blink_loop.c File Reference

Blinks one or more WS2812 devices using a more memory efficient method than the blink_array.c example. More...

#include <avr/io.h>
#include <util/delay.h>
#include <ws2812.h>

Include dependency graph for blink_loop.c:

Go to the source code of this file.

Macros
#define	N_LEDS   8
	Number of LEDs on your WS2812 device(s)
#define	DATA_PINS_PORT   PORTB
	Port register used to communicate with the WS2812 device(s)
#define	DATA_PINS_DDR   DDRB
	Data direction register of the pin(s) used to communicate with the WS2812 device(s)
#define	DATA_PINS   {PB0, PB1}
	Pin(s) used to communicate with the WS2812 device(s)
#define	RESET_TIME   50
	Reset time in microseconds (50us recommended by datasheet)
#define	COLOR_ORDER   grb
	Color order of your WS2812 LEDs (Typically grb or rgb)

Functions
int	main ()

Variables
ws2812_rgb	white = {255,255,255}
ws2812_rgb	black = {0, 0 ,0}

Detailed Description

Blinks one or more WS2812 devices using a more memory efficient method than the blink_array.c example.

Author

Patrick Pedersen

Date

2021-04-09

The following example showcases how the Tiny-WS2812 library can be used on AVR platforms to blink an entire WS2812 device in white. Unlike the other blink example, we do not allocate a memory expensive array for every single LED here, but instead loop the transmission of a single RGB value until all WS2812 LEDs have been set.

The advantage of this method is that we can save allot of memory, the disadvantage is that this method is more prone to programming mistakes.

Note

Please ensure that the WS2812_TARGET_PLATFORM_AVR macro is defined during compilation. This can either be done by specifying -DWS2812_TARGET_PLATFORM_AVR in the build flags, or by uncommenting the define WS2812_TARGET_PLATFORM_AVR directive below.

Definition in file blink_loop.c.

Function Documentation

main()

int main

(

)

Blinks one or more WS2812 device(s)

Definition at line 63 of file blink_loop.c.

{
        uint8_t pins[] = DATA_PINS; // Data pins
        ws2812_cfg cfg;             // Device configurationn
        ws2812 ws2812_dev;          // Device struct
 
        // Configure the WS2812 device struct
        cfg.port = &DATA_PINS_PORT;
        cfg.ddr = &DATA_PINS_DDR;
        cfg.pins = pins;
        cfg.n_dev = sizeof(pins);     // Number of devices driven by this struct
        cfg.rst_time_us = RESET_TIME;
        cfg.order = grb;
        
        if (ws2812_config(&ws2812_dev, &cfg) != 0) {
                // HANDLE ERROR...
                void;
        };
 
        // Blink device
        while (1) {
                // Prepare to transmit data
                ws2812_prep_tx(&ws2812_dev);
 
                // Program all LEDs to white
                for (unsigned int i = 0; i < N_LEDS; i++) {
                        ws2812_tx(&ws2812_dev, &white, sizeof(white)/sizeof(ws2812_rgb));
                        // THIS LOOP NEEDS TO RUN UNINTERRUPTED!
                }
                
                // Close transmission
                ws2812_close_tx(&ws2812_dev);
 
                // Wait 500ms
                _delay_ms(500);
 
                // Prepare to transmit data
                ws2812_prep_tx(&ws2812_dev);
 
                // Program all LEDs to black (off)
                for (unsigned int i = 0; i < N_LEDS; i++) {
                        ws2812_tx(&ws2812_dev, &black, sizeof(black)/sizeof(ws2812_rgb));
                        // THIS LOOP NEEDS TO RUN UNINTERRUPTED!
                }
                
                // Close transmission
                ws2812_close_tx(&ws2812_dev);
 
                // Wait 500ms
                _delay_ms(500);
        }
 
        return 0;
}