Custom board based on nrf5340 CLAA not working after flashing the application

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Tue, 06 May 2025 14:19:43 GMT

Hi Simon,

One more thing I want to mention is that I need to restart the system after flashing to get the system to work. I think the debugger is holding up the system in some way while flashing. We can close this ticket now. Many thanks for your help!

Best,

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Tue, 06 May 2025 05:18:33 GMT

Happy to hear that. Let me know if you have any further follow-up questions or if we can close this ticket now.

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Mon, 05 May 2025 14:11:50 GMT

Hi Simon,

Thanks for your reply. I was also able to get stable SCK and LRCLK when I set I2S correctly. In regards to getting the board to work after flashing, I had to set the board to use the internal RC for the 32 KHz crystal after building because I don't have an external one.

Best,

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Mon, 05 May 2025 07:44:49 GMT

Glad to hear you got it working. What exactly changed for the board to be operational here? The 32MHz crystal you're using seems to be just fine, depending on what the load capacitors are set as.

Regarding I2S, what pins are you using for SCK and LRCLK on the nRF5340? And can you describe what you mean by these pins not being stable?

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Maria Gilje — Fri, 02 May 2025 13:15:50 GMT

Hello,

I'm just letting you know that Simon is away today and he'll return to you when he gets back next week.

Best regards,

Maria

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Tue, 29 Apr 2025 22:03:32 GMT

Hi Simon,

I was able to get the board working also after flashing. I do have a 32 MHz crystal (Seiko Epson Q22FA12800025) on board and it is connected to the nrf5340 chip as shown in the figure below. Can you help me check this is correct?

Also, I am trying to test my I2S interface but found out that the SCK and LRCLK is not stable. Is there a place I need to configure to use this external 32 MHz crystal as the main clock to provide stable clock signals? Thanks!

Best,

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Tue, 29 Apr 2025 09:17:57 GMT

Does your custom board have a 32MHz crystal onboard? If not, that might be why you're only able to see it when a debugger is connected, as in that case the custom board may source the 32MHz crystal from the DK.

If you do have the 32MHz crystal on your custom board, please double check that it is mounted correctly on the custom board, as a common mistake is that it is mounted 45 degrees off.

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Mon, 28 Apr 2025 23:01:47 GMT

Hi Simon,

I am now able to enter the main function as shown below in debugging by setting CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y and

# CONFIG_SOC_ENABLE_LFXO is not set because my board does not have an external 32kHz crystal.

#include <stdio.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>

/* 1000 msec = 1 sec */
// #define SLEEP_TIME_MS   1000

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)

/*
 * A build error on this line means your board is unsupported.
 * See the sample documentation for information on how to fix this.
 */
static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

int main(void) {
    if (!device_is_ready(led.port)) {
        return 0;
    }
    gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
    
    while (1) {  // Add infinite loop
        gpio_pin_set_dt(&led, 1);
        k_sleep(K_MSEC(1000));
        gpio_pin_set_dt(&led, 0);
        k_sleep(K_MSEC(1000));
    }
    
    return 0;
}

Now after building the application, when I debug, the process stops at the following lines of code in cmsis_gcc_m.h. When I hit continue, the on-board LED starts blinking as expected. However, when I just flash the same code instead of debugging, the code is not executed on the board. Do you have any idea why? Thanks!

/**
  \brief   Disable IRQ Interrupts
  \details Disables IRQ interrupts by setting special-purpose register PRIMASK.
           Can only be executed in Privileged modes.
 */
__STATIC_FORCEINLINE void __disable_irq(void)
{
  __ASM volatile ("cpsid i" : : : "memory");
}

Best,

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Fri, 25 Apr 2025 13:09:24 GMT

These inductors were not part of the schematics you uploaded for our review, so it was assumed they were not present. Either way, thank you for confirming it's not the DCDC inductors causing this. It should be fine to test the application for the MDBT53V-DB-40 as long as you make sure you use the board files for this board when building the application. There are no obvious issues with the build/flash log. Make sure you're doing a Pristine build when you build with the DCDC regulators disabled to make sure you overwrite the existing application.

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Thu, 24 Apr 2025 16:02:58 GMT

Hi Simon,

Thanks for your reply. I followed the recommended decoupling for nRF5340 CLAA chip, Config 2, when I designed the board. Are the two 10uH inductors L6 and L9 not related to the usage of internal APP and NET DCDC regulators? I am not an expert in PCB design so please correct me if I am wrong.

Also, I did take a fresh custom board and disable all regulators in the first flash but unfortunately the board also did not execute the code. Can you see anything wrong with my build and flash log?

I do not have a nRF5340 DK but I have a Raytac MDBT53V-DB-40. Does it also make sense to test the application on it?

Thank you very much for your help!

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Thu, 24 Apr 2025 13:10:06 GMT

You say you think you have the inductors connected to pin A9 and B6, but I don't see the inductors in your schematics nor in your gerber files, so please make sure whether they're there physically or not. If they're not, you should test on a fresh (unused) nRF5340 custom board since booting with DCDC might put it in an unrecoverable state.

Have you tried running your application code on an nRF5340 DK and see if it works on the DK, as that's generally a good way to narrow down whether the issue is in HW or SW.

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Wed, 23 Apr 2025 21:10:40 GMT

Hi Simon,

Thanks for getting back to me. I was able to try what Edvin suggested in the private ticket to set the DCDC regulators off but unfortunately it did not solve my problem. The LED is still not working, I am not able to directly write to registers and I am not able to debug as well.

