add preliminary ws2812b uart app

src/app/ws2812b_uart/Makefile.inc

+loop ?= 1
+arch_drivers += ,stdin,neopixel

src/app/ws2812b_uart/main.cc

+#include "arch.h"
+#include "driver/neopixel.h"
+#include "driver/stdin.h"
+#include "driver/stdout.h"
+#include <util/delay.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/wdt.h>
+
+#define NUM_PIXELS 66
+
+Adafruit_NeoPixel np(NUM_PIXELS, GPIO::pb0, NEO_GRB+NEO_KHZ800);
+
+class Blinkencat {
+	public:
+		enum Mode : uint8_t {
+			OFF = 0,
+			RGBWHEEL_FAST,
+			RGBWHEEL_SLOW,
+			RGBFADE_FAST,
+			RGBFADE_SLOW,
+			BRIGHTRGBWHEEL_FAST,
+			BRIGHTRGBWHEEL_SLOW,
+			BRIGHTRGBFADE_FAST,
+			BRIGHTRGBFADE_SLOW,
+			COLD_WHITE,
+			STROBE,
+			COLOR_STROBE,
+			MODE_ENUM_MAX
+		};
+
+		Mode mode;
+
+		void setup(void);
+		void next_mode(void);
+		void idle(void);
+		void loop(void);
+
+		Blinkencat() : mode(RGBWHEEL_SLOW) {}
+};
+
+void Blinkencat::setup(void)
+{
+	np.setup();
+	gpio.input(GPIO::pb1, 0);
+	gpio.input(GPIO::pd3, 1);
+	gpio.enable_int(GPIO::pd3);
+
+	// One ADC conversion per four seconds
+	TCCR1A = 0;
+	TCCR1B = _BV(CS12) | _BV(CS10);
+
+	// Measure internal 1.1V bandgap using VCC as reference on each Timer 1 overflow
+	ADMUX = _BV(REFS0) | 0x0e;
+	ADCSRB = _BV(ADTS2) | _BV(ADTS1);
+	ADCSRA = _BV(ADEN) | _BV(ADATE) | _BV(ADPS2) | _BV(ADPS1);
+}
+
+void Blinkencat::idle(void)
+{
+	SMCR = _BV(SE);
+	asm("sleep");
+	SMCR = 0;
+}
+
+void Blinkencat::next_mode(void)
+{
+	mode = (Mode)((mode + 1) % MODE_ENUM_MAX);
+}
+
+void Blinkencat::loop(void)
+{
+	static uint16_t rgbwheel_offset = 0;
+	static uint16_t rgbfade_hsv = 0;
+	static uint8_t strobe_on = 0;
+
+	/*
+	// not working due to bad logic levels
+	if (gpio.read(GPIO::pb1)) {
+		// Arduino and WS2812 strip are connected in parallel with the battery,
+		// which will significantly confuse the charging circuit when the
+		// strip is active while charging. So we make sure that it isn't.
+		mode = OFF;
+	}
+	*/
+
+	switch (mode) {
+		case OFF:
+			// the mode may have been set by an ISR, which may in turn have
+			// been handled immediately after an np.show() call. So we must
+			// observe the 300us idle time mandated by WS2812.
+			_delay_ms(1);
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				np.setPixelColor(i, np.Color(0, 0, 0));
+			}
+			np.show();
+			idle();
+			break;
+		case RGBWHEEL_FAST:
+		case RGBWHEEL_SLOW:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				uint16_t hsv = (i * 252 + rgbwheel_offset) % 6553;
+				np.setPixelColor((NUM_PIXELS-1) - i, np.gamma32(np.ColorHSV(hsv * 10, 255, 127)));
+			}
+			rgbwheel_offset = (rgbwheel_offset + 10) % 6553;
+			np.show();
+			_delay_ms(1);
+			if (mode == RGBWHEEL_SLOW) {
+				_delay_ms(9);
+			}
+			break;
+		case RGBFADE_FAST:
+		case RGBFADE_SLOW:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				np.setPixelColor(i, np.ColorHSV(rgbfade_hsv * 10, 255, 63));
+			}
+			rgbfade_hsv = (rgbfade_hsv + 10) % 6553;
+			np.show();
+			_delay_ms(1);
+			if (mode == RGBFADE_SLOW) {
+				_delay_ms(99);
+			}
+			break;
+		case BRIGHTRGBWHEEL_FAST:
+		case BRIGHTRGBWHEEL_SLOW:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				uint16_t hsv = (i * 252 + rgbwheel_offset) % 6553;
+				np.setPixelColor((NUM_PIXELS-1) - i, np.gamma32(np.ColorHSV(hsv * 10)));
+			}
+			rgbwheel_offset = (rgbwheel_offset + 10) % 6553;
+			np.show();
+			_delay_ms(1);
+			if (mode == BRIGHTRGBWHEEL_SLOW) {
+				_delay_ms(9);
+			}
+			break;
+		case BRIGHTRGBFADE_FAST:
+		case BRIGHTRGBFADE_SLOW:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				np.setPixelColor(i, np.ColorHSV(rgbfade_hsv * 10));
+			}
+			rgbfade_hsv = (rgbfade_hsv + 10) % 6553;
+			np.show();
+			_delay_ms(1);
+			if (mode == BRIGHTRGBFADE_SLOW) {
+				_delay_ms(99);
+			}
+			break;
+		case COLD_WHITE:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				np.setPixelColor(i, np.Color(127, 127, 127));
+			}
+			np.show();
+			idle();
+			break;
+		case STROBE:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				np.setPixelColor(i, np.Color(strobe_on, strobe_on, strobe_on));
+			}
+			np.show();
+			strobe_on = 127 - strobe_on;
+			_delay_ms(40);
+			break;
+		case COLOR_STROBE:
+			for (uint16_t i = 0; i < NUM_PIXELS; i++) {
+				if (strobe_on) {
+					np.setPixelColor(i, np.ColorHSV(rgbfade_hsv * 10));
+				} else {
+					np.setPixelColor(i, np.Color(0, 0, 0));
+				}
+			}
+			rgbfade_hsv = (rgbfade_hsv + 50) % 6553;
+			np.show();
+			strobe_on = 127 - strobe_on;
+			_delay_ms(40);
+			break;
+	}
+}
+
+Blinkencat blinkencat;
+
+int main(void)
+{
+	arch.setup();
+	gpio.setup();
+	kout.setup();
+	kin.setup();
+
+	blinkencat.setup();
+
+	while (1) {
+		blinkencat.loop();
+		while (kin.hasKey()) {
+			char key = kin.getKey();
+			if ((key >= '0') && (key < '0' + blinkencat.MODE_ENUM_MAX)) {
+				blinkencat.mode = (Blinkencat::Mode)(key - '0');
+			}
+		}
+	}
+
+	return 0;
+}