Issues with programming/operation of custom PCB with nRF52832

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Wed, 28 Sep 2022 01:57:32 GMT

OK, got this all working now. There were two issues:

1. Needed to add CONFIG_BOARD_ENABLE_DCDC=n to my prj.config file

2. Needed to power cycle my custom board after flashing to force a hard reset. Without this second step, the code just doesn't seem to run as expected

Cheers,

Mike

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Mon, 26 Sep 2022 07:43:28 GMT

Hi Kazi,

I did in fact try that earlier, and it made no difference to the functioning of my custom board.

I did some more digging with the Ozone debugger. This is what I have discovered:

According to this: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fgpio.html the address of the GPIO IN Register that shows the status of all the GPIO pins at any point is 0x50000510. I am trying to toggle P0.18 on my hardware. This is what I see at that memory location within the Memory Window of Ozone with the relevant GPIO (P0.18) pulled low (so the LED turns on)

50000500 00 00 00 00 60 00 00 00 60 00 00 00 60 00 00 00

50000510 C0 01 20 00 60 00 04 00 60 00 04 00 60 00 04 00

And again with relevant GPIO (P0.18) pulled high (so the LED turns off):

50000500 00 00 00 00 60 00 04 00 60 00 04 00 60 00 04 00

50000510 C0 01 20 00 60 00 04 00 60 00 04 00 60 00 04 00

So I can’t quite make sense of the actual bytes that are changing and correlate that to the relevant GPIO. But at least it looks like the relevant registers are being updated.

And the bizarre thing is, I am now seeing the correct activity on the relevant GPIO pin!

However, if I stop debugging, and flash the custom board with the same firmware I was using during debugging, but don’t run the debugger, then I am not seeing any activity on the GPIO.

Any ideas why this might be occurring?

Regards,

Mike

RE: Issues with programming/operation of custom PCB with nRF52832

Kazi Afroza Sultana — Mon, 26 Sep 2022 07:22:02 GMT

Hello Mike,

The design looks ok. The decoupling capacitor are a bit from the SoC, this might have some deviation from the design in layout. However it's not critical problem, we guess.

You do not have DCDC in the design. But DK has. So you need to disable the DCDC in the application before programming the device.

CONFIG_BOARD_ENABLE_DCDC=n

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Mon, 26 Sep 2022 00:46:28 GMT

This is my code BTW:

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

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

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

/* The devicetree node identifier for the "led1" alias. */
#define LED_GRN_NODE DT_ALIAS(led1)

/*
 * 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_grn = GPIO_DT_SPEC_GET(LED_GRN_NODE, gpios);

void main(void)
{
	int ret;

	if (!device_is_ready(led_grn.port)) {
		return;
	}

	ret = gpio_pin_configure_dt(&led_grn, GPIO_OUTPUT_ACTIVE);
	if (ret < 0) {
		return;
	}

	while (1) {
		ret = gpio_pin_toggle_dt(&led_grn);
		if (ret < 0) {
			return;
		}
		
		k_msleep(SLEEP_TIME_MS);
	}
}

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Mon, 26 Sep 2022 00:45:45 GMT

OK, some more info.

Ran the debugger on my custom board. It seems to be running the code as expected, as I can see if running through the while loop. If I dive into the gpio_pin_toggle_dt(&led_grn) function, I can see it running a bunch of GPIO API's. Not sure how I can watch the GPIO register to confirm its toggling the status of the appropriate GPIO though.

But monitoring the physical pin with my scope, I'm not seeing any change in the state of the pin. I see the same outcome if I let the code run "free" without the debugger.

So, its like the GPIO isn't being configured for my custom board chip correctly. Not sure why though

Regards,

Mike

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Fri, 23 Sep 2022 06:37:41 GMT

Did some more work on this today:

1) Swapped out the 32MHz Xtal on my custom board with the 32MHz xtal off my DK and re-tested. The DK worked with the 32MHz xtal off my custom board but my custom board isn't working with the 32MHz xtal off the DK

2) Had a detailed look at the recommended layout as per the DK documentation. The only thing I've done differently that might be an issue is that I've not made the VSS connection to Pin 31 in the recommended way. But I can't see that preventing the chip from functioning at all.

I've got a 4 layer PCB with GND pours on the bottom layer, top layer and layer 2. I've also got a pour on layer 3 that is connected to VDD.

Screen shots of the layout around the chip are shown below:

Top Layer:

Layer 2 (GND Pour):

Layer 3 (VDD pour):

Bottom Layer (GND pour):

Regards,

Mike

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Fri, 23 Sep 2022 00:24:51 GMT

Hi Kazi,

Thanks for getting in touch. Answers to your questions:

1. Yes, I have the 32.768KHz crystal mounted. Its the ECS-.327-12.5-34B-C-TR from ECS with 18pF load capacitors

2. I'm using Visual Studio Code (V1.71.2) as my IDE, and am running V2.0.0 of NCS and v2022.9.179 of the nRF Connect extension for VSC.

3. I am using the nrf52dk_nrf52832.dts board file when I build my code.

4. I have not yet tested the radio on my board, as I can't even get a simple LED blinky code running on it as yet.

5. Yes, I can read the devices memory. I did a comparative test here, following this process:

(a) Programmed DK with a different version of code

(b) Programmed my device using the LED blinky code. Then read this back and saved as a file

(c) Disconnected my device and then read back the code in the DK. Checked this against the file in (b). I didn't do an exhaustive comparison, but I could see the files were different

(d) Programmed my DK with the same code I had programmed the device with in (b)

(e) Read back the file from my DK and compared this to the file I read back in (b). Again, I didn't do an exhaustive comparison, but it looked to me like they were the same file.

So, this seems to indicate that my device is actually being programmed, but for whatever reason its not actually running the code as expected.

I've disconnected all physical connections to my device apart from the crystals, the VDD/GND and SWDIO/SWDCLK signals and all the various PSU decoupling capacitors.

Regards,

Mike

RE: Issues with programming/operation of custom PCB with nRF52832

Kazi Afroza Sultana — Wed, 21 Sep 2022 21:47:29 GMT

Hello,

We would like to know the answers of following questions:

Do you have the 32.768kHz crystal mounted also?

What SDK are you using? NCS and the nRF5 SDK?

When you build the HEX file that you program to the custom board do you build for the DK or you build for a custom board file?

Have you tested the radio on a pre-production sample? It seems here is quite few RF components that can effect the performance significantly.

Are you able read the devices memory with nrfjprog or the programmer app from the nRF desktop app?

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: Issues with programming/operation of custom PCB with nRF52832

Mike Austin (LPI) — Wed, 21 Sep 2022 07:04:21 GMT

A bit of an update...

I've disconnected all my GPIO, so the chip basically isn't loaded up on any inputs apart from the I2C SCL/SDA. Everything else is free to do whatever it wants.

Flashing my LED Blinky code now appears to do nothing to any of the GPIO. And the unexpected behaviour on P0.05 only appears when I've got the custom board powered off an external 3V supply. Current is still sitting around the 7.5mA level.