nRF52840 custom hardware Reset using External switch

RE: nRF52840 custom hardware Reset using External switch

Einar Thorsrud — Fri, 15 Jan 2021 12:39:40 GMT

Hi Rohit,

[quote user="Rohit Rajapure"]What did is connected my Dev-kit and open command terminal copy-pasted the suggested command and for both addresses, I got - 00000012 (hex).[/quote]

That's good. That means that pin reset is enabled there. It should be the same on your custom HW if you flash the same hex, but it would be good to confirm.

RE: nRF52840 custom hardware Reset using External switch

Rohit Rajapure — Fri, 15 Jan 2021 10:27:03 GMT

Hi Einar,

Okay, sorry for my mistake.

What did is connected my Dev-kit and open command terminal copy-pasted the suggested command and for both addresses, I got - 00000012 (hex).

I will connect the custom device and follow the same steps.

I will get back to you.

Thanks and Regards

Rohit R

RE: nRF52840 custom hardware Reset using External switch

Einar Thorsrud — Fri, 15 Jan 2021 10:15:07 GMT

Hi Rohit,

[quote user="Rohit Rajapure"]

Unable to open this, If I click on this it disappears fast.

Not understanding exact procedure.

[/quote]

You cannot double click it, it is a command line tool. To use nrfjprog first install it, and the installer should automatically add it to your path. Then open a terminal window. When using windows, you can click the start button and write "cmd". Then you get a terminal window.

In the terminal window write "nrfjprog.exe --memrd 0x10001200" and press the enter key. Afterwards, do the same with "nrfjprog.exe --memrd 0x10001204"

RE: nRF52840 custom hardware Reset using External switch

Rohit Rajapure — Fri, 15 Jan 2021 10:12:25 GMT

Hi Einar,

I had gone to this file path,

C:\Program Files (x86)\Nordic Semiconductor\nrf-command-line-tools\bin

Unable to open this, If I click on this it disappears fast.

Not understanding exact procedure.

[quote userid="7377" url="~/f/nordic-q-a/70431/nrf52840-custom-hardware-reset-using-external-switch/289352#289352"]There is one more detail I forgot to mention. After programming and thereby writing to the PSELRESET registers the device needs to be reset once (by power-cycle or debug reset) in order to enable pin reset,[/quote]

- We tried this but did not work. But we will try this again, program the hardware first power cycle it again and check.

Thanks and Regards

Rohit R

RE: nRF52840 custom hardware Reset using External switch

Einar Thorsrud — Fri, 15 Jan 2021 08:56:41 GMT

Hi Rohit,

[quote user="Rohit Rajapure"]- Can you please give me steps on how to check this? Sorry, but the point is not clear on debugger how to check.[/quote]

Yes, you can refer to the snippet from my previous post.

You need to check two registers, PSELRESET[0] which is address 0x10001200 and PSELRESET[0] which is address 0x10001204. That is done using nrfjprog as demonstrated in my initial reply. If both registers are 00000012 (hex) as you see in my example, then the device is correctly configured for pin reset.

There is one more detail I forgot to mention. After programming and thereby writing to the PSELRESET registers the device needs to be reset once (by power-cycle or debug reset) in order to enable pin reset, as the PSELRESET registers are only read during startup.

Einar

RE: nRF52840 custom hardware Reset using External switch

Rohit Rajapure — Fri, 15 Jan 2021 05:33:21 GMT

Hi Einar,

Thank you for the response,

Okay, I will re-check this.

[quote userid="7377" url="~/f/nordic-q-a/70431/nrf52840-custom-hardware-reset-using-external-switch/289209#289209"]For HW, can you check that P0.18 actually becomes 0 V when pressing S6?[/quote]

- As shown in the schematic, P0.18, P0.19, P0.21, P0.23, P0.25 are shorted. And there is no way that we can check specifically on P0.18 as IC is soldered. but we have a RST Testpoint in custom board and it goes to low when switch S6 is pressed.

[quote userid="7377" url="~/f/nordic-q-a/70431/nrf52840-custom-hardware-reset-using-external-switch/289209#289209"]For SW, you can start by checking that the UICR register is actually correctly configured by reading it out with a debugger?[/quote]

- Can you please give me steps on how to check this? Sorry, but the point is not clear on debugger how to check.

Where I can find this address?

- And per schematic can I short P0.18 and P0.25 pins and make connection on Dev-kit. Or will it cause any damage to Dev-kit because I have single Dev-kit so.

- Also, If I just use If BOOT/RESET button from Dev-kit then Dev-kit gets reset properly without any issue.

But unable to execute same on custom hardware.

Thanks and Regards

Rohit R

RE: nRF52840 custom hardware Reset using External switch

Einar Thorsrud — Thu, 14 Jan 2021 13:02:44 GMT

Hi Rohit,

This looks OK from a HW perspective. Pushing S6 will pull P0.18/RESET down to GND, asserting it. And it also looks correct from a SW perspective, with CONFIG_GPIO_AS_PINRESET defined. I think we need to double check a bit.

For HW, can you check that P0.18 actually becomes 0 V when pressing S6?

For SW, you can start by checking that the UICR register is actually correctly configured by reading it out with a debugger? You should read out the value of the PSELRESET registers and see that both are 0x00000012 as shown here:

C:\Users\eith>nrfjprog.exe --memrd 0x10001200
0x10001200: 00000012                              |....|

C:\Users\eith>nrfjprog.exe --memrd 0x10001204
0x10001204: 00000012                              |....|

Is that the case?

Einar