Merge branch 'develop' -- breaking changes 2022-05-28.

2 files changed, 504 insertions, 0 deletions

diff --git a/drivers/lcd/hd44780.c b/drivers/lcd/hd44780.c
new file mode 100644
index 0000000000..c988ebe56c
--- /dev/null
+++ b/drivers/lcd/hd44780.c
@@ -0,0 +1,284 @@
+/*
+Copyright 2022
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "hd44780.h"
+#include "gpio.h"
+#include "progmem.h"
+#include "wait.h"
+
+#ifndef HD44780_DATA_PINS
+#    error hd44780: no data pins defined!
+#endif
+
+#ifndef HD44780_RS_PIN
+#    error hd44780: no RS pin defined!
+#endif
+
+#ifndef HD44780_RW_PIN
+#    error hd44780: no R/W pin defined!
+#endif
+
+#ifndef HD44780_E_PIN
+#    error hd44780: no E pin defined!
+#endif
+
+static const pin_t data_pins[4] = HD44780_DATA_PINS;
+
+#ifndef HD44780_DISPLAY_COLS
+#    define HD44780_DISPLAY_COLS 16
+#endif
+
+#ifndef HD44780_DISPLAY_LINES
+#    define HD44780_DISPLAY_LINES 2
+#endif
+
+#ifndef HD44780_DDRAM_LINE0_ADDR
+#    define HD44780_DDRAM_LINE0_ADDR 0x00
+#endif
+#ifndef HD44780_DDRAM_LINE1_ADDR
+#    define HD44780_DDRAM_LINE1_ADDR 0x40
+#endif
+
+#define HD44780_INIT_DELAY_MS 16
+#define HD44780_ENABLE_DELAY_US 1
+
+static void hd44780_latch(void) {
+    writePinHigh(HD44780_E_PIN);
+    wait_us(HD44780_ENABLE_DELAY_US);
+    writePinLow(HD44780_E_PIN);
+}
+
+void hd44780_write(uint8_t data, bool isData) {
+    writePin(HD44780_RS_PIN, isData);
+    writePinLow(HD44780_RW_PIN);
+
+    for (int i = 0; i < 4; i++) {
+        setPinOutput(data_pins[i]);
+    }
+
+    // Write high nibble
+    for (int i = 0; i < 4; i++) {
+        writePin(data_pins[i], (data >> 4) & (1 << i));
+    }
+    hd44780_latch();
+
+    // Write low nibble
+    for (int i = 0; i < 4; i++) {
+        writePin(data_pins[i], data & (1 << i));
+    }
+    hd44780_latch();
+
+    for (int i = 0; i < 4; i++) {
+        writePinHigh(data_pins[i]);
+    }
+}
+
+uint8_t hd44780_read(bool isData) {
+    uint8_t data = 0;
+
+    writePin(HD44780_RS_PIN, isData);
+    writePinHigh(HD44780_RW_PIN);
+
+    for (int i = 0; i < 4; i++) {
+        setPinInput(data_pins[i]);
+    }
+
+    writePinHigh(HD44780_E_PIN);
+    wait_us(HD44780_ENABLE_DELAY_US);
+
+    // Read high nibble
+    for (int i = 0; i < 4; i++) {
+        data |= (readPin(data_pins[i]) << i);
+    }
+
+    data <<= 4;
+
+    writePinLow(HD44780_E_PIN);
+    wait_us(HD44780_ENABLE_DELAY_US);
+    writePinHigh(HD44780_E_PIN);
+    wait_us(HD44780_ENABLE_DELAY_US);
+
+    // Read low nibble
+    for (int i = 0; i < 4; i++) {
+        data |= (readPin(data_pins[i]) << i);
+    }
+
+    writePinLow(HD44780_E_PIN);
+
+    return data;
+}
+
+bool hd44780_busy(void) {
+    return hd44780_read(false) & HD44780_BUSY_FLAG;
+}
+
+void hd44780_command(uint8_t command) {
+    while (hd44780_busy())
+        ;
+    hd44780_write(command, false);
+}
+
+void hd44780_data(uint8_t data) {
+    while (hd44780_busy())
+        ;
+    hd44780_write(data, true);
+}
+
+void hd44780_clear(void) {
