source import

README.md

@@ -1,2 +1,23 @@
-# avr-lib
+# MightyPork's AVR Library
-Utilities for AVR programming in C, aimed at m328 / Arduino.
+
+I program my Arduinos in plain C, compile it with `avr-gcc` and flash with `avrdude` (all on Linux).
+
+Whenever I learn how to do something, I make a library file and put it here.
+
+The code is tested and optimized for **ATmega328P**, which is used in most Arduinos. I use "Pro Mini" and "Nano".
+
+# How to use
+
+Link the `lib/` folder to your project, and make sure you add all lib `.c` files to your `Makefile`, so it builds are the needed code.
+
+Some library files don't have `.c`, but many do.
+
+## Useful things
+
+- To easily alias I/O pins, use `lib/pins.h`.
+- For Arduino pins, there are presets in `lib/arduino-pins.h`
+- Binary/byte manipulation utilities are in `lib/calc.h`
+- `lib/meta.h` contains some generally useful things that didn't fit elsewhere
+
+Each header file contains a comment block with explanation, which will help you understand them.
+

lib/adc.c

@@ -0,0 +1,46 @@
+#include <avr/io.h>
+#include <stdbool.h>
+
+#include "calc.h"
+#include "adc.h"
+
+/** Initialize the ADC */
+void adc_init()
+{
+	ADCSRA |= _BV(ADPS2) | _BV(ADPS1) | _BV(ADPS0);  // 128 prescaler -> 125 kHz
+	ADMUX  |= _BV(REFS0);  // Voltage reference
+	sbi(ADCSRA, ADEN);  // Enable ADC
+}
+
+
+/** Disable AD */
+void adc_disable()
+{
+	cbi(ADCSRA, ADEN);
+}
+
+
+/** Sample analog pin with 8-bit precision */
+uint8_t adc_read_byte(uint8_t channel)
+{
+	write_low_nibble(ADMUX, channel);  // Select channel to sample
+	sbi(ADMUX, ADLAR);  // Align result to left
+	sbi(ADCSRA, ADSC);  // Start conversion
+
+	while(bit_is_high(ADCSRA, ADSC));  // Wait for it...
+
+	return ADCH;  // The upper 8 bits of ADC result
+}
+
+
+/** Sample analog pin with 10-bit precision */
+uint16_t adc_read_word(uint8_t channel)
+{
+	write_low_nibble(ADMUX, channel);  // Select channel to sample
+	cbi(ADMUX, ADLAR);  // Align result to right
+	sbi(ADCSRA, ADSC);  // Start conversion
+
+	while(get_bit(ADCSRA, ADSC));  // Wait for it...
+
+	return ADCW;  // The whole ADC word (10 bits)
+}

lib/adc.h

@@ -0,0 +1,19 @@
+#pragma once
+
+/*
+  Utilities for build-in A/D converter
+*/
+
+#include <avr/io.h>
+
+/** Initialize the ADC */
+void adc_init();
+
+/** Disable AD (for power saving?) */
+void adc_disable();
+
+/** Sample analog pin with 8-bit precision */
+uint8_t adc_read_byte(uint8_t channel);
+
+/** Sample analog pin with 10-bit precision */
+uint16_t adc_read_word(uint8_t channel);

lib/arduino_pins.h

@@ -0,0 +1,42 @@
+#pragma once
+
+/**
+  Pin definitions for Arduino (Pro Mini with ATmega328P)
+*/
+
+#include "pins.h"
+
+#define D0 D,0
+#define D1 D,1
+#define D2 D,2
+#define D3 D,3
+#define D4 D,4
+#define D5 D,5
+#define D6 D,6
+#define D7 D,7
+#define D8 B,0
+#define D9 B,1
+#define D10 B,2
+
+// MOSI MISO SCK - not good for input
+#define D11 B,3
+#define D12 B,4
+#define D13 B,5
+
+#define D14 C,0
+#define D15 C,1
+#define D16 C,2
+#define D17 C,3
+#define D18 C,4
+#define D19 C,5
+#define D20 C,6
+#define D21 C,7
+
+#define A0 C,0
+#define A1 C,1
+#define A2 C,2
+#define A3 C,3
+#define A4 C,4
+#define A5 C,5
+#define A6 C,6
+#define A7 C,7

lib/calc.h

@@ -0,0 +1,89 @@
+#pragma once
+
+/**
+  Bit and byte manipulation utilities
+*/
+
+
+// --- Increment in range ---
+// when overflown, wraps within range. Lower bound < upper bound.
+// ..., upper bound excluded
+#define inc_wrap(var, min, max)  do { if ((var) >= (max - 1)) { (var) = (min); } else { (var)++; } } while(0)
+// ..., upper bound included
+#define inc_wrapi(var, min, max) inc_wrap((var), (min), (max) + 1)
+
+
+// --- Decrement in range ---
+// when underflown, wraps within range. Lower bound < upper bound.
+// ..., upper bound excluded
+#define dec_wrap(var, min, max)  do { if ((var) <= (min)) { (var) = (max) - 1; } else { (var)--; } } while(0)
+// ..., upper bound included
+#define dec_wrapi(var, min, max) dec_wrap((var), (min), (max) + 1)
+
+
+// --- Bit manipulation --
+
+// Set bit
+#define sbi(reg, bit) do { (reg) |=  (1 << (uint8_t)(bit)); } while(0)
+
+// Clear bit
+#define cbi(reg, bit) do { (reg) &= ~(1 << (uint8_t)(bit)); } while(0)
+
+// Get n-th bit
+#define read_bit(reg, bit) (((reg) >> (uint8_t)(bit)) & 0x1)
+#define get_bit(reg, bit)  read_bit(reg, bit)
+
+// Test n-th bit (Can't use bit_is_set, as it's redefined in sfr_def.h)
+#define bit_is_high(reg, bit) read_bit(reg, bit)
+#define bit_is_low(reg, bit)  (!read_bit(reg, bit))
+
+// Write value to n-th bit
+#define write_bit(reg, bit, value) do { (reg) = ((reg) & ~(1 << (uint8_t)(bit))) | (((uint8_t)(value) & 0x1) << (uint8_t)(bit)); } while(0)
+#define set_bit(reg, bit, value)   write_bit(reg, bit, value)
+
+// Invert n-th bit
+#define toggle_bit(reg, bit)       do { (reg) ^= (1 << (uint8_t)(bit)); } while(0)
+
+
+// --- Bit manipulation with pointer to variable ---
+
+// Set n-th bit in pointee
+#define sbi_p(reg_p, bit) do { (*(reg_p)) |=  (1 << (uint8_t)(bit)); } while(0)
+// Clear n-th bit in pointee
+#define cbi_p(reg_p, bit) do { (*(reg_p)) &= ~(1 << (uint8_t)(bit)); } while(0)
+
+// Get n-th bit in pointee
+#define read_bit_p(reg_p, bit) ((*(reg_p) >> (uint8_t)(bit)) & 0x1)
+#define get_bit_p(reg_p, bit)  read_bit_p(reg_p, bit)
+
+// Test n-th bit in pointee (Can't use bit_is_set, as it's redefined in sfr_def.h)
+#define bit_is_high_p(reg_p, bit) read_bit_p(reg_p, bit)
+#define bit_is_low_p(reg_p, bit)  (!read_bit_p(reg_p, bit))
+
+// Write value to a bit in pointee
+#define write_bit_p(reg_p, bit, value) do { *(reg_p) = (*(reg_p) & ~(1 << ((uint8_t)(bit) & 0x1))) | (((uint8_t)(value) & 0x1) << (uint8_t)(bit)); } while(0)
+#define set_bit_p(reg_p, bit, value)     write_bit_p(reg_p, bit, value)
+#define toggle_bit_p(reg_p, bit)       do { *(reg_p) ^= (1 << (uint8_t)(bit)); } while(0)
+
+
+// --- Nibble manipulation ---
+
+// Replace nibble in a byte
+#define write_low_nibble(reg, value)  do { (reg) = ((reg) & 0xF0) | ((uint8_t)(value) & 0xF); } while(0)
+#define write_high_nibble(reg, value) do { (reg) = ((reg) & 0x0F) | (((uint8_t)(value) & 0xF) << 4); } while(0)
+
+#define write_low_nibble_p(reg_p, value)  do { *(reg_p) = (*(reg_p) & 0xF0) | ((uint8_t)(value) & 0xF); } while(0)
+#define write_high_nibble_p(reg_p, value) do { *(reg_p) = (*(reg_p) & 0x0F) | (((uint8_t)(value) & 0xF) << 4); } while(0)
+
+
+// --- Range tests ---
+
+// Test if X is within low..high, regardless of bounds order
+#define in_range(x, low, high)  ((((low)  < (high)) && ((x) >= (low) && (x)  < (high))) || (((low) > (high)) && ((x) >= (high) && (x)  < (low))))
+// ..., include greater bound
+#define in_rangei(x, low, high) ((((low) <= (high)) && ((x) >= (low) && (x) <= (high))) || (((low) > (high)) && ((x) >= (high) && (x) <= (low))))
+
+// Test if X in low..high, wrap around ends if needed.
+#define in_range_wrap(x, low, high)  ((((low)  < (high)) && ((x) >= (low) && (x) < (high)))  || (((low) > (high)) && ((x) >= (low) || (x)  < (high))))
+// ..., include upper bound
+#define in_range_wrapi(x, low, high) ((((low) <= (high)) && ((x) >= (low) && (x) <= (high))) || (((low) > (high)) && ((x) >= (low) || (x) <= (high))))

