Beginner needing help with basic structure and pwm

[jmguk41]

I am a complete beginner, working through the tutorials and trying not to ask basic questions. However, I am up against a customer time limit and need some help. I am trying to create a program similar to nrf Blinky and soft LED. I need remote on/off and a 0 to 100% control of a 1KHz pwm signal that I can select on an app, and the device will follow. Think of as remote dimming control. I'm using the Murata WSM-BL241-ADA-008 MBN52832 and laid out my pcb to match the Muarata dev board connections. I've downloaded S132 and the Blinky example to my design and the board is alive and functioning as expected. So basically now I need some guidance on where to start adding advertising, the service, the raw data etc for pwm functionality to my version of Blinky. Thank you!

[Bjørn Kvaale]

Might be useful to start with this custom service tutorial.

[jmguk41]

Thanks for the link. I did see that earlier and have been working my way through it however I am getting an error when trying to compile the code.

L6050U: The code size of this image (34532 bytes) exceeds the maximum allowed for this version of the linker.

Apparently I'm using MDK-Lite which I downloaded via a link in the SDK.

[Sigurd]

Here is an example based on ble_app_uart + PWM driver for SDK 15. You can control the PWM duty cycle, by sending values in the range from 0 to 100, either using nRF Toolbox or nRF Connect. A 1KHz PWM is generated at pin 20 (led 4). Note that this is just a very quick prototype done in 10min, for an end-product you might want to create your own custom service for this.

Extract the .rar file in the ble_peripheral folder.

ble_app_uart_pwm_driver_1KHz.rar

EDIT:

Here is the custom service tutorial + PWM Driver. Write to the custom characteristic to adjust the PWM duty cycle.

ble_app_template_pwm_driver.rar

[jmguk41]

Thanks! This works fantastic!

I changed the pin that the PWM signal is present on and my product dims almost perfectly!

Couple of questions: Sending a value of 100 turns off the output, not sure if this could be changed to a 100% duty cycle?

EDIT: FIXED THIS BY CHANGING

if(duty_cycle >= 1000)
    {
        seq_values->channel_0 = 1000;
    }

TO

if(duty_cycle > 1000)
    {
        seq_values->channel_0 = 0;
    }

How do I change the advertising and connected LED's to different pins? The pwm pin and advertising led share the same io now and I need to move or delete the led function.

If I want to run an additional service, a custom one, do I need to write that in another file? I want to read the devices temperature, hit a button on the app and send the pwm to 0, hit again and toggle back the original pwm vale. That may be an app side job though.

I tried incorporating the custom service tutorial into the pwm example. It did not work very well. 

Id like to thank you all for helping me learn this stuff and being patient with me while I fumble my way around.

[Bjørn Kvaale]

Take a look how the ble_blinky application does this in the ble_peripheral folder of sdk 15. The LEDs are defined in main.c:

#define ADVERTISING_LED BSP_BOARD_LED_0 /**< Is on when device is advertising. */
#define CONNECTED_LED BSP_BOARD_LED_1 /**< Is on when device has connected. */

BSP_BOARD_LED_0 & BSP_BOARD_LED_1 are defined in boards.h. I would try to understand the code & take a look at the infocenter documentation to find out how this simple example works & how the LEDs are defined.

Good luck with future development!

[Chukwuemeka]

Hi Sigurd

I working on dimming two different LED strings independently (one at time) using nRF52834 SDK15. The idea is to use a high or low signal from GPIO to enable/disable a switch to one of the LED strings, and then dim the LED string that is enabled.

I have modified the ble_app_template you provided, and its working for a fixed LED string. My question is how do I modify the custom BLE service in order that I can set/clear two GPIOs before I send the PWM duty for dimming?

Thanks

[Bjørn Kvaale]

Could you please open a new devzone case?