+    hd44780_command(HD44780_CMD_CLEAR_DISPLAY);
+}
+
+void hd44780_home(void) {
+    hd44780_command(HD44780_CMD_RETURN_HOME);
+}
+
+void hd44780_on(bool cursor, bool blink) {
+    if (cursor) {
+        if (blink) {
+            hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR | HD44780_DISPLAY_BLINK);
+        } else {
+            hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON | HD44780_DISPLAY_CURSOR);
+        }
+    } else {
+        hd44780_command(HD44780_CMD_DISPLAY | HD44780_DISPLAY_ON);
+    }
+}
+
+void hd44780_off() {
+    hd44780_command(HD44780_CMD_DISPLAY);
+}
+
+void hd44780_set_cgram_address(uint8_t address) {
+    hd44780_command(HD44780_CMD_SET_CGRAM_ADDRESS + (address & 0x3F));
+}
+
+void hd44780_set_ddram_address(uint8_t address) {
+    hd44780_command(HD44780_CMD_SET_DDRAM_ADDRESS + (address & 0x7F));
+}
+
+void hd44780_init(bool cursor, bool blink) {
+    setPinOutput(HD44780_RS_PIN);
+    setPinOutput(HD44780_RW_PIN);
+    setPinOutput(HD44780_E_PIN);
+
+    for (int i = 0; i < 4; i++) {
+        setPinOutput(data_pins[i]);
+    }
+
+    wait_ms(HD44780_INIT_DELAY_MS);
+
+    // Manually configure for 4-bit mode - can't use hd44780_command() yet
+    // HD44780U datasheet, Fig. 24 (p46)
+    writePinHigh(data_pins[0]); // Function set
+    writePinHigh(data_pins[1]); // DL = 1
+    hd44780_latch();
+    wait_ms(5);
+    // Send again
+    hd44780_latch();
+    wait_us(64);
+    // And again (?)
+    hd44780_latch();
+    wait_us(64);
+
+    writePinLow(data_pins[0]); // DL = 0
+    hd44780_latch();
+    wait_us(64);
+
+#if HD44780_DISPLAY_LINES == 1
+    hd44780_command(HD44780_CMD_FUNCTION); // 4 bit, 1 line, 5x8 dots
+#else
+    hd44780_command(HD44780_CMD_FUNCTION | HD44780_FUNCTION_2_LINES); // 4 bit, 2 lines, 5x8 dots
+#endif
+    hd44780_on(cursor, blink);
+    hd44780_clear();
+    hd44780_home();
+    hd44780_command(HD44780_CMD_ENTRY_MODE | HD44780_ENTRY_MODE_INC);
+}
+
+void hd44780_set_cursor(uint8_t col, uint8_t line) {
+    register uint8_t address = col;
+
+#if HD44780_DISPLAY_LINES == 1
+    address += HD44780_DDRAM_LINE0_ADDR;
+#elif HD44780_DISPLAY_LINES == 2
+    if (line == 0) {
+        address += HD44780_DDRAM_LINE0_ADDR;
+    } else {
+        address += HD44780_DDRAM_LINE1_ADDR;
+    }
+#endif
+
+    hd44780_set_ddram_address(address);
+}
+
+void hd44780_define_char(uint8_t index, uint8_t *data) {
+    hd44780_set_cgram_address((index & 0x7) << 3);
+    for (uint8_t i = 0; i < 8; i++) {
+        hd44780_data(data[i]);
+    }
+}
+
+void hd44780_putc(char c) {
+    while (hd44780_busy())
+        ;
+    uint8_t current_position = hd44780_read(false);
+
+    if (c == '\n') {
+        hd44780_set_cursor(0, current_position < HD44780_DDRAM_LINE1_ADDR ? 1 : 0);
+    } else {
+#if defined(HD44780_WRAP_LINES)
+#    if HD44780_DISPLAY_LINES == 1
+        if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
+            // Go to start of line
+            hd44780_set_cursor(0, 0);
+        }
+#    elif HD44780_DISPLAY_LINES == 2