lib/colors.h

@@ -0,0 +1,84 @@
+#pragma once
+
+/*
+  Some useful utilities for RGB color manipulation
+
+  The XXXc macros don't use cast, so they can be used in array initializers.
+
+  xrgb ... 3-byte true-color RGB (8 bits per component)
+  rgbXX ... XX-bit color value, with equal nr of bits per component
+
+  XX_r (_g, _b) ... extract component from the color, and convert it to 0..255
+*/
+
+
+typedef struct {
+	uint8_t r;
+	uint8_t g;
+	uint8_t b;
+} xrgb_t;
+
+typedef uint32_t rgb24_t;
+typedef uint16_t rgb15_t;
+typedef uint16_t rgb12_t;
+typedef uint8_t rgb6_t;
+
+
+#define xrgb(rr, gg, bb) ((xrgb_t)xrgbc(rr, gg, bb))
+// xrgb for constant array declarations
+#define xrgbc(rr, gg, bb) { .r = ((uint8_t)(rr)), .g = ((uint8_t)(gg)), .b = ((uint8_t)(bb)) }
+#define xrgb_r(c) ((uint8_t)(c.r))
+#define xrgb_g(c) ((uint8_t)(c.g))
+#define xrgb_b(c) ((uint8_t)(c.b))
+#define xrgb_rgb24(c) ((((rgb24_t)c.r) << 16) | (((rgb24_t)c.g) << 8) | (((rgb24_t)c.b)))
+#define xrgb_rgb15(c) (((((rgb15_t)c.r) & 0xF8) << 7) | ((((rgb15_t)c.g) & 0xF8) << 2) | ((((rgb15_t)c.b) & 0xF8) >> 3))
+#define xrgb_rgb12(c) (((((rgb12_t)c.r) & 0xF0) << 4) | ((((rgb12_t)c.g) & 0xF0)) | ((((rgb12_t)c.b) & 0xF0) >> 4))
+#define xrgb_rgb6(c)  (((((rgb6_t)c.r) & 0xC0) >> 2)  | ((((rgb6_t)c.g) & 0xC0) >> 4) | ((((rgb6_t)c.b) & 0xC0) >> 6))
+
+
+#define rgb24c(r,g,b) (((((rgb24_t)r) & 0xFF) << 16) | ((((rgb24_t)g) & 0xFF) << 8) | (((rgb24_t)b) & 0xFF))
+#define rgb24(r,g,b) ((rgb24_t) rgb24(r,g,b))
+
+#define rgb24_r(c) ((((rgb24_t) (c)) >> 16) & 0xFF)
+#define rgb24_g(c) ((((rgb24_t) (c)) >> 8) & 0xFF)
+#define rgb24_b(c) ((((rgb24_t) (c)) >> 0) & 0xFF)
+#define rgb24_xrgb(c) xrgb(rgb24_r(c), rgb24_g(c), rgb24_b(c))
+#define rgb24_xrgbc(c) xrgbc(rgb24_r(c), rgb24_g(c), rgb24_b(c))
+
+
+#define rgb15(r,g,b) ((rgb15_t) rgb15c(r,g,b))
+#define rgb15c(r,g,b) (((r & 0x1F) << 10) | ((g & 0x1F) << 5) | (b & 0x1F))
+
+#define rgb15_r(c) ((((rgb15_t) (c)) & 0x7C00) >> 7)
+#define rgb15_g(c) ((((rgb15_t) (c)) & 0x3E0) >> 2)
+#define rgb15_b(c) ((((rgb15_t) (c)) & 0x1F) << 3)
+#define rgb15_xrgb(c)  xrgb(rgb15_r(c), rgb15_g(c), rgb15_b(c))
+#define rgb15_rgb24(c) rgb24(rgb15_r(c), rgb15_g(c), rgb15_b(c))
+#define rgb15_rgb24c(c) rgb24c(rgb15_r(c), rgb15_g(c), rgb15_b(c))
+
+
+#define rgb12(r,g,b) ((rgb12_t) rgb12c(r,g,b))
+#define rgb12c(r,g,b) (((r & 0xF) << 8) | ((g & 0xF) << 4) | (b & 0xF))
+
+#define rgb12_r(c) ((((rgb12_t) (c)) & 0xF00) >> 4)
+#define rgb12_g(c) (((rgb12_t) (c)) & 0xF0)
+#define rgb12_b(c) (((r(rgb12_t) (c)gb) & 0x0F) << 4)
+#define rgb12_xrgb(c)  xrgb(rgb12_r(c), rgb12_g(c), rgb12_b(c))
+#define rgb12_xrgbc(c)  xrgbc(rgb12_r(c), rgb12_g(c), rgb12_b(c))
+#define rgb12_rgb24(c) rgb24(rgb12_r(c), rgb12_g(c), rgb12_b(c))
+#define rgb12_rgb24c(c) rgb24c(rgb12_r(c), rgb12_g(c), rgb12_b(c))
+
+
+#define rgb6(r,g,b) ((rgb6_t) rgb6c(r,g,b))
+#define rgb6c(r,g,b) (((r & 3) << 4) | ((g & 3) << 2) | (b & 3))
+
+#define rgb6_r(c) ((((rgb6_t) (c)) & 0x30) << 2)
+#define rgb6_g(c) ((((rgb6_t) (c)) & 0xC) << 4)
+#define rgb6_b(c) ((((rgb6_t) (c)) & 0x3) << 6)
+#define rgb6_xrgb(c)  xrgb(rgb6_r(c), rgb6_g(c), rgb6_b(c))
+#define rgb6_xrgbc(c)  xrgbc(rgb6_r(c), rgb6_g(c), rgb6_b(c))
+#define rgb6_rgb24(c) rgb24(rgb6_r(c), rgb6_g(c), rgb6_b(c))
+#define rgb6_rgb24c(c) rgb24c(rgb6_r(c), rgb6_g(c), rgb6_b(c))
+
+#define add_xrgb(x, y) ((xrgb_t) { (((y).r > (255 - (x).r)) ? 255 : ((x).r + (y).r)), (((y).g > (255 - (x).g)) ? 255 : ((x).g + (y).g)), (((y).b > 255 - (x).b) ? 255 : ((x).b + (y).b)) })
+

