eink/eink.hpp

#pragma once

#include <stdint.h>

#include <avr/pgmspace.h>

#include "../clock.hpp"
#include "../io/io.hpp"
#include "../util/util.hpp"

namespace eink {

template <uint16_t Width, uint16_t Height, typename Spi, io::P RstPin, io::P DcPin, io::P BusyPin>
class Eink {
	struct Cmd {
		static constexpr auto SW_RESET = uint8_t{0x12};
		static constexpr auto DRIVER_OUTPUT_CONTROL = uint8_t{0x01};
		static constexpr auto DATA_ENTRY_MODE = uint8_t{0x11};
		static constexpr auto SET_RAM_X_ADDR_POSITIONS = uint8_t{0x44};
		static constexpr auto SET_RAM_Y_ADDR_POSITIONS = uint8_t{0x45};
		static constexpr auto BORDER_WAVEFORM_CONTROL = uint8_t{0x3C};
		static constexpr auto READ_TEMPERATURE_SENSOR = uint8_t{0x18};
		static constexpr auto SET_RAM_X_ADDR = uint8_t{0x4E};
		static constexpr auto SET_RAM_Y_ADDR = uint8_t{0x4F};
		static constexpr auto WRITE_RAM_BLACK = uint8_t{0x24};
		static constexpr auto WRITE_RAM_RED = uint8_t{0x26};
		static constexpr auto DISPLAY_UPDATE_CONTROL_2 = uint8_t{0x22};
		static constexpr auto UPDATE_DISPLAY = uint8_t{0x20};
		static constexpr auto DEEP_SLEEP_MODE = uint8_t{0x10};
	};

	static io::Pin<RstPin> m_rst;
	static io::Pin<DcPin> m_dc;
	static io::Pin<BusyPin> m_bsy;

  public:
	static void init()
	{
		m_rst.dir(io::Dir::OUT);
		m_dc.dir(io::Dir::OUT);
		m_bsy.dir(io::Dir::IN);
		Spi::init();

		reset();

		waitUntilIdle();
		sendCommand(Cmd::SW_RESET);
		waitUntilIdle();

		sendCommand(Cmd::DRIVER_OUTPUT_CONTROL);
		sendData(0xC7);
		sendData(0x00);
		sendData(0x01);

		sendCommand(Cmd::DATA_ENTRY_MODE);
		sendData(0x02);

		sendCommand(Cmd::SET_RAM_X_ADDR_POSITIONS);
		sendData(Width / 8 - 1);
		sendData(0x00);

		sendCommand(Cmd::SET_RAM_Y_ADDR_POSITIONS);
		sendData(0x00);
		sendData(0x00);
		sendData(Height - 1);
		sendData(0x00);

		sendCommand(Cmd::BORDER_WAVEFORM_CONTROL);
		sendData(0x05);

		sendCommand(Cmd::READ_TEMPERATURE_SENSOR);
		sendData(0x80);

		sendCommand(Cmd::SET_RAM_X_ADDR);
		sendData(Width / 8 - 1);

		sendCommand(Cmd::SET_RAM_Y_ADDR);
		sendData(0x00);
		sendData(0x00);

		waitUntilIdle();
	}

	static void sendCommand(const uint8_t command)
	{
		m_dc = false;
		spiTransfer(command);
	}

	static void sendData(const uint8_t data)
	{
		m_dc = true;
		spiTransfer(data);
	}

	static void waitUntilIdle()
	{
		while (m_bsy) {
			_delay_ms(100);
		}
	}

	static void reset()
	{
		m_rst = true;
		_delay_ms(200);
		m_rst = false;
		_delay_ms(10);
		m_rst = true;
		_delay_ms(200);
	}

	template <typename Image>
	static void draw(const Image &image)
	{
		constexpr auto BLOCK_SIZE = 5;

		enum class Color : uint8_t {
			BLACK = 0b00,
			WHITE = 0b01,
			RED = 0b10,
			ERROR = 0b11,
		};

		class Block {
		  public:
			inline Color &operator[](const size_t idx)
			{
				return data[idx];
			}

			inline const Color &operator[](const size_t idx) const
			{
				return data[idx];
			}

		  private:
			Color data[BLOCK_SIZE];
		};

		constexpr auto lookup = [](uint8_t bits) {
			auto block = Block{};
			for_constexpr(
			    [&](const auto idx) {
				    block[idx.value] = static_cast<Color>(bits % 3);
				    bits /= 3;
			    },
			    util::make_index_sequence<BLOCK_SIZE>{});
			return block;
		};

		constexpr auto sendImageChannel = [lookup](const auto command, const auto image) {
			sendCommand(command);
			auto buffer = uint8_t{0};
			auto bufferPos = uint8_t{0};
			for (auto i = uint16_t{0}; i < Width * Height / BLOCK_SIZE; i++) {
				const auto block = lookup(pgm_read_byte(&image[i]));
				for (auto p = uint8_t{0}; p < BLOCK_SIZE; ++p) {
					const auto pixel = uint8_t{(command == Cmd::WRITE_RAM_BLACK) ? (block[p] != Color::BLACK)
					                                                             : (block[p] == Color::RED)};
					buffer |= pixel << (7 - bufferPos++);
					if (bufferPos == 8) {
						sendData(buffer);
						buffer = 0;
						bufferPos = 0;
					}
				}
			}
		};

		sendImageChannel(Cmd::WRITE_RAM_BLACK, image.data());
		sendImageChannel(Cmd::WRITE_RAM_RED, image.data());

		sendCommand(Cmd::DISPLAY_UPDATE_CONTROL_2);
		sendData(0xF7);
		sendCommand(Cmd::UPDATE_DISPLAY);
		waitUntilIdle();
	}

	static void clear()
	{
		sendCommand(Cmd::WRITE_RAM_BLACK);
		for (auto i = uint16_t{0}; i < Width * Height / 8; i++) {
			sendData(0xff);
		}
		sendCommand(Cmd::WRITE_RAM_RED);
		for (auto i = uint16_t{0}; i < Width * Height / 8; i++) {
			sendData(0x00);
		}

		sendCommand(Cmd::DISPLAY_UPDATE_CONTROL_2);
		sendData(0xF7);
		sendCommand(Cmd::UPDATE_DISPLAY);
		waitUntilIdle();
	}

	static void sleep()
	{
		sendCommand(Cmd::DEEP_SLEEP_MODE);
		sendData(0x01);
		_delay_ms(100);
	}

	static void spiTransfer(const uint8_t data)
	{
		Spi::select(true);
		Spi::transfer(data);
		Spi::select(false);
	}
};

} // namespace eink