qmk-firmware/quantum/process_keycode/process_printer_bb.c

/* Copyright 2016 Jack Humbert
 *
 * 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 "process_printer.h"
#include "action_util.h"

bool    printing_enabled = false;
uint8_t character_shift  = 0;

#define SERIAL_PIN_DDR DDRD
#define SERIAL_PIN_PORT PORTD
#define SERIAL_PIN_MASK _BV(PD3)
#define SERIAL_DELAY 52

inline static void serial_delay(void) {
    _delay_us(SERIAL_DELAY);
}

inline static void serial_high(void) {
    SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
}

inline static void serial_low(void) {
    SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;
}

inline static void serial_output(void) {
    SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
}

void enable_printing() {
    printing_enabled = true;
    serial_output();
    serial_high();
}

void disable_printing() {
    printing_enabled = false;
}

uint8_t shifted_numbers[10] = {0x21, 0x40, 0x23, 0x24, 0x25, 0x5E, 0x26, 0x2A, 0x28, 0x29};

// uint8_t keycode_to_ascii[0xFF][2];

// keycode_to_ascii[KC_MINUS] = {0x2D, 0x5F};

void print_char(char c) {
    uint8_t b = 8;
    serial_output();
    while (b--) {
        if (c & (1 << b)) {
            serial_high();
        } else {
            serial_low();
        }
        serial_delay();
    }
}

void print_string(char c[]) {
    for (uint8_t i = 0; i < strlen(c); i++)
        print_char(c[i]);
}

bool process_printer(uint16_t keycode, keyrecord_t *record) {
    if (keycode == PRINT_ON) {
        enable_printing();
        return false;
    }
    if (keycode == PRINT_OFF) {
        disable_printing();
        return false;
    }

    if (printing_enabled) {
        switch (keycode) {
            case KC_EXLM ... KC_RPRN:
            case KC_UNDS:
            case KC_PLUS:
            case KC_LCBR:
            case KC_RCBR:
            case KC_PIPE:
            case KC_TILD:
                keycode &= 0xFF;
            case KC_LEFT_SHIFT:
            case KC_RIGHT_SHIFT:
                if (record->event.pressed) {
                    character_shift++;
                } else {
                    character_shift--;
                }
                return false;
                break;
        }

        switch (keycode) {
            case KC_F1:
                if (record->event.pressed) {
                    print_string("This is a line of text!\n\n\n");
                }
                return false;
            case KC_ESCAPE:
                if (record->event.pressed) {
                    print_char(0x1B);
                }
                return false;
                break;
            case KC_SPACE:
                if (record->event.pressed) {
                    print_char(0x20);
                }
                return false;
                break;
            case KC_A ... KC_Z:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x41 + (keycode - KC_A));
                    } else {
                        print_char(0x61 + (keycode - KC_A));
                    }
                }
                return false;
                break;
            case KC_1 ... KC_0:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(shifted_numbers[keycode - KC_1]);
                    } else {
                        print_char(0x30 + ((keycode - KC_1 + 1) % 10));
                    }
                }
                return false;
                break;
            case KC_ENTER:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x0C);
                    } else {
                        print_char(0x0A);
                    }
                }
                return false;
                break;
            case KC_BACKSPACE:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x18);
                    } else {
                        print_char(0x1A);
                    }
                }
                return false;
                break;
            case KC_DOT:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x3E);
                    } else {
                        print_char(0x2E);
                    }
                }
                return false;
                break;
            case KC_COMMA:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x3C);
                    } else {
                        print_char(0x2C);
                    }
                }
                return false;
                break;
            case KC_SLASH:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x3F);
                    } else {
                        print_char(0x2F);
                    }
                }
                return false;
                break;
            case KC_QUOTE:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x22);
                    } else {
                        print_char(0x27);
                    }
                }
                return false;
                break;
            case KC_GRAVE:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x7E);
                    } else {
                        print_char(0x60);
                    }
                }
                return false;
                break;
            case KC_MINUS:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x5F);
                    } else {
                        print_char(0x2D);
                    }
                }
                return false;
                break;
            case KC_EQUAL:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x2B);
                    } else {
                        print_char(0x3D);
                    }
                }
                return false;
                break;
            case KC_LEFT_BRACKET:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x7B);
                    } else {
                        print_char(0x5B);
                    }
                }
                return false;
                break;
            case KC_RIGHT_BRACKET:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x7D);
                    } else {
                        print_char(0x5D);
                    }
                }
                return false;
                break;
            case KC_BACKSLASH:
                if (record->event.pressed) {
                    if (character_shift) {
                        print_char(0x7C);
                    } else {
                        print_char(0x5C);
                    }
                }
                return false;
                break;
        }
    }
    return true;
}