lib/debounce.c

@@ -0,0 +1,45 @@
+#include <avr/io.h>
+#include <stdbool.h>
+
+#include "debounce.h"
+#include "calc.h"
+#include "pins.h"
+#include "debo_config.h"
+
+/** Debounce data array */
+uint8_t debo_next_slot = 0;
+
+uint8_t debo_register(PORT_P reg, uint8_t bit, bool invert)
+{
+	debo_slots[debo_next_slot] = (debo_slot_t){
+		.reg = reg,
+		.bit = bit | ((invert & 1) << 7) | (get_bit_p(reg, bit) << 6), // bit 7 = invert, bit 6 = state
+		.count = 0,
+	};
+
+	return debo_next_slot++;
+}
+
+
+/** Check debounced pins, should be called periodically. */
+void debo_tick()
+{
+	for (uint8_t i = 0; i < debo_next_slot; i++) {
+		// current pin value (right 3 bits, xored with inverse bit)
+		bool value = get_bit_p(debo_slots[i].reg, debo_slots[i].bit & 0x7);
+
+		if (value != get_bit(debo_slots[i].bit, 6)) {
+
+			// different pin state than last recorded state
+			if (debo_slots[i].count < DEBO_TICKS) {
+				debo_slots[i].count++;
+			} else {
+				// overflown -> latch value
+				set_bit(debo_slots[i].bit, 6, value); // set state bit
+				debo_slots[i].count = 0;
+			}
+		} else {
+			debo_slots[i].count = 0; // reset the counter
+		}
+	}
+}

lib/debounce.h

@@ -0,0 +1,63 @@
+#pragma once
+
+/**
+  An implementation of button debouncer.
+
+  ----
+
+  You must provide a config file debo_config.h (next to your main.c)
+
+  Example:
+    #pragma once
+    #define DEBO_CHANNELS 2
+    #define DDEBO_TICKS 5
+
+  ----
+
+  A pin is registered like this:
+
+    #define BTN1 B,0
+    #define BTN2 B,1
+
+    debo_add(BTN0);  // The function returns number assigned to the pin (0, 1, ...)
+    debo_add_rev(BTN1);  // active low
+    debo_register(&PINB, PB2, 0);  // direct access - register, pin & invert
+
+  Then periodically call the tick function (perhaps in a timer interrupt):
+
+    debo_tick();
+
+  To check if input is active, use
+
+    debo_get_pin(0); // state of input #0 (registered first)
+    debo_get_pin(1); // state of input #1 (registered second)
+*/
+
+#include <avr/io.h>
+#include <stdbool.h>
+
+#include "calc.h"
+#include "pins.h"
+#include "debo_config.h"
+
+/* Internal deboucer entry */
+typedef struct {
+	PORT_P reg;    // pointer to IO register
+	uint8_t bit;   // bits 6 and 7 of this hold "state" & "invert" flag
+	uint8_t count; // number of ticks this was in the new state
+} debo_slot_t;
+
+debo_slot_t debo_slots[DEBO_CHANNELS];
+
+/** Add a pin for debouncing */
+#define debo_add_rev(io) debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 1)
+#define debo_add(io)  debo_register(&io2pin(io_pack(io)), io2n(io_pack(io)), 0)
+
+/** Add a pin for debouncing (low level function) */
+uint8_t debo_register(PORT_P pin_reg_pointer, uint8_t bit, bool invert);
+
+/** Check debounced pins, should be called periodically. */
+void debo_tick();
+
+/** Get a value of debounced pin */
+#define debo_get_pin(i) (get_bit(debo_slots[i].bit, 6) ^ get_bit(debo_slots[i].bit, 7))

lib/hsl.c

@@ -0,0 +1,89 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include "colors.h"
+#include "hsl.h"
+
+#ifdef HSL_LINEAR
+	const uint8_t FADE_128[] = {
+		0,	1,	1,	1,	1,	1,	2,	2,	2,	2,	2,	3,	3,	3,	4,	4,	4,	4,
+		5,	5,	6,	6,	6,	7,	7,	8,	8,	8,	9,	10,	10,	10,	11,	12,	13,	14,
+		14,	15,	16,	17,	18,	20,	21,	22,	24,	26,	27,	28,	30,	31,	32,	34,	35,	36,
+		38,	39,	40,	41,	42,	44,	45,	46,	48,	49,	50,	52,	54,	56,	58,	59,	61,	63,
+		65,	67,	68,	69,	71,	72,	74,	76,	78,	80,	82,	85,	88,	90,	92,	95,	98,	100,
+		103, 106, 109, 112, 116, 119, 122, 125, 129, 134, 138, 142,	147, 151,
+		153, 156, 160, 163, 165, 170, 175, 180, 185, 190, 195, 200, 207, 214, 218,
+		221, 225, 228, 232, 234, 241, 248, 254, 255
+	};
+#endif
+
+// based on: https://github.com/lewisd32/avr-hsl2rgb
+xrgb_t hsl2xrgb(const hsl_t cc)
+{
+	// 0 .. 256*3
+	const uint16_t hh = (uint16_t) cc.h * 3;
+	const uint8_t hue_mod = hh % 256;
+
+	uint8_t r_temp, g_temp, b_temp;
+	if (hh < 256) {
+		r_temp = hue_mod ^ 255;
+		g_temp = hue_mod;
+		b_temp = 0;
+	} else if (hh < 512) {
+		r_temp = 0;
+		g_temp = hue_mod ^ 255;
+		b_temp = hue_mod;
+	} else if (hh < 768) {
+		r_temp = hue_mod;
+		g_temp = 0;
+		b_temp = hue_mod ^ 255;
+	} else {
+		r_temp = 0;
+		g_temp = 0;
+		b_temp = 0;
+	}
+
+	const uint8_t inverse_sat = (cc.s ^ 255);
+
+	xrgb_t rgb;
+
+	uint8_t t8;
+	uint16_t t16;
+
+#ifdef HSL_LINEAR
+	const uint8_t bri = FADE_128[cc.l>>1];
+#else
+	const uint8_t bri = cc.l;
+#endif
+
+	t8 = r_temp;
+	t16 = t8 * cc.s + t8;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	t8 = t8 + inverse_sat;
+	t16 = t8 * bri;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	rgb.r = t8;
+
+	t8 = g_temp;
+	t16 = t8 * cc.s;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	t8 = t8 + inverse_sat;
+	t16 = t8 * bri;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	rgb.g = t8;
+
+	t8 = b_temp;
+	t16 = t8 * cc.s;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	t8 = t8 + inverse_sat;
+	t16 = t8 * bri;
+	t16 = t16 + t8;
+	t8 = t16 >> 8;
+	rgb.b = t8;
+
+	return rgb;
+}

lib/hsl.h

@@ -0,0 +1,19 @@
+#pragma once
+
+/*
+  HSL support (addition to colors.h)
+*/
+
+#include "colors.h"
+
+// Define HSL_LINEAR to get more linear brightness in hsl->rgb conversion
+
+// HSL data structure
+typedef struct {
+	uint8_t h;
+	uint8_t s;
+	uint8_t l;
+} hsl_t;
+
+/* Convert HSL to XRGB */
+xrgb_t hsl2xrgb(const hsl_t color);

