the examples from infocenter and build it.  link

uploading to custom board where you need either development board of nRF or J-Link

if you have DK

link1

link2 . 

in link2 you see that you can use P19. pin to program custom board.

connection like this

Daniel V said:

do I not even need a bootloader?

Yes, it is need when your going to update the code (application or Softdevice or Bootloader ) over the Air. (OTA / DFU)

otherwise it is not necessary

only SD + application is enough to run and test the code. link    link2

[Daniel V]

Thank you for your great answer! Is it possible to flash the chip without a JLink or the development kit? The JLink is very expensive and the development kit defeats the purpose of this project.

[Nguyen Hoan Hoang]

This is an alternative solution.  Instead of JLink, you can use the IDAP-Link to flash or put IDAP-M (IDAP-Link module version) on your board to make yourself a dev kit. The IDAP has software made for flashing nRF5x series.

[Daniel V]

Nguyen Hoan Hoang

Ah so if I used the IDAP-Link I would not even need the FT232RL USB to serial breakout board, right? 

According to page 13 of the IDAP-Link user guide, I'd be dealing with the IDAP-Link Rev. 3 with 16 pins. I am trying then to figure out which pins on the nRF52833 correspond to which of the pins in this IDAP-Link connector table:

 

In other words, I am trying to map 1-16 in this table to the correct pins on the BLE module, with pins/pin functions described on pages 19-21 of this document. I think I can infer some of the pins:

• 2 maps to pin 43
• 4 maps to pin 22
• 7 maps to pin 40
• 11 maps to pin 32
• 12 maps to pin 31

Beyond that, unfortunately, I am lost. I don't see any mention even of RTS/CTS or other labels in the data sheet. Is there some other reference for the correct connections?

Again, thank you for your help, and I really appreciate your patience. 

[Nguyen Hoan Hoang]

Is exactly. It has a UART to USB bridge.  You will see a com port on your PC. T_RXD mean Target RX, connect you RXD to it.  The same with TXD, RTS, CTS

[Daniel V]

Nguyen Hoan Hoang, I am confused about the other pins in the table above. I do need to connect them, right? Which pins on the nRF52833 do they connect to? I can’t find any reference anywhere. 

[Nguyen Hoan Hoang]

the other pins are the swd/jtag for flashing. The IDAP-Link supports both mode SWD and JTAG.  The nRF series programming are in SWD mode.  Other MCU such as the LCP1769 or STM32 has JTAG mode.

SO you need to connect TVcc, SWDIO SWDCLK, GND for flashing and debugging your board