+        if (current_position == HD44780_DDRAM_LINE0_ADDR + HD44780_DISPLAY_COLS) {
+            // Go to start of second line
+            hd44780_set_cursor(0, 1);
+        } else if (current_position == HD44780_DDRAM_LINE1_ADDR + HD44780_DISPLAY_COLS) {
+            // Go to start of first line
+            hd44780_set_cursor(0, 0);
+        }
+#    endif
+#endif
+        hd44780_data(c);
+    }
+}
+
+void hd44780_puts(const char *s) {
+    register char c;
+    while ((c = *s++)) {
+        hd44780_putc(c);
+    }
+}
+
+#if defined(__AVR__)
+void hd44780_define_char_P(uint8_t index, const uint8_t *data) {
+    hd44780_set_cgram_address(index << 3);
+    for (uint8_t i = 0; i < 8; i++) {
+        hd44780_data(pgm_read_byte(data++));
+    }
+}
+
+void hd44780_puts_P(const char *s) {
+    register char c;
+    while ((c = pgm_read_byte(s++))) {
+        hd44780_putc(c);
+    }
+}
+#endif
diff --git a/drivers/lcd/hd44780.h b/drivers/lcd/hd44780.h
new file mode 100644
index 0000000000..9e43339344
--- /dev/null
+++ b/drivers/lcd/hd44780.h
@@ -0,0 +1,220 @@
+/*
+Copyright 2022
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/**
+ * \defgroup hd44780
+ *
+ * HD44780 Character LCD Driver
+ * \{
+ */
+
+/*
+ * HD44780 instructions
+ * https://www.sparkfun.com/datasheets/LCD/HD44780.pdf
+ * Table 6 (p24)
+ */
+// Clear display
+#define HD44780_CMD_CLEAR_DISPLAY 0x01
+// Return home
+#define HD44780_CMD_RETURN_HOME 0x02
+// Entry mode set
+#define HD44780_CMD_ENTRY_MODE 0x04
+#define HD44780_ENTRY_MODE_INC 0x02   // I/D
+#define HD44780_ENTRY_MODE_SHIFT 0x01 // S
+// Display on/off control
+#define HD44780_CMD_DISPLAY 0x08
+#define HD44780_DISPLAY_ON 0x04     // D
+#define HD44780_DISPLAY_CURSOR 0x02 // C
+#define HD44780_DISPLAY_BLINK 0x01  // B
+// Cursor or display shift
+#define HD44780_CMD_MOVE 0x10
+#define HD44780_MOVE_DISPLAY 0x08 // S/C
+#define HD44780_MOVE_RIGHT 0x04   // R/L
+// Function set
+#define HD44780_CMD_FUNCTION 0x20
+#define HD44780_FUNCTION_8_BIT 0x10     // DL
+#define HD44780_FUNCTION_2_LINES 0x08   // N
+#define HD44780_FUNCTION_5X10_DOTS 0x04 // F
+// Set CGRAM address
+#define HD44780_CMD_SET_CGRAM_ADDRESS 0x40
+// Set DDRAM address
+#define HD44780_CMD_SET_DDRAM_ADDRESS 0x80
+
+// Bitmask for busy flag when reading
+#define HD44780_BUSY_FLAG 0x80
+
+/**
+ * \brief Write a byte to the display.
+ *
+ * \param data The byte to send to the display.
+ * \param isData Whether the byte is an instruction or character data.
+ */
+void hd44780_write(uint8_t data, bool isData);
+
+/**
+ * \brief Read a byte from the display.
+ *
+ * \param isData Whether to read the current cursor position, or the character at the cursor.
+ *
+ * \return If `isData` is `true`, the returned byte will be the character at the current DDRAM address. Otherwise, it will be the current DDRAM address and the busy flag.
+ */
+uint8_t hd44780_read(bool isData);
+
+/**
+ * \brief Indicates whether the display is currently processing, and cannot accept instructions.
