I2c pin connections on nrf9160-DK

RE: I2c pin connections on nrf9160-DK

Carl Richard — Thu, 14 Jan 2021 12:38:49 GMT

Good to hear!

I guess UART1 or some other _1-peripheral is active somehow.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Thu, 14 Jan 2021 12:18:44 GMT

Many thx Carl.

Switching over to I2C2 fixed it. Sensible values coming back from the sensor.

Regards, Paul

RE: I2c pin connections on nrf9160-DK

Carl Richard — Thu, 14 Jan 2021 11:46:09 GMT

Hi again!

The sensor is appearently not communicating properly with the nRF9160. Are you able to probe the pin P0.10 and P0.11 to see if there are any activity at all? If no activity, could you try using I2C_2 instead? There may be some interference with UART_1. In addition, could you have a look at what Jan Tore mentions in this comment about the BME280 on nRF9160?

I2C can access any of the GPIOs to that should not be an issue. You can read more about available GPIO on the DK here.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Wed, 13 Jan 2021 18:28:26 GMT

Thx Carl,

OK. I checked the config against that example, also made sure that the connections were OK, including setting VDD to 3.3v. I checked at the datasheets for BME280 (its address is 0x76) and tried a second module in case the first one was not working.

I wanted to verify the I2C_1 is accessible on PO.10 and PO.11 but could not find that in the user guide.

So I'm stuck now.

I'd like to be able to look at what's happening during the call to device_get_binding() but I don't understand enough about all the driver magic that relies on.

Regards

RE: I2c pin connections on nrf9160-DK

Carl Richard — Wed, 13 Jan 2021 11:36:50 GMT

I see. It should not be necessary to change the prj.conf.

Are your sure that the correct adress for the sensor is used in the overlay? If you're using a different board for the BME280 than the one in the tutorial the address may be different aswell. I believe the address is available in the documentation of the sensor board, but if it isn't you could use this unofficial I2C scanner sample.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Wed, 13 Jan 2021 10:34:33 GMT

Thx Carl,

Just changing the overlay did not fix it.

in prj.conf would this still be correct?

```

CONFIG_SENSOR=y

CONFIG_BME280=y

CONFIG_I2C_1=y

CONFIG_I2C=y

```

Regards.

RE: I2c pin connections on nrf9160-DK

Carl Richard — Wed, 13 Jan 2021 07:22:04 GMT

Hi again!

Could you try to use P0.10 and P0.11 instead? These should work just as well for I2C.

P0.30 and P0.31 are used for I2C communication with the I/O expander of the DK and are thus not available for use when that is enabled. Apologies for not informing you earlier about this. I was not aware of it myself.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Tue, 12 Jan 2021 15:49:42 GMT

OK. We have and error initialising the I2C device:

```

const struct device *dev = device_get_binding(BME280_LABEL);

produces dev == NULL

```

I have downloaded and searched through various documents to check the pin numbering for I2C but found nothing so connections are as above (PO.30 and PO.31).

Are any other hardware links etc needed?

Regards

RE: I2c pin connections on nrf9160-DK

Carl Richard — Tue, 12 Jan 2021 14:08:23 GMT

Good to hear that it helped you solve the issue! I believe using SPI only will be a manner of changing prj.conf and the overlay, yes.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Tue, 12 Jan 2021 13:46:07 GMT

Many thx Carl. That was the issue. I should know better than to trust file system viewers on MacOS (and other platforms). Now to hook it up and fully test...

Meanwhile, I was looking for an SPI example (bme280 does both). I suppose this would just be an overlay change.

Regards, Paul

RE: I2c pin connections on nrf9160-DK

Carl Richard — Tue, 12 Jan 2021 11:42:12 GMT

The build fails here as well.