lib/lcd.c

@@ -0,0 +1,284 @@
+#include <stdbool.h>
+#include <stdint.h>
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <util/delay.h>
+
+#include "calc.h"
+#include "pins.h"
+#include "nsdelay.h"
+#include "lcd.h"
+#include "lcd_config.h"
+
+// Start address of rows
+const uint8_t LCD_ROW_ADDR[] = {0x00, 0x40, 0x14, 0x54};
+
+// Internal prototypes
+void _lcd_mode_r();
+void _lcd_mode_w();
+void _lcd_clk();
+void _lcd_wait_bf();
+void _lcd_write_byte(uint8_t bb);
+uint8_t _lcd_read_byte();
+
+
+// Write utilities
+#define _lcd_write_low(bb)  _lcd_write_nibble((bb) & 0x0F)
+#define _lcd_write_high(bb) _lcd_write_nibble(((bb) & 0xF0) >> 4)
+#define _lcd_write_nibble(nib) do {                \
+	write_pin(LCD_D7, get_bit((nib), 3));     \
+	write_pin(LCD_D6, get_bit((nib), 2));     \
+	write_pin(LCD_D5, get_bit((nib), 1));     \
+	write_pin(LCD_D4, get_bit((nib), 0));     \
+} while(0)
+
+
+// 0 W, 1 R
+bool _lcd_mode;
+
+
+/** Initialize the display */
+void lcd_init()
+{
+	// configure pins as output
+	as_output(LCD_E);
+	as_output(LCD_RW);
+	as_output(LCD_RS);
+	_lcd_mode = 1;  // force data pins to output
+	_lcd_mode_w();
+
+	// Magic sequence to invoke Cthulhu (or enter 4-bit mode)
+	_delay_ms(16);
+	_lcd_write_nibble(0b0011);
+	_lcd_clk();
+	_delay_ms(5);
+	_lcd_clk();
+	_delay_ms(5);
+	_lcd_clk();
+	_delay_ms(5);
+	_lcd_write_nibble(0b0010);
+	_lcd_clk();
+	_delay_us(100);
+
+	// Configure the display
+	lcd_write_command(LCD_IFACE_4BIT_2LINE);
+	lcd_write_command(LCD_DISABLE);
+	lcd_write_command(LCD_CLEAR);
+	lcd_write_command(LCD_MODE_INC);
+
+	// mark as enabled
+	lcd_enable();
+}
+
+
+/** Send a pulse on the ENABLE line */
+void _lcd_clk()
+{
+	pin_up(LCD_E);
+	delay_ns(420);
+	pin_down(LCD_E);
+}
+
+
+/** Enter READ mode */
+void _lcd_mode_r()
+{
+	if (_lcd_mode == 1) return;  // already in R mode
+
+	pin_up(LCD_RW);
+
+	as_input_pu(LCD_D7);
+	as_input_pu(LCD_D6);
+	as_input_pu(LCD_D5);
+	as_input_pu(LCD_D4);
+
+	_lcd_mode = 1;
+}
+
+
+/** Enter WRITE mode */
+void _lcd_mode_w()
+{
+	if (_lcd_mode == 0) return;  // already in W mode
+
+	pin_down(LCD_RW);
+
+	as_output(LCD_D7);
+	as_output(LCD_D6);
+	as_output(LCD_D5);
+	as_output(LCD_D4);
+
+	_lcd_mode = 0;
+}
+
+
+/** Read a byte */
+uint8_t _lcd_read_byte()
+{
+	_lcd_mode_r();
+
+	uint8_t res = 0;
+
+	_lcd_clk();
+	res = (read_pin(LCD_D7) << 7) | (read_pin(LCD_D6) << 6) | (read_pin(LCD_D5) << 5) | (read_pin(LCD_D4) << 4);
+
+	_lcd_clk();
+	res |= (read_pin(LCD_D7) << 3) | (read_pin(LCD_D6) << 2) | (read_pin(LCD_D5) << 1) | (read_pin(LCD_D4) << 0);
+
+	return res;
+}
+
+
+/** Write an instruction byte */
+void lcd_write_command(uint8_t bb)
+{
+	_lcd_wait_bf();
+	pin_down(LCD_RS);  // select instruction register
+	_lcd_write_byte(bb);    // send instruction byte
+}
+
+
+/** Write a data byte */
+void lcd_write_data(uint8_t bb)
+{
+	_lcd_wait_bf();
+	pin_up(LCD_RS);  // select data register
+	_lcd_write_byte(bb);  // send data byte
+}
+
+
+/** Read BF & Address */
+uint8_t lcd_read_bf_addr()
+{
+	pin_down(LCD_RS);
+	return _lcd_read_byte();
+}
+
+
+/** Read CGRAM or DDRAM */
+uint8_t lcd_read_ram()
+{
+	pin_up(LCD_RS);
+	return _lcd_read_byte();
+}
+
+
+/** Write a byte using the 8-bit interface */
+void _lcd_write_byte(uint8_t bb)
+{
+	_lcd_mode_w();  // enter W mode
+
+	_lcd_write_high(bb);
+	_lcd_clk();
+
+	_lcd_write_low(bb);
+	_lcd_clk();
+}
+
+
+
+/** Wait until the device is ready */
+void _lcd_wait_bf()
+{
+	uint8_t d = 0;
+	while(d++ < 120 && lcd_read_bf_addr() & _BV(7))
+		_delay_us(1);
+}
+
+
+/** Send a string to LCD */
+void lcd_puts(char* str_p)
+{
+	while (*str_p)
+		lcd_putc(*str_p++);
+}
+
+
+/** Sedn a char to LCD */
+void lcd_putc(const char c)
+{
+	lcd_write_data(c);
+}
+
+
+/** Set cursor position */
+void lcd_xy(const uint8_t x, const uint8_t y)
+{
+	lcd_set_addr(LCD_ROW_ADDR[y] + (x));
+}
+
+
+uint8_t _lcd_old_cursor = CURSOR_NONE;
+bool _lcd_enabled = false;
+
+/** Set LCD cursor. If not enabled, only remember it. */
+void lcd_cursor(uint8_t type)
+{
+	_lcd_old_cursor = (type & CURSOR_BOTH);
+
+	if (_lcd_enabled) lcd_write_command(LCD_CURSOR_NONE | _lcd_old_cursor);
+}
+
+
+/** Display display (preserving cursor) */
+void lcd_disable()
+{
+	lcd_write_command(LCD_DISABLE);
+	_lcd_enabled = false;
+}
+
+
+/** Enable display (restoring cursor) */
+void lcd_enable()
+{
+	_lcd_enabled = true;
+	lcd_cursor(_lcd_old_cursor);
+}
+
+
+/** Go home */
+void lcd_home()
+{
+	lcd_write_command(LCD_HOME);
+}
+
+
+/** Clear the screen */
+void lcd_clear()
+{
+	lcd_write_command(LCD_CLEAR);
+}
+
+
+/** Define a glyph */
+void lcd_define_glyph(const uint8_t index, const uint8_t* array)
+{
+	lcd_set_addr_cgram(index * 8);
+	for (uint8_t i = 0; i < 8; ++i)	{
+		lcd_write_data(array[i]);
+	}
+}
+
+
+/** Define a glyph */
+void lcd_define_glyph_pgm(const uint8_t index, const uint8_t* array)
+{
+	lcd_set_addr_cgram(index * 8);
+	for (uint8_t i = 0; i < 8; ++i)	{
+		lcd_write_data(pgm_read_byte(&array[i]));
+	}
+}
+
+
+/** Set address in CGRAM */
+void lcd_set_addr_cgram(const uint8_t acg)
+{
+	lcd_write_command(0b01000000 | ((acg) & 0b00111111));
+}
+
+
+/** Set address in DDRAM */
+void lcd_set_addr(const uint8_t add)
+{
+	lcd_write_command(0b10000000 | ((add) & 0b01111111));
+}