Just want to mention that I am using a TPS62743 Buck Converter on another board which is connected to the board I uploaded in the private ticket to convert the voltage from the Lipo battery to 3.3V. And the output voltage is indeed measured to be 3.3V. I followed the recommended decoupling for nRF5340 CLAA chip, Config 2, when I designed the board. Hence, I think I do have inductors and capacitors connected to Pin A9 (DCCD) and B6 (DCC) which I believe are related to the usage of APP and NET DCDC regulators, as shown in the schematic I uploaded in the private ticket. Hence, I am only disabling the High-Voltage regulator by adding the lines below into a file called nrf5340_platform_nrf5340_cpuapp_ns.overlap in my application folder:

&vregh {
    status = “disabled”;
};

Please note that I also tried disabling all three DCDC regulators but the result turns out to be the same. When I build my project, I set the board target to be nrf5340_platform/nrf5340/cpuapp/ns which I created from the board of nRF5340 in nRF Connect and it is able to build successfully. I am attaching my entire application folder at the end so that you can see my board definition.

As you can see, I am setting P1.07 high in the main.c:

#include <stdio.h>
#include <zephyr/kernel.h>
#include <zephyr/drivers/gpio.h>


/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led0)

/*
 * A build error on this line means your board is unsupported.
 * See the sample documentation for information on how to fix this.
 */
static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

int main(void) {
    if (!device_is_ready(led.port)) {
        return 0;
    }
    gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
    gpio_pin_set_dt(&led, 1);

    return 1;
}

I configured this GPIO pin via DeviceTree which can be seen in nrf5340_platform_nrf5340_cpuapp_ns.dts:

/dts-v1/;
#include <nordic/nrf5340_cpuappns_qkaa.dtsi>
#include "nrf5340_platform-pinctrl.dtsi"

/ {
	model = "Custom Board auto generated by nRF Connect for VS Code (CPUAPP Non-Secure)";
	compatible = "arm,nrf5340-platform-cpuapp-ns";

	chosen {
		zephyr,sram = &sram0_ns;
		zephyr,flash = &flash0;
		zephyr,code-partition = &slot0_ns_partition;
	};

	leds {
		compatible = "gpio-leds";
		led0: led_0 {
			gpios = <&gpio1 7 0>;
			label = "led0";
		};
	};

	aliases {
		led0 = &led0;
	};
};

#include "nrf5340_platform-cpuapp_partitioning.dtsi"
#include "nrf5340_platform-shared_sram.dtsi"

&gpio0 {
	status = "okay";
};

&gpio1 {
	status = "okay";
};

&gpiote {
	status = "okay";
};

I was able to build and flash the application to my board but it is not executing. Below is my full build and flash log:

devzone.nordicsemi.com/.../build-and-flash-log.txt

Then I tried to connect to the board via JLink.exe via command line and turn on the LED by directing setting P1.07 to high:

w4 0x50004514, 0x00000080  # DIRSET (set as output)
w4 0x5000450C, 0x00000080  # PIN_CNF[7] - Standard output, no pull
w4 0x50004504, 0x00000080  # OUTSET (drive high)

I can connect to the board. However, after writing to the registers, when I read the values again, they are all zeros so the setting seems to fail:

J-Link>mem32 0x50004514,1
50004514 = 00000000
J-Link>mem32 0x5000450C,1
5000450C = 00000000
J-Link>mem32 0x50004504,1
50004504 = 00000000

One thing I noticed is that some of my other GPIO pins are high even if I do not set them high, for example the ones I connected to the castellated holes: P0.16, P0.15, P0.13 and P0.03. I am not sure whether this indicates any issues with my application or my board design.

Thank you so much for your help! Please let me know if you think there is anything else I can try to get my board working. Looking forward to your reply.

devzone.nordicsemi.com/.../7317.blinky.zip

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Tue, 22 Apr 2025 05:39:58 GMT

Hi again Ke

As Edvin suggested in the HW review ticket, please try following his suggestion to disable the DCDC regulator as per the instructions in this ticket. Note that you're using the one of the newer SDKs, so please start out with the new way of setting it. You can start following the guide from "Then you are using an NCS version where the new way of setting this applies."

For your questions in the other thread, yes these changes will also apply to custom boards and custom board files. Also note that if the board doesn't get detected enabling the DCDC regulator for a design without the necessary components present might result in the board not working as expected, so you should make these changes and test on a new nRF5340 SoC/custom board design.

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Wed, 16 Apr 2025 10:47:38 GMT

You can detect the board, if so, can you upload a full log when you try to flash the board so we can see what's happening when trying to flash the board?

Best regards,

Simon

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Ke Li — Tue, 15 Apr 2025 15:34:07 GMT

Hi Simonr,

Thanks for your reply. I am using a J-Link debugger to program it. I don't have a DK to test on so I directly program on my custom board. I am using the SDK v2.9.1 and the corresponding toolchain in nRF Connect SDK in VS Code to program the board. The build and flash process all showed successful message and did not get any errors.

Actually, I can detect the board after plugging in the J-Link to my laptop. The power on the board is also measured to be 3.3V.

I will talk with my collaborators to see whether we can share our schematics and gerber files. Thanks!

Best,

RE: Custom board based on nrf5340 CLAA not working after flashing the application

Simonr — Tue, 15 Apr 2025 11:51:43 GMT

If it's a brand new/fresh SoC there shouldn't be any lock/protection on it, and flashing it should be pretty straight forward. What are you using to program it, an nRF53 DK or similar, or a J-Link debugger? Have you been able to flash a similar project onto a DK to test that the firmware works correctly there, or are you gunning straight for the custom board? Per the product specification there shouldn't be anything special about the P1.07, so it just seems the board hasn't been flashed correctly.

You can try running an nrfjprog --recover command from the command line, but if you can't detect the board in the first place my guess is there's something wrong with the HW, so perhaps a HW review would be the first step here. You can either create a separate private ticket for that or we can make this ticket Private so you can share schematics and gerber files here.

Best regards,

Simon