I see that the nRF9160 overlay you're using is named "(...).overlay.txt". Could you try to remove the ".txt" part? That works for me.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Tue, 12 Jan 2021 10:48:37 GMT

ncs is 3.6.0

zip of zephyr/drivers/sensor/bme280 is attached

devzone.nordicsemi.com/.../bme280.zip

RE: I2c pin connections on nrf9160-DK

Carl Richard — Tue, 12 Jan 2021 10:11:20 GMT

Hi again.

The overlay should be in the correct place. What version of NCS are you using?

Please send me a compressed file with the project, so that I could test it here.

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Tue, 12 Jan 2021 09:53:47 GMT

Sorry I forgot to say. On command line:

west build -b nrf9160dk_nrf9160ns -p

Regards.

RE: I2c pin connections on nrf9160-DK

Carl Richard — Tue, 12 Jan 2021 09:16:00 GMT

I see. How are you building the sample? When using SES the project must be reloaded before the changes apply. When using commandline tools the application should be built as "pristine".

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Tue, 12 Jan 2021 08:47:44 GMT

Thx for the clarification Carl.

I checked the two files and all is as above, however, I still get the same error.

Your devicetree has no enabled nodes with compatible "bosch,bme280"

I wonder if I have the .overlay file in the right place?

```

..ncs/zephyr/samples/sensor/bme280

boards

nrf9160dk_nrf9160ns.overlay

build

CMakeLists.txt

Kconfig

prj.conf

src

main.c

```

BTW. I also checked the .yaml file and put nrf9160dk_nrf9160ns in the platform_allow field.

RE: I2c pin connections on nrf9160-DK

Carl Richard — Tue, 12 Jan 2021 07:46:24 GMT

Hi again!

First, you are correct that the DK has two chips on it, but as it is a nRF9160 development kit all GPIO are routed to the SiP. You can read more about available GPIO and the nRF52840's role on the board in the Hardware description.

As shown in the tutorial I linked the SDA and SCL pins must be specified in the overlay aswell. Furthermore, I recommend using I2C1 as I2C0 can't coexist with UART0. UART0 is by default used for serial logging from the DK. When using the following nrf9160dk_nrf9160ns.overlay the sample built successfully for me:

&i2c1 {
    compatible = "nordic,nrf-twim";
	status = "okay";
	sda-pin = < 30 >;
	scl-pin = < 31 >;
    clock-frequency = <I2C_BITRATE_STANDARD>;  
	
	/* The I2C address could be one of two, here 0x76 is assumed */
	bme280@76 {
		compatible = "bosch,bme280";
		reg = <0x76>;
		label = "BME280";
	};
};

&uart1 {
    status = "disabled";
};

I used the following prj.conf:

CONFIG_SENSOR=y
CONFIG_BME280=y
CONFIG_I2C_1=y
CONFIG_I2C=y

Best regards,
Carl Richard

RE: I2c pin connections on nrf9160-DK

paul_tanner — Mon, 11 Jan 2021 15:28:24 GMT

Thx Carl

I found ../ncs/zephyr/samples/sensor/bme280 in the SDK.

Then added nrf9160dk_nrf9160ns.overlay in the boards folder:

```

&i2c0 {
bme280@77 {
compatible = "bosch,bme280";
reg = <0x77>;
label = "BME280";
};
};

```

When trying to build this I get

```

error: #error Your devicetree has no enabled nodes with compatible "bosch,bme280"

```

I don't understand how to check that the following is valid for nrf9160dk

```

BME280	Board
SCL	P0.31
SDA	P0.30
GND	GND
VIN	VDD

```

Regards.

PS. Being that the DK has two Nordic chips on it, please note that I want to do this with the 9160 without using the nRF52840. The DK board has pins labelled PO.30 and PO.31 but it's not clear how these are connected.

RE: I2c pin connections on nrf9160-DK

Carl Richard — Mon, 11 Jan 2021 08:58:43 GMT

Hi, Paul!

In chapter 1.2 of the nRF Connect SDK tutorial - Part 3, simon explains how the BME280 can be used with the nRF9160. I suggest trying out his approach.

Please reach out if you face any difficulities!

Best regards,
Carl Richard