lib/lcd.h

@@ -0,0 +1,130 @@
+#pragma once
+
+/*
+  HD44780 LCD display driver - 4-bit mode
+
+  LCD pins are configured using a file lcd_config.h, which you
+  have to add next to your main.c file.
+
+  Content can be something like this:
+
+    #pragma once
+    #include "lib/arduino_pins.h"
+    #define LCD_RS D10
+    #define LCD_RW D11
+    #define LCD_E  D12
+    #define LCD_D4 D13
+    #define LCD_D5 D14
+    #define LCD_D6 D15
+    #define LCD_D7 D16
+
+*/
+
+#include <stdint.h>
+#include "lcd_config.h"
+
+// Commands
+
+// Clear screen (reset)
+#define LCD_CLEAR 0b00000001
+// Move cursor to (0,0), unshift...
+#define LCD_HOME  0b00000010
+
+// Set mode: Increment + NoShift
+#define LCD_MODE_INC         0b00000110
+// Set mode: Increment + Shift
+#define LCD_MODE_INC_SHIFT   0b00000111
+
+// Set mode: Decrement + NoShift
+#define LCD_MODE_DEC         0b00000100
+// Set mode: Decrement + Shift
+#define LCD_MODE_DEC_SHIFT   0b00000101
+
+// Disable display (data remains untouched)
+#define LCD_DISABLE          0b00001000
+
+// Disable cursor
+#define LCD_CURSOR_NONE      0b00001100
+// Set cursor to still underscore
+#define LCD_CURSOR_BAR       0b00001110
+// Set cursor to blinking block
+#define LCD_CURSOR_BLINK     0b00001101
+// Set cursor to both of the above at once
+#define LCD_CURSOR_BOTH      (LCD_CURSOR_BAR | LCD_CURSOR_BLINK)
+
+// Move cursor
+#define LCD_MOVE_LEFT  0b00010000
+#define LCD_MOVE_RIGHT 0b00010100
+
+// Shift display
+#define LCD_SHIFT_LEFT  0b00011000
+#define LCD_SHIFT_RIGHT 0b00011100
+
+// Set iface to 5x7 font, 1-line
+#define LCD_IFACE_4BIT_1LINE 0b00100000
+#define LCD_IFACE_8BIT_1LINE 0b00110000
+// Set iface to 5x7 font, 2-line
+#define LCD_IFACE_4BIT_2LINE 0b00101000
+#define LCD_IFACE_8BIT_2LINE 0b00111000
+
+
+/** Initialize the display */
+void lcd_init();
+
+/** Write an instruction byte */
+void lcd_write_command(uint8_t bb);
+
+/** Write a data byte */
+void lcd_write_data(uint8_t bb);
+
+/** Read BF & Address */
+uint8_t lcd_read_bf_addr();
+
+/** Read CGRAM or DDRAM */
+uint8_t lcd_read_ram();
+
+/** Send a string to LCD */
+void lcd_puts(char* str_p);
+
+/** Sedn a char to LCD */
+void lcd_putc(const char c);
+
+/** Show string at X, Y */
+#define lcd_str_xy(x, y, str_p) do { lcd_xy((x), (y)); lcd_puts((str_p)); } while(0)
+
+/** Show char at X, Y */
+#define lcd_char_xy(x, y, c) do { lcd_xy((x), (y)); lcd_putc((c)); } while(0)
+
+/** Set cursor position */
+void lcd_xy(const uint8_t x, const uint8_t y);
+
+/** Set LCD cursor. If not enabled, only remember it. */
+#define CURSOR_NONE  0b00
+#define CURSOR_BAR   0b10
+#define CURSOR_BLINK 0b01
+#define CURSOR_BOTH  0b11
+void lcd_cursor(uint8_t type);
+
+/** Display display (preserving cursor) */
+void lcd_disable();
+
+/** Enable display (restoring cursor) */
+void lcd_enable();
+
+/** Go home */
+void lcd_home();
+
+/** Clear the screen */
+void lcd_clear();
+
+/** Define a glyph */
+void lcd_define_glyph(const uint8_t index, const uint8_t* array);
+
+/** Define a glyph that's in PROGMEM */
+void lcd_define_glyph_pgm(const uint8_t index, const uint8_t* array);
+
+/** Set address in CGRAM */
+void lcd_set_addr_cgram(const uint8_t acg);
+
+/** Set address in DDRAM */
+void lcd_set_addr(const uint8_t add);

lib/loops.h

@@ -0,0 +1,22 @@
+#pragma once
+
+/**
+  Custom loops
+*/
+
+// Repeat code n times (uint8_t counter)
+#define repeat(count) repeat_aux(count, _repeat_##__COUNTER__)
+#define repeat_aux(count, cntvar) for (uint8_t cntvar = 0; cntvar < (count); cntvar++)
+
+// Repeat code n times (uint16_t counter)
+#define repeatx(count) repeatx_aux(count, _repeatx_##__COUNTER__)
+#define repeatx_aux(count, cntvar) for (uint16_t cntvar = 0; cntvar < (count); cntvar++)
+
+// Repeat with custom counter name (uint8_t)
+#define loop(var, count) repeat_aux(count, var)
+// ..., uint16_t
+#define loopx(var, count) repeatx_aux(count, var)
+
+// Do until condition is met
+#define until(what) while(!(what))
+

lib/meta.h

@@ -0,0 +1,6 @@
+#pragma once
+
+/** Weird constructs for the compiler */
+
+// general macros
+#define SECTION(pos) __attribute__((naked, used, section(pos)))

lib/nsdelay.h

@@ -0,0 +1,21 @@
+#pragma once
+
+/**
+  Functions for precise delays (nanoseconds / cycles)
+*/
+
+#include <avr/io.h>
+#include <util/delay_basic.h>
+#include <stdint.h>
+
+/* Convert nanoseconds to cycle count */
+#define ns2cycles(ns)  ( (ns) / (1000000000L / (signed long) F_CPU) )
+
+/** Wait c cycles */
+#define delay_c(c)  (((c) > 0) ? __builtin_avr_delay_cycles(c) :  __builtin_avr_delay_cycles(0))
+
+/** Wait n nanoseconds, plus c cycles  */
+#define delay_ns_c(ns, c)  delay_c(ns2cycles(ns) + (c))
+
+/** Wait n nanoseconds  */
+#define delay_ns(ns)  delay_c(ns2cycles(ns))

