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/*
# WS2812 Library for libopencm3
Please mind these restrictions:
- Only usable with libopencm3
- Newer versions of libopencm3 may be not compatibel (libopencm3 api is not stable yet)
- Just usable with a clock frequency of 80 MHz
- You have to setup the clock and gpio yourself
*/
#include "ws2812.h"
#define NUMBER_NOPS_RESET 1080 // > 50 µs --> 60 µs (to be sure) = 4320 cycles @ 72 MHz = 1080 nops
#define NUMBER_NOPS_LONG 16 // 0.9 µs = 64.8 cycles @ 72 MHz = 16.2 nops --> 11.1 ns timing error
#define NUMBER_NOPS_SHORT 6 // 0.35 µs = 25.2 cycles @ 72 MHz = 6.3 nops --> 16.7 ns timing error
void ws2812_init(ws2812_init_typedef *control_struct, uint32_t port, uint16_t pin, uint32_t array_length, uint32_t matrix_width)
{
control_struct->gpio_port = port;
control_struct->gpio_pin = pin;
control_struct->array_length = array_length;
control_struct->matrix_width = matrix_width;
control_struct->led_array = malloc(sizeof(uint8_t[array_length][3]));
ws2812_clear_buffer(control_struct);
ws2812_send_reset(control_struct);
}
void ws2812_send_reset(ws2812_init_typedef *control_struct)
{
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_RESET; i++) {
__asm__("nop");
}
}
void ws2812_send_zero(ws2812_init_typedef *control_struct)
{
gpio_set(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_SHORT; i++) {
__asm__("nop");
}
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_LONG; i++) {
__asm__("nop");
}
}
void ws2812_send_one(ws2812_init_typedef *control_struct)
{
gpio_set(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_LONG; i++) {
__asm__("nop");
}
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_SHORT; i++) {
__asm__("nop");
}
}
void ws2812_send_byte(ws2812_init_typedef *control_struct, uint8_t data)
{
for (int i=7; i>=0; i--){
if ( (data >> i) & 0x01 ){
ws2812_send_one(control_struct);
}
else {
ws2812_send_zero(control_struct);
}
}
}
void ws2812_send_led(ws2812_init_typedef *control_struct, uint8_t red, uint8_t green, uint8_t blue)
{
ws2812_send_byte(control_struct, green);
ws2812_send_byte(control_struct, red);
ws2812_send_byte(control_struct, blue);
}
void ws2812_write_leds(ws2812_init_typedef *control_struct)
{
for(uint32_t i=0; i<(control_struct->array_length); i++){
ws2812_send_led(
control_struct,
control_struct->led_array[i][0], // red
control_struct->led_array[i][1], // green
control_struct->led_array[i][2] // blue
);
}
ws2812_send_reset(control_struct);
}
void ws2812_set_array_led(ws2812_init_typedef *control_struct, uint32_t index, uint8_t red, uint8_t green, uint8_t blue)
{
control_struct->led_array[index][0] = red;
control_struct->led_array[index][1] = green;
control_struct->led_array[index][2] = blue;
}
void ws2812_set_matrix_led(ws2812_init_typedef *control_struct, uint32_t x, uint32_t y, uint8_t red, uint8_t green, uint8_t blue)
{
ws2812_set_array_led(control_struct, (x + y * (control_struct->matrix_width)), red, green, blue);
}
void ws2812_clear_buffer(ws2812_init_typedef *control_struct)
{
for (uint32_t i=0; i<control_struct->array_length; i++){
ws2812_set_array_led(control_struct, i, 0, 0, 0);
}
}
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