1 files changed, 125 insertions, 0 deletions
diff --git a/libraries/ws2812.c b/libraries/ws2812.c
new file mode 100644
index 0000000..41d4fb5
--- /dev/null
+++ b/libraries/ws2812.c
@@ -0,0 +1,125 @@
+
+
+/*
+
+# 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);
+	}
+}