lib/pins.h

@@ -0,0 +1,107 @@
+#pragma once
+
+/**
+  This file provides macros for pin manipulation.
+
+  You can define your application pins like so:
+
+      // Led at PORTB, pin 1
+      #define LED B,1
+
+      // Switch at PORTD, pin 7
+      #define SW1 D,7
+
+  Now you can use macros from this file to wirh with the pins, eg:
+
+      as_output(LED);
+      as_input(SW1);
+      pullup_on(SW1);
+
+      toggle_pin(LED);
+      while (pin_is_low(SW1));
+
+  - The macros io2XXX() can be used to get literal name of register associated with the pin.
+  - io2n() provides pin number.
+  - The XXX_aux() macros are internal and should not be used elsewhere.
+  - The io_pack() macro is used to pass pin (io) to other macro without expanding it.
+*/
+
+#include <avr/io.h>
+#include "calc.h"
+
+
+// Get particular register associated with the name X (eg. D -> PORTD)
+#define reg_ddr(X) DDR ## X
+#define reg_port(X) PORT ## X
+#define reg_pin(X) PIN ## X
+
+#define io2ddr_aux(reg, bit) reg_ddr(reg)
+#define io2ddr(io) io2ddr_aux(io)
+#define io2port_aux(reg, bit) reg_port(reg)
+#define io2port(io) io2port_aux(io)
+#define io2pin_aux(reg, bit) reg_pin(reg)
+#define io2pin(io) io2pin_aux(io)
+#define io2n_aux(reg, bit) bit
+#define io2n(io) io2n_aux(io)
+
+#define io_pack(port, bit) port, bit
+
+
+// pointer to port
+typedef volatile uint8_t* PORT_P;
+// number of bit in port
+typedef uint8_t BIT_N;
+
+
+// === pin manipulation ===
+#define set_pin_aux(port, bit) sbi(reg_port(port), (bit))
+#define clear_pin_aux(port, bit) cbi(reg_port(port), (bit))
+#define read_pin_aux(port, bit) get_bit(reg_pin(port), (bit))
+#define write_pin_aux(port, bit, value) set_bit(reg_port(port), (bit), (value))
+#define toggle_pin_aux(port, bit) sbi(reg_pin(port), (bit))
+
+
+#define pin_up(io) set_pin_aux(io)
+#define pin_high(io) set_pin_aux(io)
+
+#define pin_down(io) clear_pin_aux(io)
+#define pin_low(io) clear_pin_aux(io)
+
+#define get_pin(io) read_pin_aux(io)
+#define read_pin(io) read_pin_aux(io)
+
+#define pin_is_low(io) !read_pin_aux(io)
+#define pin_is_high(io) read_pin_aux(io)
+
+#define set_pin(io, value) write_pin_aux(io, (value))
+#define write_pin(io, value) write_pin_aux(io, (value))
+#define toggle_pin(io) toggle_pin_aux(io)
+
+
+
+// setting pin direction
+#define as_input_aux(port, bit) cbi(reg_ddr(port), (bit))
+#define as_output_aux(port, bit) sbi(reg_ddr(port), (bit))
+#define set_dir_aux(port, bit, dir) write_bit(reg_ddr(port), (bit), (dir))
+
+
+#define as_input(io) as_input_aux(io)
+#define as_input_pu(io) do { as_input_aux(io); pullup_enable_aux(io); } while(0)
+
+#define as_output(io) as_output_aux(io)
+#define set_dir(io, dir) set_dir_aux(io, (dir))
+
+
+// setting pullup
+#define pullup_enable_aux(port, bit) sbi(reg_port(port), (bit))
+#define pullup_disable_aux(port, bit) cbi(reg_port(port), (bit))
+#define set_pullup_aux(port, bit, on) write_bit(reg_port(port), (bit), (on))
+
+
+#define pullup_enable(io) pullup_enable_aux(io)
+#define pullup_on(io) pullup_enable_aux(io)
+
+#define pullup_disable(io) pullup_disable_aux(io)
+#define pullup_off(io) pullup_disable_aux(io)
+
+#define set_pullup(io, on) set_pullup_aux(io, on)

lib/uart.c

@@ -0,0 +1,97 @@
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <util/delay.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "uart.h"
+
+void _uart_init_do(uint16_t ubrr) {
+	/*Set baud rate */
+	UBRR0H = (uint8_t) (ubrr >> 8);
+	UBRR0L = (uint8_t) ubrr;
+
+	// Enable Rx and Tx
+	UCSR0B = (1 << RXEN0) | (1 << TXEN0);
+
+	// 8-bit data, 1 stop bit
+	UCSR0C = (0b11 << UCSZ00);
+}
+
+
+/** Enable or disable RX ISR */
+void uart_isr_rx(bool yes)
+{
+	if(yes) {
+		UCSR0B |= (1 << RXCIE0);
+	} else {
+		UCSR0B &= ~(1 << RXCIE0);
+	}
+}
+
+/** Enable or disable TX ISR (1 byte is sent) */
+void uart_isr_tx(bool yes)
+{
+	if(yes) {
+		UCSR0B |= (1 << TXCIE0);
+	} else {
+		UCSR0B &= ~(1 << TXCIE0);
+	}
+}
+
+/** Enable or disable DRE ISR (all is sent) */
+void uart_isr_dre(bool yes)
+{
+	if(yes) {
+		UCSR0B |= (1 << UDRIE0);
+	} else {
+		UCSR0B &= ~(1 << UDRIE0);
+	}
+}
+
+
+
+
+/** Send byte over UART */
+void uart_tx(uint8_t data)
+{
+	// Wait for transmit buffer
+	while (!uart_tx_ready());
+	// send it
+	UDR0 = data;
+}
+
+/** Send string over UART */
+void uart_puts(const char* str)
+{
+	while (*str) {
+		uart_tx(*str++);
+	}
+}
+
+/** Send progmem string over UART */
+void uart_puts_pgm(const char* str)
+{
+	char c;
+	while ((c = pgm_read_byte(str++))) {
+		uart_tx(c);
+	}
+}
+
+/** Receive one byte over UART */
+uint8_t uart_rx()
+{
+	// Wait for data to be received
+	while (!uart_rx_ready());
+	// Get and return received data from buffer
+	return UDR0;
+}
+
+/** Clear receive buffer */
+void uart_flush()
+{
+	uint8_t dummy;
+	while (UCSR0A & (1 << RXC0))
+		dummy = UDR0;
+}
+

lib/uart.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <util/delay.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+/** Init UART for given baudrate */
+#define uart_init(baud) _uart_init_do(F_CPU / 16 / (baud) - 1)
+
+void _uart_init_do(uint16_t ubrr);
+
+/** Check if there's a byte in the RX register */
+#define uart_rx_ready() (0 != (UCSR0A & (1 << RXC0)))
+
+/** Check if transmission of everything is done */
+#define uart_tx_ready() (0 != (UCSR0A & (1 << UDRE0)))
+
+/** Enable or disable RX ISR */
+void uart_isr_rx(bool enable);
+
+/** Enable or disable TX ISR (1 byte is sent) */
+void uart_isr_tx(bool enable);
+
+/** Enable or disable DRE ISR (all is sent) */
+void uart_isr_dre(bool enable);
+
+/** Send byte over UART */
+#define uart_putc(data) uart_tx(data)
+void uart_tx(uint8_t data);
+
+/** Send string over UART */
+void uart_puts(const char* str);
+
+/** Send progmem string over UART */
+void uart_puts_pgm(const char* str);
+
+/** Receive one byte over UART */
+uint8_t uart_rx();
+
+/** Clear receive buffer */
+void uart_flush();

