nRF51822 controller connection through UART/SWD.

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Thu, 10 Dec 2020 14:24:55 GMT

Thanks for the help. But the problem turned out to be the difficulty of working with a production device that I only have half the information for. In order to flash the device, I have to turn it on which runs the current program immediately. When I flash, the flashing happens somewhere in the middle of that program running. Who knows where? This caused the saved data (in particular bonding info) to get corrupted. Restarts basically did not get pass reloading bonding. I removed all the code related to bonding (so I connect unencrypted) and it worked. So I did not erase the Softdevice and I did not fry my chip with my clunky soldering of the SWD interface.

I have learned to give a lot more respect to those hardware engineers that can solder micro wires to micro pins.

RE: nRF51822 controller connection through UART/SWD.

Kenneth — Thu, 10 Dec 2020 13:27:20 GMT

Erasing sectors means that it will erase only those flash sectors (4kB flash pages) that overlap with the firmware you are trying to program. Typically this will keep other parts of the flash intact (e.g. bonding information and softdevice will not be replaced or erased if you program the application).

In Keil you typically have a drop down box where you can either program the precompiled BLE stack (e.g. flash_s132_nRF52_x.x.x._softdevice) or the application (e.g. nrf528322_xxaa), this is chosen like this:

If the softdevice stack is chosen you should flash the softdevice, do not press compile! If you press compile the softdevice hex file found in \components\softdevice will be erased, and you can no longer flash it. In that case you need to unzip those folders from the nRF5 SDK zip file again.

If the application is chosen, then you can compile and program the application.

Typically you program the softdevice stack first, and then you only need to work with the application firmware.

To erase entire flash (softdevice and application) you can click:

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Tue, 08 Dec 2020 15:28:29 GMT

Andreas,

After some searching I found that Keil is set to erase sectors. But I do not know what 'sectors'. All I have is an address range.

I cannot copy-paste so its hard to get this hand-typed copy right. nRF51xxx with Range is 0000...0H to 001FF...FFH. When I click on 'add' I see there are three options including SoftDevice. When I add that it has the same range as the already included nRF51xxx option. Would suggest that SoftDevice was erased as well. But I am not sure if that is not relative to something else.

If SoftDevice is gone can I use Keil to re-install is or DO I need to use the nRF tool?

Well, using the nrfTool is says that I don't need to load SoftDevice. So nrf51822 is probably damaged. But since I have no idea what I am doing and working with a chip in a production device without the tools one really needs for this job, I have no idea.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Tue, 08 Dec 2020 08:28:00 GMT

Hi,

Sounds like you might have reprogrammed the device, possibly erased the flash where the Application and Softdevice was stored. You should look into the settings in Keil, if it does a full erase, or partial and if so which sectors. In this case you need to reprogram the Softdevice also.

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Mon, 07 Dec 2020 11:59:38 GMT

The error was solved by googling which led me to a post in this forum. Found that I needed to set the debug mode to 'SW' instead of Jlink or whatever it was. Doing that solved the 'cortex' error.

I still have a slew of other issues as there is a separate sensor MCU running independently of the BLE. I have managed to mess it up enough that the BLE is no longer advertising. Probably did something in the starting the debugger that the BLE stack got corrupted.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Mon, 07 Dec 2020 11:35:24 GMT

Hi,

The header 'layout' follows the Arduino shield standards, allowing 3rd party PCBs to be popped on top and connect to the nRF52 and/or IF MCU through the GPIO headers. A target nRF51 on such a shield would be able to be debugged through the P20 header, but it can of course be used with fully external targets as well.

The error you get could be due to the wiring (e.g. swapped SWDIO and SWDCLK) or due to missing power supply of the target. Could you try nrfjprog instead? Install if you do not have it (write 'nrjprog -v' in a CMD window) and run

nrfjprog -f NRF51 --readregs

Do you get any error? Hopefully that should be more indicative.

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Thu, 03 Dec 2020 16:47:48 GMT

It turns out I can get power from the batteries on the production device. So I have used the VTG pin on P20 to connect to the VDD 'pin' on the production device. The DK user's guide mentions that P20 is for 'shield targets' but I am not sure what that means.

I also have limited equipment and tools to make the solder connections on the target board. They look okay but its hard to tell.

