firmware-fret: ws2812 driving

* Bitbanged/fragile ws2812 driver
* Hooked up to the register
* Python tester to make pretty colors

firmware-fret/fret-tester.py

@@ -0,0 +1,73 @@
+from periphery import *
+
+i = I2C("/dev/i2c-0")
+
+I2C_ADDRESS = 0x25
+
+def process_key(key, size):
+	if type(key) is int:
+		start = key
+		length = 1
+	else:
+		slice_start, slice_stop, slice_step = key.indices(size)
+		if slice_step != 1:
+			raise AttributeError("Can't have non 1 step.")
+
+		start = slice_start
+		length = slice_stop - slice_start
+	return start, length
+
+class FretRegisters(object):
+	def __getitem__(self, key):
+		start, length = process_key(key, 256)
+
+		msg = [
+			I2C.Message([start, 0x00]),
+			I2C.Message([0x00] * length, read=True)
+		];
+
+		i.transfer(I2C_ADDRESS, msg);
+
+		if type(key) is int:
+			return msg[1].data[0];
+		else:
+			return msg[1].data;
+
+	def __setitem__(self, key, value):
+		start, length = process_key(key, 256)
+		if type(key) is int:
+			value = [value]
+		else:
+			value = list(value)
+
+		i.transfer(I2C_ADDRESS, [I2C.Message([start, 0x00] + value)]);
+
+	def __repr__(self):
+		return "FretRegisters"+repr(f[:])
+
+f=FretRegisters()
+
+def dynamic_led_test():
+	def rotate(l,n):
+		return l[n:] + l[:n]
+
+	colors = (
+		[[255-x,0,x] for x in range(255)] +
+		[[0,x,255-x] for x in range(255)] +
+		[[x,255-x,0] for x in range(255)]
+	)
+	colors=colors[::6] #faster
+	#colors = [[b,b,b] for r,g,b in colors] #white glow
+
+	while True:
+		for j in range(len(colors)):
+			c=rotate(colors,j)[::len(colors)//6]
+			#for g in range(20*2//10):
+				##what if we had more frets(20x slower), was doing touch(2x slower), but increased the i2c speed(10x faster) too
+			f[0x80:]=sum(c,[])+[0x00]
+			#for g in range(20*2//10):
+				##blink test to show the fps
+				#f[0x80:]=[0x00]*6*3+[0x00]
+
+if __name__=="__main__":
+	dynamic_led_test()

firmware-fret/main.c

@@ -36,6 +36,7 @@
 #include <stdlib.h>
 #include "timer.c"
 #include "i2c_slave.c"
+#include "ws2812.c"
 
 static void gpio_setup(void)
 {
@@ -47,6 +48,9 @@ static void gpio_setup(void)
 	rcc_periph_clock_enable(RCC_GPIOC);
 	gpio_mode_setup(GPIOC, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO6 | GPIO7 | GPIO8 | GPIO9);
 	gpio_clear(GPIOC, GPIO6 | GPIO7 | GPIO8 | GPIO9);
+
+	rcc_periph_clock_enable(RCC_GPIOC);
+	gpio_mode_setup(GPIOC, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO12);
 }
 
 int _write(int file, char *ptr, int len)
@@ -87,19 +91,30 @@ void usart_setup(void)
 }
 
 unsigned char registers[0x100];
+/*
+ * Map:
+ * 0x00 : CHIP_ID "0x25"
+ * 0x80-0x91 : RGB LEDs values
+ * 0x92 : Commit the RGB LEDs (write anything)
+ *
+ */
+uint8_t *ws2812_colors = registers + 0X80;
 
 #define CHIP_ID 0x25
 
-void registers_init() {
-	registers[0] = CHIP_ID;
-
+void registers_init(void) {
+	registers[0x00] = CHIP_ID;
 }
 
 void registers_read_callback(uint16_t address) {
 	//printf("r 0x%04x==0x%02x\n", address, registers[address]);
 }
 void registers_write_callback(uint16_t address) {
-	printf("w 0x%04x:0x%02x\n", address, registers[address]);
+// 	printf("w 0x%04x:0x%02x\n", address, registers[address]);
+	if (address == 0x92) {
+// 		printf("set leds");
+		ws2812_sendarray(ws2812_colors,6*3);
+	}
 }
 
 int main(void)
@@ -108,6 +123,7 @@ int main(void)
 	systick_setup();
 	usart_setup();
 	gpio_setup();
+	registers_init();
 
 	gpio_set LED_GREEN;
 	printf("\n\nGuitar Fret Discovery Board\n");
@@ -117,6 +133,8 @@ int main(void)
 
 	i2c_setup();
 
+	ws2812_sendarray(ws2812_colors,6*3);
+
 	while(1){
 		printf(".");
 		msleep(100);

firmware-fret/ws2812.c

@@ -0,0 +1,40 @@
+//Bitbanging ws2812 implementation
+//Requires disabled interrupts to run
+//Dependent on system clock being 48MHz
+//Here be dragons, don't touch
+
+#include <libopencm3/cm3/cortex.h>
+
+__attribute__((optimize("unroll-loops")))
+__attribute__((always_inline))
+inline void ws2812_write_byte(uint8_t byte) {
+	for(int j = 7; j >= 0; j--)
+	{
+		bool bit = (byte & (1 << j)) == 0;
+		gpio_set(GPIOC,GPIO12);
+		GPIOC_BSRR = 1 << 12;
+		if(bit)
+			GPIOC_BSRR = 1 << 12 << 16;
+		__asm__("nop");
+		__asm__("nop");
+		__asm__("nop");
+		__asm__("nop");
+		__asm__("nop");
+		__asm__("nop");
+		GPIOC_BSRR = 1 << 12 << 16;
+	}
+}
+
+__attribute__((optimize("unroll-loops")))
+void ws2812_sendarray(uint8_t *buf, uint16_t size) {
+	for(volatile int i = 0; i < 100; i++);
+
+	cm_disable_interrupts();
+	for(uint16_t i = 0; i < size; i+=3)
+	{
+		ws2812_write_byte(buf[i+1]);
+		ws2812_write_byte(buf[i+0]);
+		ws2812_write_byte(buf[i+2]);
+	}
+	cm_enable_interrupts();
+}