+ *
+ * \return `true` if the display is busy.
+ */
+bool hd44780_busy(void);
+
+/**
+ * \brief Send a command to the display. Refer to the datasheet for the valid commands.
+ *
+ * This function waits for the display to clear the busy flag before sending the command.
+ *
+ * \param command The command to send.
+ */
+void hd44780_command(uint8_t command);
+
+/**
+ * \brief Send a byte of data to the display.
+ *
+ * This function waits for the display to clear the busy flag before sending the data.
+ *
+ * \param data The byte of data to send.
+ */
+void hd44780_data(uint8_t data);
+
+/**
+ * \brief Clear the display.
+ *
+ * This function is called on init.
+ */
+void hd44780_clear(void);
+
+/**
+ * \brief Move the cursor to the home position.
+ *
+ * This function is called on init.
+ */
+void hd44780_home(void);
+
+/**
+ * \brief Turn the display on, and/or set the cursor position.
+ *
+ * This function is called on init.
+ *
+ * \param cursor Whether to show the cursor.
+ * \param blink Whether to blink the cursor, if shown.
+ */
+void hd44780_on(bool cursor, bool blink);
+
+/**
+ * \brief Turn the display off.
+ */
+void hd44780_off(void);
+
+/**
+ * \brief Set the CGRAM address.
+ *
+ * This function is used when defining custom characters.
+ *
+ * \param address The CGRAM address to move to, from `0x00` to `0x3F`.
+ */
+void hd44780_set_cgram_address(uint8_t address);
+
+/**
+ * \brief Set the DDRAM address.
+ *
+ * This function is used when printing characters to the display, and setting the cursor.
+ *
+ * \param address The DDRAM address to move to, from `0x00` to `0x7F`.
+ */
+void hd44780_set_ddram_address(uint8_t address);
+
+/**
+ * \brief Initialize the display.
+ *
+ * This function should be called only once, before any of the other functions can be called.
+ *
+ * \param cursor Whether to show the cursor.
+ * \param blink Whether to blink the cursor, if shown.
+ */
+void hd44780_init(bool cursor, bool blink);
+
+/**
+ * \brief Move the cursor to the specified position on the display.
+ *
+ * \param col The column number to move to, from 0 to 15 on 16x2 displays.
+ * \param line The line number to move to, either 0 or 1 on 16x2 displays.
+ */
+void hd44780_set_cursor(uint8_t col, uint8_t line);
+
+/**
+ * \brief Define a custom character.
+ *
+ * \param index The index of the custom character to define, from 0 to 7.
+ * \param data An array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column.
+ */
+void hd44780_define_char(uint8_t index, uint8_t *data);
+
+/**
+ * \brief Print a character to the display. The newline character will move the cursor to the start of the next line.
+ *
+ * The exact character shown may depend on the ROM code of your particular display - refer to the datasheet for the full character set.
+ *
+ * \param c The character to print.
+ */
+void hd44780_putc(char c);
+
+/**
+ * \brief Print a string of characters to the display.
+ *
+ * \param s The string to print.
+ */
+void hd44780_puts(const char *s);
+
+#if defined(__AVR__) || defined(__DOXYGEN__)
+/**
+ * \brief Define a custom character from PROGMEM.
+ *
+ * On ARM devices, this function is simply an alias of hd44780_define_char().
+ *
+ * \param index The index of the custom character to define, from 0 to 7.
+ * \param data A PROGMEM array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column.
+ */
+void hd44780_define_char_P(uint8_t index, const uint8_t *data);
+
+/**
+ * \brief Print a string of characters from PROGMEM to the display.
+ *
+ * On ARM devices, this function is simply an alias of hd44780_puts().
+ *
+ * \param s The PROGMEM string to print.
+ */
+void hd44780_puts_P(const char *s);
+#else
+#    define hd44780_define_char_P(index, data) hd44780_define_char(index, data)
+#    define hd44780_puts_P(s) hd44780_puts(s)
+#endif
+
+/** \} */