98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
#include "lcd.h"
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// commands
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constexpr int LCD_CLEARDISPLAY = 0x01;
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constexpr int LCD_RETURNHOME = 0x02;
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constexpr int LCD_ENTRYMODESET = 0x04;
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constexpr int LCD_DISPLAYCONTROL = 0x08;
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constexpr int LCD_CURSORSHIFT = 0x10;
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constexpr int LCD_FUNCTIONSET = 0x20;
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constexpr int LCD_SETCGRAMADDR = 0x40;
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constexpr int LCD_SETDDRAMADDR = 0x80;
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// flags for display entry mode
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constexpr int LCD_ENTRYSHIFTINCREMENT = 0x01;
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constexpr int LCD_ENTRYLEFT = 0x02;
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// flags for display and cursor control
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constexpr int LCD_BLINKON = 0x01;
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constexpr int LCD_CURSORON = 0x02;
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constexpr int LCD_DISPLAYON = 0x04;
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// flags for function set
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constexpr int LCD_5x10DOTS = 0x04;
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constexpr int LCD_2LINE = 0x08;
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constexpr int LCD_8BITMODE = 0x10;
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constexpr int LCD_BACKLIGHT = 0x08;
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constexpr int LCD_ENABLE_BIT = 0x04;
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LCD::LCD(i2c_inst_t *i2c, const uint gpio_sda, const uint gpio_scl,
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const uint8_t i2c_addr, uint8_t num_cols, uint8_t num_lines)
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: i2c{i2c}, i2c_addr{i2c_addr}, num_cols{num_cols}, num_lines{num_lines} {
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i2c_init(i2c1, 100 * 1000);
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gpio_set_function(gpio_sda, GPIO_FUNC_I2C);
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gpio_set_function(gpio_scl, GPIO_FUNC_I2C);
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gpio_pull_up(gpio_sda);
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gpio_pull_up(gpio_scl);
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sendByte(0x03, Mode::COMMAND);
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sendByte(0x03, Mode::COMMAND);
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sendByte(0x03, Mode::COMMAND);
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sendByte(0x02, Mode::COMMAND);
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sendByte(LCD_ENTRYMODESET | LCD_ENTRYLEFT, Mode::COMMAND);
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sendByte(LCD_FUNCTIONSET | LCD_2LINE, Mode::COMMAND);
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sendByte(LCD_DISPLAYCONTROL | LCD_DISPLAYON, Mode::COMMAND);
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clear();
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}
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// go to location on LCD
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void LCD::setCursor(int line, int position) {
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int val = (line == 0) ? 0x80 + position : 0xC0 + position;
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sendByte(val, Mode::COMMAND);
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cursor_x = line;
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cursor_y = position;
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}
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void LCD::sendChar(char val) { sendByte(val, Mode::CHARACTER); }
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void LCD::sendString(const std::string &str) {
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for (const char &c : str) {
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if (c == '\n') {
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cursor_y++;
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setCursor(cursor_y, 0);
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} else {
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sendChar(c);
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cursor_x++;
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}
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}
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}
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void LCD::clear() { sendByte(LCD_CLEARDISPLAY, Mode::COMMAND); }
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void LCD::i2cWriteByte(uint8_t val) {
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i2c_write_blocking(i2c, i2c_addr, &val, 1, false);
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}
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void LCD::toggleEnable(uint8_t val) {
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// Toggle enable pin on LCD display
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// We cannot do this too quickly or things don't work
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constexpr uint64_t DELAY_US = 600;
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sleep_us(DELAY_US);
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i2cWriteByte(val | LCD_ENABLE_BIT);
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sleep_us(DELAY_US);
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i2cWriteByte(val & ~LCD_ENABLE_BIT);
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sleep_us(DELAY_US);
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}
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// The display is sent a byte as two separate nibble transfers
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void LCD::sendByte(uint8_t val, Mode mode) {
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uint8_t high = static_cast<int>(mode) | (val & 0xF0) | LCD_BACKLIGHT;
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uint8_t low = static_cast<int>(mode) | ((val << 4) & 0xF0) | LCD_BACKLIGHT;
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i2cWriteByte(high);
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toggleEnable(high);
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i2cWriteByte(low);
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toggleEnable(low);
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}
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