lib/ws_rgb.h

@@ -0,0 +1,127 @@
+#pragma once
+
+/**
+  Utils for driving a WS28xx (tested on WS2812B) RGB LED strips.
+
+  It's implemented as macros to avoid overhead when passing values, and to
+  enable driving multiple strips at once.
+
+  To avoid bloating your code, try to reduce the number of invocations -
+  compute color and then send it.
+
+  [IMPORTANT]
+
+  Some seemingly random influences can ruin the communication.
+  If you have enough memory, consider preparing the colors in array,
+  and sending this array using one of the "ws_send_XXX_array" macros.
+
+*/
+
+#include <avr/io.h>
+
+#include "pins.h"
+#include "nsdelay.h"
+#include "colors.h"
+
+/* Driver code for WS2812B */
+
+// --- timing constraints (NS) ---
+
+#ifndef WS_T_1H
+# define WS_T_1H  700
+#endif
+
+#ifndef WS_T_1L
+# define WS_T_1L  150
+#endif
+
+#ifndef WS_T_0H
+# define WS_T_0H  150
+#endif
+
+#ifndef WS_T_0L
+# define WS_T_0L  700
+#endif
+
+#ifndef WS_T_LATCH
+# define WS_T_LATCH 7000
+#endif
+
+
+/** Wait long enough for the colors to show */
+#define ws_show() do {delay_ns_c(WS_T_LATCH, 0); } while(0)
+
+
+/** Send one byte to the RGB strip */
+#define ws_send_byte(io, bb) do {										\
+	for (volatile int8_t __ws_tmp = 7; __ws_tmp >= 0; --__ws_tmp) {		\
+		if ((bb) & (1 << __ws_tmp)) {									\
+			pin_high(io_pack(io)); delay_ns_c(WS_T_1H, -2);				\
+			pin_low(io_pack(io)); delay_ns_c(WS_T_1L, -10);				\
+		} else {														\
+			pin_high(io_pack(io)); delay_ns_c(WS_T_0H, -2);				\
+			pin_low(io_pack(io)); delay_ns_c(WS_T_0L, -10);				\
+		}																\
+	}																	\
+} while(0)
+
+
+/** Send R,G,B color to the strip */
+#define ws_send_rgb(io, r, g, b) do {			\
+	ws_send_byte(io_pack(io), g);				\
+	ws_send_byte(io_pack(io), r);				\
+	ws_send_byte(io_pack(io), b);				\
+} while(0)
+
+/** Send a RGB struct */
+#define ws_send_xrgb(io, xrgb) ws_send_rgb(io_pack(io), (xrgb).r, (xrgb).g, (xrgb).b)
+
+/** Send color hex */
+#define ws_send_rgb24(io, rgb) ws_send_rgb(io_pack(io), rgb24_r(rgb), rgb24_g(rgb), rgb24_b(rgb))
+#define ws_send_rgb15(io, rgb) ws_send_rgb(io_pack(io), rgb15_r(rgb), rgb15_g(rgb), rgb15_b(rgb))
+#define ws_send_rgb12(io, rgb) ws_send_rgb(io_pack(io), rgb12_r(rgb), rgb12_g(rgb), rgb12_b(rgb))
+#define ws_send_rgb6(io, rgb)  ws_send_rgb(io_pack(io), rgb6_r(rgb),  rgb6_g(rgb),  rgb6_b(rgb))
+
+/** Send array of colors */
+#define ws_send_xrgb_array(io, rgbs, length) __ws_send_array_proto(io_pack(io), (rgbs), (length), xrgb)
+#define ws_send_rgb24_array(io, rgbs, length) __ws_send_array_proto(io_pack(io), (rgbs), (length), rgb24)
+#define ws_send_rgb15_array(io, rgbs, length) __ws_send_array_proto(io_pack(io), (rgbs), (length), rgb15)
+#define ws_send_rgb12_array(io, rgbs, length) __ws_send_array_proto(io_pack(io), (rgbs), (length), rgb12)
+#define ws_send_rgb6_array(io, rgbs, length) __ws_send_array_proto(io_pack(io), (rgbs), (length), rgb6)
+
+// prototype for sending array. it's ugly, sorry.
+#define __ws_send_array_proto(io, rgbs, length, style) do {						\
+	for (uint8_t __ws_sap_i = 0; __ws_sap_i < length; __ws_sap_i++) {			\
+		style ## _t __ws_sap2 = (rgbs)[__ws_sap_i];								\
+		ws_send_ ## style(io_pack(io), __ws_sap2);								\
+	}																			\
+} while(0)
+
+/** Send a 2D array to a zig-zag display */
+#define ws_send_xrgb_array_zigzag(io, rgbs, width, height) do {				\
+	int8_t __ws_sxaz_y, __ws_sxaz_x;										\
+	for(__ws_sxaz_y = 0; __ws_sxaz_y < (height); __ws_sxaz_y ++) {			\
+		for(__ws_sxaz_x = 0; __ws_sxaz_x < (width); __ws_sxaz_x++) {		\
+			ws_send_xrgb(io_pack(io), (rgbs)[__ws_sxaz_y][__ws_sxaz_x]);	\
+		}																	\
+		__ws_sxaz_y++;														\
+		for(__ws_sxaz_x = (width) - 1; __ws_sxaz_x >= 0; __ws_sxaz_x--) {	\
+			ws_send_xrgb(io_pack(io), (rgbs)[__ws_sxaz_y][__ws_sxaz_x]);	\
+		}																	\
+	}																		\
+} while(0)
+
+
+/** Send a linear array to a zig-zag display as a n*m board (row-by-row) */
+#define ws_send_xrgb_array_zigzag_linear(io, rgbs, width, height) do {					\
+	int8_t __ws_sxazl_x, __ws_sxazl_y;													\
+	for(__ws_sxazl_y = 0; __ws_sxazl_y < (height); __ws_sxazl_y++) {					\
+		for(__ws_sxazl_x = 0; __ws_sxazl_x < (width); __ws_sxazl_x++) {					\
+			ws_send_xrgb(io_pack(io), (rgbs)[__ws_sxazl_y * (width) + __ws_sxazl_x]);	\
+		}																				\
+		__ws_sxazl_y++;																	\
+		for(__ws_sxazl_x = width-1; __ws_sxazl_x >=0; __ws_sxazl_x--) {					\
+			ws_send_xrgb(io_pack(io), (rgbs)[__ws_sxazl_y * (width) + __ws_sxazl_x]);	\
+		}																				\
+	}																					\
+} while(0)

lib_tests/lib

@@ -0,0 +1 @@
+../lib

lib_tests/run_tests.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+dir=/tmp/avrclib_unittest
+
+[ -d "$dir" ] || mkdir "$dir"
+
+gcc test_calc.c -o "$dir/test_calc" &&  "$dir/test_calc"
+

