Simple PWM example

RE: Simple PWM example

Stefano1984 — Wed, 17 Apr 2024 13:04:44 GMT

Thank you very much Andreas.

I think I will raise a new case.

RE: Simple PWM example

AHaug — Tue, 16 Apr 2024 12:04:25 GMT

Hi,

Unfortunately I do not have a solution for the I2C issues you're observing unless it is explained by the lesson I posted in my previous reply. If you want you could raise a new case for that since it is a different topic than the generic PWM topic of this cases original question, but I will look into your this topic during this week if you want to wait a bit for a reply.

Kind regards,
Andreas

RE: Simple PWM example

Stefano1984 — Tue, 16 Apr 2024 08:29:27 GMT

Hi Andreas,

do you have a solution to my problem?
Thank you
Best regards

RE: Simple PWM example

rajeev — Mon, 15 Apr 2024 15:21:15 GMT

hmm then this is concerning. Lemme try on my end and see what works. Else. hopefully Nordic tech team can suggest a solution.

RE: Simple PWM example

Stefano1984 — Mon, 15 Apr 2024 08:38:17 GMT

Hi,

Thanks for the reply but it still gives me the same error:

#define I2C_BITRATE_10KHZ 10000
#define I2C_BITRATE_STANDARD	100000	/* 100 Kbit/s */
#define I2C_BITRATE_FAST	400000	/* 400 Kbit/s */
#define I2C_BITRATE_FAST_PLUS	1000000 /* 1 Mbit/s */
#define I2C_BITRATE_HIGH	3400000	/* 3.4 Mbit/s */
#define I2C_BITRATE_ULTRA	5000000 /* 5 Mbit/s */

&i2c0 {
	status = "okay";
	pinctrl-0 = <&i2c0_default>;
	pinctrl-names = "default";
	clock-frequency = <I2C_BITRATE_10KHZ>;
};

static assertion failed: "Wrong I2C 0 frequency setting in dts"

Do you have any other suggestions?
Thank you.

RE: Simple PWM example

rajeev — Fri, 12 Apr 2024 16:36:27 GMT

Maybe try setting in i2c.h the following

#define I2C_BITRATE_10KHZ 10000 //your custom freq value

Then set

&i2c0 {
status = "okay";
pinctrl-0 = <&i2c0_default>;
pinctrl-names = "default";
clock-frequency = <I2C_BITRATE_10KHZ>;
};

See if that helps incase the device tree and I2C driver is only able to set frequency values defined in the i2c.h which zephyr looks for.

RE: Simple PWM example

Stefano1984 — Thu, 11 Apr 2024 09:54:59 GMT

HI,
I didn't understand how this solves my problem.
I2C_BITRATE_FAST corresponds to a frequency of 400 Kbit/s as specified in the i2c.h file:

#define I2C_BITRATE_STANDARD	100000	/* 100 Kbit/s */
#define I2C_BITRATE_FAST	400000	/* 400 Kbit/s */        <--------
#define I2C_BITRATE_FAST_PLUS	1000000 /* 1 Mbit/s */
#define I2C_BITRATE_HIGH	3400000	/* 3.4 Mbit/s */
#define I2C_BITRATE_ULTRA	5000000 /* 5 Mbit/s */

I need to go at a slower speed. I need a speed of 10 Kbit/s.

With nRF SDK I was able to do this by setting "frequency = 0x00290000UL".

void ext_twi_init(void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = EXT_SCL_PIN,
       .sda                = EXT_SDA_PIN,
       .frequency          = 0x00290000UL,      // = 10Kbit/s. <------------
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_ext_twi, &twi_config, NULL, NULL);
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_ext_twi);
}

How do I do the same thing using Zephyr?

Thank you

RE: Simple PWM example

AHaug — Fri, 05 Apr 2024 08:02:52 GMT

Hi,

TWI/I2C should be covered in lesson 6 in https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/

Kind regards,
Andreas

RE: Simple PWM example

rajeev — Thu, 04 Apr 2024 21:09:37 GMT

The i2c clock freq in zephyr needs to be set as such:

I2C_BITRATE_FAST etc....

&i2c1 {
	compatible = "nordic,nrf-twim";
	status = "okay";
	clock-frequency = <I2C_BITRATE_FAST>;

	pinctrl-0 = <&i2c1_default>;
	pinctrl-1 = <&i2c1_sleep>;
	pinctrl-names = "default", "sleep";
};

See all those frequency settings here
https://docs.zephyrproject.org/apidoc/latest/dt-bindings_2i2c_2i2c_8h.html

RE: Simple PWM example

Stefano1984 — Thu, 04 Apr 2024 16:05:03 GMT

Thank you,
these lessons are very useful.
However, I notice that there is a lesson missing that deals with the TWI module.
I was still able to communicate via the I2C BUS but I can't set the clock frequency. In particular I want to set a frequency of 10 kHz but I don't know how.

I tried to do like this:

&i2c0 {
	status = "okay";
	pinctrl-0 = <&i2c0_default>;
	pinctrl-names = "default";
	clock-frequency = <10000>;
};

But it gives me the following error:

C:/ncs/v2.6.0-rc2/zephyr/include/zephyr/toolchain/gcc.h:87:36: error: static assertion failed: "Wrong I2C 0 frequency setting in dts"

Can you help me?

Thank you

RE: Simple PWM example

AHaug — Wed, 03 Apr 2024 11:48:30 GMT

Hi,

In lesson 4 in https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/ we have a course showcasing how to use the PWM API in Zephyr through nRF Connect SDK. I recommend that you have a look at this. The solution to the hands on in this lesson can be seen in github.com/.../lesson4.

Kind regards,
Andreas