So now I run the Kiel IDE with the project and plug the USB cable into the DK. Yellow led comes on. I start the Start/Stop debug session on the Keil IDE and get the error 'no Cortex-M device found ...'. Now this project was provided by the developer of the production device so I figure I am using the DK wrong or have not done a solid job of soldering.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Thu, 03 Dec 2020 15:47:38 GMT

Hi,

OK, sounds like it should be fine. If the target is powered it should be fine to power it using the DK, if 1.8V it will be out of range for the debugger on the DK anyway.

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Wed, 02 Dec 2020 09:47:45 GMT

Thanks for that information. I do not know if the target is self powered when trying to flash new code. I am asking the company, but I do not believe it is. Pressing the power button triggers all kinds of sensor activity that I have no control over and has nothing to do with the BT module. So I am pretty sure I have to power the target from the DK. I assumed that I would have to wire the VDD of the DK to VDD of the target to do that. If self powered, I would use VTG of the DK to VDD of the target. But I guess it is slightly more complicated than that.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Wed, 02 Dec 2020 07:47:09 GMT

Hi,

VTG is the input of the debugger, that is to be connected to VDD on the debug target. If the target is supplied and powered by its own supply/battery/etc. then this will work, if not then you can connect VDD (on the DK) to VTG (and by extension VDD on the target) to power the target. See as an example the wiring in this case.

Note that you might want to cut SB9 to not power the nRF51 on the DK itself. This can be reverted by shorting SB9, or plugging a jumper across P22:

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Tue, 01 Dec 2020 15:44:06 GMT

My DK has both VDD and VTG pins. Which is the correct one to use?

RE: nRF51822 controller connection through UART/SWD.

Andreas — Tue, 01 Dec 2020 08:38:17 GMT

Hi,

[quote user="brianreinhold"]So what you are saying is that I could take a USB cable connected from the PC and wire it directly to the SWD pins on my production device (I know where to solder the connections)[/quote]

No, the USB port on the PC will not understand the SWD protocol. You can connect the SWD pins on your debugger to SWD through an USB cable, obviously this will not work as a 'normal' USB port (e.g. by a compunter) and for that it might not be an ideal solution as the debug USB port might be confused with a normal USB port, care must be taken for this to handle the 5V bus voltage in case it is incorrectly inserted into a normal USB port.

[quote user="brianreinhold"]Alternatively, I could connect the USB cable to the DK and wire the P20 and P19 pins to my production device. The latter sounds easier and safer as I assume that all voltage and power supply issues are worked out.[/quote]

Yes, this would work. The interface MCU on the DK acts as a translator, and will translate the communication from the PC (over USB) into SWD which is needed by the nRF51822 target. This needs SWDCLK and SWDIO for communication, and VDD (called VTG by the debugger) and GND for reference voltage. Note that the VTG connection on the debugger does not supply the target, you must make sure to do this externally.

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Mon, 30 Nov 2020 12:30:41 GMT

I DO have the DK. My production target also has its own power (it is a real market device) but the device will not be on when flashing. So what you are saying is that I could take a USB cable connected from the PC and wire it directly to the SWD pins on my production device (I know where to solder the connections). Will there be a power problem? I've seen in this forum somewhere that the voltage needs of the nrf51822 are not that supplied by USB.

Alternatively, I could connect the USB cable to the DK and wire the P20 and P19 pins to my production device. The latter sounds easier and safer as I assume that all voltage and power supply issues are worked out.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Mon, 30 Nov 2020 10:30:38 GMT

Hi,

Not sure I understand correctly, but the DK has a debugger IC on it (the one with the sticker) that translates the information received from Keil over the USB cable into SWD. Hypothetically you could direct SWD over a USB cable from the debugger to your target nRF51, the nRF51 just needs an electrical connection to the SWD, SWDIO, VDD and GND pins on the debugger.

You can use P20 or P19 on the DK to program or debug an external target (instead of the nRF51 on the DK itself), see section 6.10 in the DK User Guide.

Best regards,
Andreas

RE: nRF51822 controller connection through UART/SWD.

brianreinhold — Sun, 29 Nov 2020 14:48:07 GMT

I need to do something similar to the above. I have a finished pulse oximeter using the nRF51822 on a YJ-14001-nrf51822 daughter board. The device is to test a new BLE protocol specification and I have been provided with the original software in a Keil project. I need to replace the existing BLE protocol with the new protocol specification.

According to the company, I can flash the software using SWD. They have given me the input soldering points on the daughter board to make the SWD connection on the Pulse OX. Now what I need to do is interface that to the PC. I have no idea how to do this.

