Adding a peripheral to a project using BLE

[GunnerDx]

I have a project that runs I2C to collect data from a pressure sensor and I have a different project that sends arrays of data over Bluetooth and they both work perfectly fine. Now I'm trying to add the I2C part to the Bluetooth project. I added I2C to the .overlay file and the prj.conf file however the function "device_get_binding" still returns a NULL pointer for I2C.

Can someone please tell me what am I missing or what am I doing wrong ?

Thank you in advance.

[Øivind]

Hi,

Could I see the .overlay file, prj.conf file, and the code where you call the device_get_binding() function?

[GunnerDx]

Hello,

I the bluetooth project I'm working on is the 'peripheral_uart' example to which I want to add the I2C code and send the data via Bluetooth.

Here is the code in the .overlay file :

 {
	soc {

                &i2c1 {
                      status = "okay";
                      compatible = "nordic,nrf-twim";
                      label = "I2C_1";
                      sda-pin = <5>;
                      scl-pin = <4>;
                      clock-frequency = <400000>; 
              };
		/* Add a flash controller which has the compatible
		 * 'zephyr,sim-flash'. This will ensure that the flash
		 * simulator can use it. None of the other properties in this
		 * node is used for anything.
		 */
		nordic_ram_flash_controller: nordic_ram-flash-controller@0 {
			compatible = "zephyr,sim-flash";
			reg = <0x00000000 DT_SIZE_K(40)>;
			#address-cells = <1>;
			#size-cells = <1>;
			erase-value = <0xff>;
			label = "nordic_ram_flash_flash_controller";

			/* This node label must match that used in the flash
			 * simulator.
			 */
			flash_sim0: flash_sim@0 {
				status = "okay";
				compatible = "soc-nv-flash";
				label = "simulated_flash";
				erase-block-size = <4096>;
				write-block-size = <4>;
				reg = <0x00000000 DT_SIZE_K(256)>;

				partitions {
					compatible = "fixed-partitions";
					#address-cells = <1>;
					#size-cells = <1>;

					/* This partition must be defined for
					 * MCUboot to find the partition ID
					 * of the primary slot for image 1,
					 * which is stored in this partition.
					 */
					slot2_partition: partition@0 {
						label = "image-2";
						reg = <0x00000000 0x00000A000>;
					};
				};
			};
		};
	};
};

Here is the prj.conf :

# Enable the UART driver
CONFIG_UART_ASYNC_API=y
CONFIG_NRFX_UARTE0=y
CONFIG_SERIAL=y

CONFIG_GPIO=y

# Make sure printk is printing to the UART console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

# Stacks and heaps
CONFIG_MAIN_STACK_SIZE=16384
CONFIG_HEAP_MEM_POOL_SIZE=16384

# I2C
CONFIG_I2C=y
CONFIG_NRFX_TWIM=y
CONFIG_NRFX_TWIM1=y

# Rebooot
CONFIG_REBOOT=n
CONFIG_RESET_ON_FATAL_ERROR=n

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Nordic_UART_Service"
CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=1

# Enable the NUS service
CONFIG_BT_NUS=y

# Enable bonding
CONFIG_BT_SETTINGS=y
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y
CONFIG_NVS=y
CONFIG_SETTINGS=y

# Enable DK LED and Buttons library
CONFIG_DK_LIBRARY=y

# This example requires more workqueue stack
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

# Config logger
CONFIG_LOG=y
CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n

CONFIG_ASSERT=y

I am calling the device_get_binding() function in main() :

    const struct device *i2c_dev;

    i2c_dev = device_get_binding("I2C_1");
    
    if (i2c_dev==NULL) printk("I2C_Driver NOT Found\n");

    else  printk("I2C_Driver Found\n");

I am probably doing something wrong

[Øivind]

In your overlay file, try moving the " &i2c1 {}; " outside the other brackets:

{
    soc {
    
        ...
    
    };
};

&i2c1 {
    ...
};

[GunnerDx]

I tried that but it didn't work. I feel like the changes I made in the overlay file are not being taken into account. Is there something that needs to be done after modifying the overlay file ? Because I just save it and rebuild the solution everytime. Maybe that is not enough

[Øivind]

Ah, if you are using SES, you need to click Project->Run CMake for any changes in .overlays, prj.conf etc. to be applied.

[GunnerDx]

Yes that was it. It worked, thank you so much. I had no idea I have to do that manually, I thought it was done automatically when you save.

Thanks again.

[Øivind]

Great to hear! Yes, it's a quirk of how projects are handled with SES. No manual update is required when using the VS Code extension for nRF Connect or when using the command line.