nrf52805 sample simple I2C

[nefen]

Is there any simple sample application utilizing i2c communications for nrf52805?

In Visual Studio Code with installed nrf connect SDK 2.0.0 doesn't show up any code sample.

Googling I came up with twi_scanner and a couple more of them, but I can't find them.

I found in the forum a tw_scanner.zip file, but still I face a hard time to wire up the configuration to make include files accessible (none of #include "boards.h", #include "app_util_platform.h", #include "app_error.h", #include "nrf_drv_twi.h") are found, although in a subdirectory it shows up that it is available for pca10040 and I have this DK and try to program an external board with nrf52805 (I managed to flash other bleutooth projects).

[Sigurd Hellesvik]

Hi

We actually have two different SDK-s, one new and one old. See the nRF Connect SDK and nRF5 SDK statement for more information on this.

For nRF Connect SDK, I recommend that you have a look at https://academy.nordicsemi.com/, where we have tutorials on getting started and some protocols, such as I2C.

Regards,
Sigurd Hellesvik

[nefen]

Dear Mr. Hellesvik,

I followed your suggestion and studied the tutorial.

Unfortunately, I can't still communicate with ADS7142,

In my board, SDA is on P0.16 and SCL on P0.12.

I added in the overlay file the following:

&pinctrl {
	i2c0_default: i2c0_default {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA, 0, 16)>,
				<NRF_PSEL(TWIM_SCL, 0, 12)>;
		};
	};

	i2c0_sleep: i2c0_sleep {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA, 0, 16)>,
				<NRF_PSEL(TWIM_SCL, 0, 12)>;
			low-power-enable;
		};
	};

	spi0_default: spi0_default {
		group1 {
			psels = <NRF_PSEL(SPIM_SCK, 0, 29)>,
				<NRF_PSEL(SPIM_MOSI, 0, 31)>,
				<NRF_PSEL(SPIM_MISO, 0, 30)>;
		};
	};
};
&i2c0 {
    pinctrl-0 = <&i2c0_default>;
    pinctrl-1 = <&i2c0_sleep>;
    pinctrl-names = "default", "sleep";
    ads7142: ads7142@18{
        status = "okay";
        compatible = "i2c-device";
        reg = < 0x18 >;
        label = "ADS7142";
    };
 };

Then I followed the tutorial and have the following in the main.c:

#define ADS7142_CHANNEL_CFG 0x24
#define ADS7142_OPMODE_CFG 0x1C

#define ADS7142_NODE DT_NODELABEL(ads7142)
...
void main(void){
    static  struct i2c_dt_spec dev_i2c = I2C_DT_SPEC_GET(ADS7142_NODE);
    uint8_t i2c_write_reg2[3]={0b00001000,ADS7142_CHANNEL_CFG,0x00};
    ...
    if (!device_is_ready(dev_i2c.bus)) {
		printk("I2C bus %s is not ready!\n\r",dev_i2c.bus->name);
		return;
	}
	...
	ret =i2c_write_dt(&dev_i2c,i2c_write_reg2, sizeof(i2c_write_reg2));
	...
	
	}

Off course I had enabled I2C in prj.conf, but I cannot manage to communicate properly.

TI manual for ADS7142 specifies the following sequence of bytes to write to a register:

I supposed that the first byte is automatically generated by the i2c_write_dt, but I had also tried to send all 4 bytes, again with no success.

 

Any idea?

[Sigurd Hellesvik]

Hi

It is helpful to know if the nRF chip sends data or just tries.

Try to connect a logic analyzer or oscilloscope to the I2C lines and see if you can detect signals when sending data

Regards,
Sigurd Hellesvik

[nefen]

Just a question.

I implemented logging and I saw the following error message:

[00:00:05.004,547] <err> i2c_nrfx_twi: Error 0x0BAE0001 occurred for message 0

How can I interpret this error?

[nefen]

Forget the last message, I managed out from nrfx_error.h that this is an address NACK, i.e. the slave address is not acknowledged.