From this discussion it appears that I cannot repurpose a USB cable and flash the device from the Keil IDE even though it supports SWD via USB when using a DK..

How do I do this directly to the nrf51822 SWD contact points? Do I need additional hardware to go from USB to SWD?

Thanks. If this is not answered in a few days (old post) I will make an additional post.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Thu, 24 Oct 2019 08:12:07 GMT

Hi,

The programmer needs SWD, SWDIO, VDD and GND, no matter which one you use.

Also there are some de-facto standard connectors for this that might be interesting, which all incorporate the needed signals. See as an example J-link needle adapter and 9-pin cortex-M connector.

Best regards,

Andreas

RE: nRF51822 controller connection through UART/SWD.

Namitha — Thu, 24 Oct 2019 05:44:55 GMT

Ok thank you..one more thing i need to know which all pins i need to take out from the nRF51 controller in order to program with these programmers.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Wed, 23 Oct 2019 08:21:53 GMT

Hi,

For production programming you need a production programmer, the DK debugger license only covers use during development. The connection towards your board will be the same though, it will just be a different programmer instead of a DK.

You might find this getting started guide useful.

Best regards,

Andreas

RE: nRF51822 controller connection through UART/SWD.

Namitha — Wed, 23 Oct 2019 05:26:23 GMT

But for mass production we need to program nRF51 on our PCB individually. I want to know how to connect, by using DK board can we program the controller which is in our PCB..kindly help us with this.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Tue, 22 Oct 2019 11:28:32 GMT

Hi,

I am not quite sure I understand what you mean, but if you have a nRF51-DK you have all that you need to program/debug your nRF51822 board, and the nRF51822 IC that sits on the nRF51822. Some slight modifications might be needed on the DK in order to have the interface MCU communicate with the external nRF51822 over UART.

The principle for both programming a nRF51822, and communicating with a nRF51822 over UART is the same, regardless if it is your custom PCB or a nRF51-DK. See this blog post for details. The difference is that on the DK, UART and SWD(for programming/debug) lines are hard-wired to the nRF51822 that is on the DK itself. If that NRF51822 sits in parallel with your custom board nRF51822 then the communication will be disrupted.

Best regards,

Andreas

RE: nRF51822 controller connection through UART/SWD.

Namitha — Tue, 22 Oct 2019 04:54:16 GMT

The thing is if i have the nRF51 DK board can i program the nRF51822 controller which is on the DK board directly from PC using the nRF51822 UART pins and USB to UART converter.

The interface MCU will be bypassed by cutting the soldering edge.

Is it possible to do kindly reply or i need any other software or debugger to program the controller.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Mon, 21 Oct 2019 12:26:31 GMT

Hi,

There is a nRF51822 on the DK itself which you will need to disconnect from the UART lines in order to use UART with your external nRF51822 board. Or you can just remove the power supply for the on-DK nRF51822, there are solder bridges for easy cutting of all relevant lines.

For programming of the external board SWD will be used, this can be done in parallel with the nRF51822 on the DK.

Best regards,

Andreas

RE: nRF51822 controller connection through UART/SWD.

Namitha — Mon, 21 Oct 2019 10:50:05 GMT

Thanks for the reply.

In nRF51 DK board will it support UART connection for programming even if we bypass the connection of MCU and try direct programming form pc to nRF controller.

RE: nRF51822 controller connection through UART/SWD.

Andreas — Mon, 21 Oct 2019 08:46:09 GMT

Hi,

You need to translate the SWD interface and the UART interface to something the PC understands. For SWD a J-Link debugger is typically used, other SWD debuggers can be used but you might experience various incompatibility with our other tools. For UART any UART to USB translator can be used.

nRF51-DK comes with an on-board J-Link debugger and UART translator combo MCU for easy interfacing. Furthermore it is 100% supported with all our tools. If you do not have any debugger or UART translator I recommend getting your hands on a nRF51-DK, or even nRF52-DK (compatible with external nRF51 boards).

The setup is the same though, you need to connect SWD as explained below to the debugger, no matter which debugger is used, and UART RXD->TXD and TXD->RXD no matter which translator is used.

Best regards,

Andreas

RE: nRF51822 controller connection through UART/SWD.

Namitha — Mon, 21 Oct 2019 06:16:13 GMT

OK thank you...but i am not using the DK board..i have the nrf controller on my pcb..i have taken out the swdio and swdclk pins to the connector along with the uart pins..kindly help me with how to connect these pins from the PC.