Controlling RGB Led from imx6sl connected to pwm pin

[sandeepajesh]

Hi Team

I am working on Free-scale imx6sl and I have to control NeoPixel Digital RGB led which will be connected to it over pwm.

From documents i can see that there are 4 pwm pins in imx6sl.

PWM-1

PWM-2

PWM-3

PWM-4

Can someone please suggest how can i proceed here.Is there any existent driver for it ?

RGB Led Details:-

• Maximum 5V @ 60mA draw per 1.3" strip segment (all LEDs on full brightness)
• 5VDC power requirement (do not exceed 6VDC) - no polarity protection
• The frequency of PWM FPWM --- 1.2 --- KHZ ---

Regards

Sandeep S

[CarlosCasillas · Accepted solution]

Hi Sandeep,

If the pins are used by other modules, it will be required enabling the pins as PWM functionality on the Device Tree.

Additionally, you could check the following links, maybe some information would be useful:

linux/pwm – Gateworks

Linux/drivers/pwm/pwm-imx.c - Linux Cross Reference - Free Electrons http://lxr.free-electrons.com/source/drivers/pwm/pwm-imx.c

[U-Boot] [PATCH v3 3/6] pwm, imx6: add support for pwm modul on imx6

And the following document for reference in case of modifying the Device Tree:

Basic Device Tree for the Udoo Board

The information above is regarding software modifications to get PWM signals on the pins. Regarding hardware, it will be required adding a buffer between the i.MX pins and the LEDs, because i.MX pins have limited current/voltage capability, and LED arrays used to have a controller on the middle, so, please take a look on that.

Hope this will be useful for you.
Best regards!
/Carlos
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[sandeepajesh]

Hi Carlos

Thanks for the suggestion.

Below are the links of the LED controller and the LED from adafruit, I am planning to put a VOLTAGE Level Translator to convert the 3.3V of GPIO/PWM line of iMX6SL to 5V as required by LED tape.

Can you guide me here, I need to send a 24bit data from the iMX6 to LED tape to control the RGB pattern on LED. I am planning to use the EPDC_SDCE2/I2C3_SCL/PWM1OUT  line of iMX6 to do this job. Please comment your suggestion.

Led :-

https://cdn-shop.adafruit.com/product-files/1138/SK6812+LED+datasheet+.pdf

Controller:-

https://www.adafruit.com/product/2964

Regards

Sandeep S

[sandeepajesh]

Thanks Carlos,Very helpful information. I am going through it

Currently all 4 pins are free in our design.One quick question

Can PWM pin output  5v signal level?

Regards

Sandeep S