lib_tests/test_calc.c

@@ -0,0 +1,356 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include "lib/calc.h"
+
+void main()
+{
+	printf("== calc.h ==\n");
+
+	int i;
+	int a;
+
+	printf("fn: inc_wrap()\n");
+	{
+		// normal operation
+		a = 1;
+		inc_wrap(a, 0, 15);
+		assert(a == 2);
+
+		// overflow
+		a = 14;
+		inc_wrap(a, 0, 15);
+		assert(a == 0);
+	}
+
+
+	printf("fn: inc_wrapi()\n");
+	{
+		// normal operation
+		a = 1;
+		inc_wrapi(a, 0, 15);
+		assert(a == 2);
+
+		// not overflow yet
+		a = 14;
+		inc_wrapi(a, 0, 15);
+		assert(a == 15);
+
+		// overflow
+		a = 15;
+		inc_wrap(a, 0, 15);
+		assert(a == 0);
+	}
+
+
+	printf("fn: dec_wrap()\n");
+	{
+		// normal operation
+		a = 5;
+		dec_wrap(a, 0, 15);
+		assert(a == 4);
+
+		// underflow
+		a = 0;
+		dec_wrap(a, 0, 15);
+		assert(a == 14);
+	}
+
+
+	printf("fn: dec_wrapi()\n");
+	{
+		// normal operation
+		a = 5;
+		dec_wrapi(a, 0, 15);
+		assert(a == 4);
+
+		// underflow
+		a = 0;
+		dec_wrapi(a, 0, 15);
+		assert(a == 15);
+	}
+
+
+	printf("fn: sbi()\n");
+	{
+		a = 0;
+		sbi(a, 2);
+		assert(a == 0b100);
+	}
+
+
+	printf("fn: cbi()\n");
+	{
+		a = 0b11111;
+		cbi(a, 2);
+		assert(a == 0b11011);
+	}
+
+
+	printf("fn: read_bit()\n");
+	{
+		a = 0b101;
+		assert(read_bit(a, 0) == 1);
+		assert(read_bit(a, 1) == 0);
+		assert(read_bit(a, 2) == 1);
+	}
+
+
+	printf("fn: bit_is_high()\n");
+	{
+		a = 0b101;
+		assert(bit_is_high(a, 0) == 1);
+		assert(bit_is_high(a, 1) == 0);
+		assert(bit_is_high(a, 2) == 1);
+	}
+
+
+	printf("fn: bit_is_low()\n");
+	{
+		a = 0b101;
+		assert(bit_is_low(a, 0) == 0);
+		assert(bit_is_low(a, 1) == 1);
+		assert(bit_is_low(a, 2) == 0);
+	}
+
+
+	printf("fn: toggle_bit()\n");
+	{
+		a = 0;
+		toggle_bit(a, 2);
+		assert(a == 0b00100);
+		toggle_bit(a, 4);
+		assert(a == 0b10100);
+		toggle_bit(a, 4);
+		assert(a == 0b00100);
+	}
+
+	// pointer variants
+
+	int* b = &a;
+
+	printf("fn: sbi_p()\n");
+	{
+		*b = 0;
+		sbi_p(b, 2);
+		assert(*b == 0b100);
+	}
+
+
+	printf("fn: cbi_p()\n");
+	{
+		*b = 0b11111;
+		cbi_p(b, 2);
+		assert(*b == 0b11011);
+	}
+
+
+	printf("fn: read_bit_p()\n");
+	{
+		*b = 0b101;
+		assert(read_bit_p(b, 0) == 1);
+		assert(read_bit_p(b, 1) == 0);
+		assert(read_bit_p(b, 2) == 1);
+	}
+
+
+	printf("fn: bit_is_high_p()\n");
+	{
+		*b = 0b101;
+		assert(bit_is_high_p(b, 0) == 1);
+		assert(bit_is_high_p(b, 1) == 0);
+		assert(bit_is_high_p(b, 2) == 1);
+	}
+
+
+	printf("fn: bit_is_low_p()\n");
+	{
+		*b = 0b101;
+		assert(bit_is_low_p(b, 0) == 0);
+		assert(bit_is_low_p(b, 1) == 1);
+		assert(bit_is_low_p(b, 2) == 0);
+	}
+
+
+	printf("fn: toggle_bit_p()\n");
+	{
+		*b = 0;
+		toggle_bit_p(b, 2);
+		assert(*b == 0b00100);
+		toggle_bit_p(b, 4);
+		assert(*b == 0b10100);
+		toggle_bit_p(b, 4);
+		assert(*b == 0b00100);
+	}
+
+
+	// -- nibbles --
+
+	printf("fn: write_low_nibble()\n");
+	{
+		a = 0xAC;
+		write_low_nibble(a, 0x5); // shifted 4 left
+		assert(a == 0xA5);
+
+		a = 0xAB;
+		write_low_nibble(a, 0x65); // shifted 4 left, extra ignored
+		assert(a == 0xA5);
+	}
+
+
+	printf("fn: write_high_nibble()\n");
+	{
+		a = 0xAC;
+		write_high_nibble(a, 0x5); // shifted 4 left
+		assert(a == 0x5C);
+
+		a = 0xAB;
+		write_high_nibble(a, 0x65); // shifted 4 left, extra ignored
+		assert(a == 0x5B);
+	}
+
+
+	printf("fn: write_low_nibble_p()\n");
+	{
+		*b = 0xAC;
+		write_low_nibble_p(b, 0x5); // shifted 4 left
+		assert(*b == 0xA5);
+
+		*b = 0xAB;
+		write_low_nibble_p(b, 0x65); // shifted 4 left, extra ignored
+		assert(*b == 0xA5);
+	}
+
+
+	printf("fn: write_high_nibble_p()\n");
+	{
+		*b = 0xAC;
+		write_high_nibble_p(b, 0x5); // shifted 4 left
+		assert(*b == 0x5C);
+
+		*b = 0xAB;
+		write_high_nibble_p(b, 0x65); // shifted 4 left, extra ignored
+		assert(*b == 0x5B);
+	}
+
+
+	printf("fn: in_range()\n");
+	{
+		// regular
+		assert(in_range(10, 10, 15));
+		assert(in_range(14, 10, 15));
+		assert(in_range(13, 10, 15));
+		// under
+		assert(!in_range(9, 10, 15));
+		assert(!in_range(0, 10, 15));
+		// above
+		assert(!in_range(15, 10, 15));
+		assert(!in_range(99, 10, 15));
+
+		// swapped bounds
+
+		// regular
+		assert(in_range(10, 15, 10));
+		assert(in_range(14, 15, 10));
+		assert(in_range(13, 15, 10));
+		// under
+		assert(!in_range(9, 15, 10));
+		assert(!in_range(0, 15, 10));
+		// above
+		assert(!in_range(15, 15, 10));
+		assert(!in_range(99, 15, 10));
+	}
+
+
+	printf("fn: in_rangei()\n");
+	{
+		// regular
+		assert(in_rangei(10, 10, 15));
+		assert(in_rangei(15, 10, 15));
+		assert(in_rangei(13, 10, 15));
+		// under
+		assert(!in_rangei(9, 10, 15));
+		assert(!in_rangei(0, 10, 15));
+		// above
+		assert(!in_rangei(16, 10, 15));
+		assert(!in_rangei(99, 10, 15));
+
+		// -- swapped bounds --
+
+		// regular
+		assert(in_rangei(10, 15, 10));
+		assert(in_rangei(15, 15, 10));
+		assert(in_rangei(13, 15, 10));
+		// under
+		assert(!in_rangei(9, 15, 10));
+		assert(!in_rangei(0, 15, 10));
+		// above
+		assert(!in_rangei(16, 15, 10));
+		assert(!in_rangei(99, 15, 10));
+	}
+
+
+	printf("fn: in_range_wrap()\n");
+	{
+		// as regular range
+
+		// regular
+		assert(in_range_wrap(10, 10, 15));
+		assert(in_range_wrap(14, 10, 15));
+		assert(in_range_wrap(13, 10, 15));
+		// under
+		assert(!in_range_wrap(9, 10, 15));
+		assert(!in_range_wrap(0, 10, 15));
+		// above
+		assert(!in_range_wrap(15, 10, 15));
+		assert(!in_range_wrap(16, 10, 15));
+		assert(!in_range_wrap(99, 10, 15));
+
+		// with wrap (>= 15, < 10)
+
+		// regular
+		assert(!in_range_wrap(10, 15, 10));
+		assert(!in_range_wrap(14, 15, 10));
+		assert(!in_range_wrap(13, 15, 10));
+		// under
+		assert(in_range_wrap(9, 15, 10));
+		assert(in_range_wrap(0, 15, 10));
+		// above
+		assert(in_range_wrap(16, 15, 10));
+		assert(in_range_wrap(99, 15, 10));
+	}
+
+
+	printf("fn: in_range_wrapi()\n");
+	{
+		// as regular range
+
+		// regular
+		assert(in_range_wrapi(10, 10, 15));
+		assert(in_range_wrapi(15, 10, 15));
+		assert(in_range_wrapi(13, 10, 15));
+		// under
+		assert(!in_range_wrapi(9, 10, 15));
+		assert(!in_range_wrapi(0, 10, 15));
+		// above
+		assert(!in_range_wrapi(16, 10, 15));
+		assert(!in_range_wrapi(99, 10, 15));
+
+		// with wrap (>= 15, < 10)
+
+		// regular
+		assert(in_range_wrapi(10, 15, 10));
+		assert(!in_range_wrapi(14, 15, 10));
+		assert(!in_range_wrapi(13, 15, 10));
+		// under
+		assert(in_range_wrapi(10, 15, 10));
+		assert(in_range_wrapi(0, 15, 10));
+		// above
+		assert(in_range_wrapi(16, 15, 10));
+		assert(in_range_wrapi(99, 15, 10));
+	}
+
+	printf("== PASSED ==\n");
+}

lib_tests/test_loops_visual.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include "lib/loops.h"
+
+void main()
+{
+	repeat(5) printf("Five times!\n");
+	repeatx(500) printf(".");
+	printf("\n");
+	int i = 0;
+	until (i == 100) i++;
+
+	until (i == 0) {
+	  i--;
+	  printf("i = %d\n", i);
+	}
+
+	printf("\n");
+
+	loop(moo, 7) {
+	  printf("moo = %d\n", moo);
+	}
+}

lib_tests/test_yeolde.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include "lib/loops.h"
+#include "lib/yeolde.h"
+
+void main()
+commence
+	let number a be 0;
+	whilst (a under 13)
+	commence
+		raise (a);
+
+		when (a is 5)
+		then
+			printf("A is ugly 5\n");
+			replay;
+		cease;
+
+		choose (a)
+		commence
+			option 1:
+				printf("A is 1\n");
+				shatter;
+			option 2:
+				printf("A is 2\n");
+				shatter;
+			option 3:
+				printf("Neither 1 nor 2\n");
+		cease;
+	cease;
+cease