diff options
Diffstat (limited to 'src/display.cc')
| -rw-r--r-- | src/display.cc | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/display.cc b/src/display.cc new file mode 100644 index 0000000..dfe4c1f --- /dev/null +++ b/src/display.cc @@ -0,0 +1,236 @@ +/* + * Copyright (C) 2016 by Daniel Friesel + * + * License: You may use, redistribute and/or modify this file under the terms + * of either: + * * The GNU LGPL v3 (see COPYING and COPYING.LESSER), or + * * The 3-clause BSD License (see COPYING.BSD) + * + */ + +#include <avr/io.h> +#include <avr/interrupt.h> +#include <avr/pgmspace.h> +#include <stdlib.h> + +#include "display.h" +#include "font.h" +#include "storage.h" + +Display display; + +Display::Display() +{ + char_pos = -1; +} + +void Display::disable() +{ + TIMSK0 &= ~_BV(TOIE0); + PORTB = 0; + PORTD = 0; +} + +void Display::enable() +{ + // Ports B and D drive the dot matrix display -> set all as output + DDRB = 0xff; + DDRD = 0xff; + + // Enable 8bit counter with prescaler=8 (-> timer frequency = 1MHz) + TCCR0A = _BV(CS01); + // raise timer interrupt on counter overflow (-> interrupt frequency = ~4kHz) + TIMSK0 = _BV(TOIE0); +} + +void Display::multiplex() +{ + /* + * To avoid flickering, do not put any code (or expensive index + * calculations) between the following three lines. + */ + PORTB = 0; + PORTD = disp_buf[active_col]; + PORTB = _BV(active_col); + + if (++active_col == 8) { + active_col = 0; + if (++update_cnt == update_threshold) { + update_cnt = 0; + need_update = 1; + } + } +} + +void Display::update() { + uint8_t i, glyph_len; + uint8_t *glyph_addr; + if (need_update) { + need_update = 0; + + if (status == RUNNING) { + if (current_anim->type == AnimationType::TEXT) { + + /* + * Scroll display contents to the left/right + */ + if (current_anim->direction == 0) { + for (i = 0; i < 7; i++) { + disp_buf[i] = disp_buf[i+1]; + } + } else if (current_anim->direction == 1) { + for (i = 7; i > 0; i--) { + disp_buf[i] = disp_buf[i-1]; + } + } + + /* + * Load current character + */ + glyph_addr = (uint8_t *)pgm_read_ptr(&font[current_anim->data[str_pos]]); + glyph_len = pgm_read_byte(&glyph_addr[0]); + char_pos++; + + if (char_pos > glyph_len) { + char_pos = 0; + if (current_anim->direction == 0) + str_pos++; + else + str_pos--; // may underflow, but that's okay + } + + /* + * Append one character column (or whitespace if we are + * between two characters) + */ + if (current_anim->direction == 0) { + if (char_pos == 0) { + disp_buf[7] = 0xff; // whitespace + } else { + disp_buf[7] = ~pgm_read_byte(&glyph_addr[char_pos]); + } + } else { + if (char_pos == 0) { + disp_buf[0] = 0xff; // whitespace + } else { + disp_buf[0] = ~pgm_read_byte(&glyph_addr[glyph_len - char_pos + 1]); + } + } + + } else if (current_anim->type == AnimationType::FRAMES) { + for (i = 0; i < 8; i++) { + disp_buf[i] = ~current_anim->data[str_pos+i]; + } + str_pos += 8; + } + + if (current_anim->direction == 0) { + /* + * Check whether we reached the end of the pattern + * (that is, we're in the last chunk and reached the + * remaining pattern length) + */ + if ((str_chunk == ((current_anim->length - 1) / 128)) + && (str_pos > ((current_anim->length - 1) % 128))) { + str_chunk = 0; + str_pos = 0; + if (current_anim->delay > 0) { + status = PAUSED; + update_threshold = 244; + } + if (current_anim->length > 128) { + storage.loadChunk(str_chunk, current_anim->data); + } + /* + * Otherwise, check whether the pattern is split into + * several chunks and we reached the end of the chunk + * kept in current_anim->data + */ + } else if ((current_anim->length > 128) && (str_pos >= 128)) { + str_pos = 0; + str_chunk++; + storage.loadChunk(str_chunk, current_anim->data); + } + } else { + /* + * In this branch we keep doing str_pos--, so check for + * underflow + */ + if (str_pos >= 128) { + /* + * Check whether we reached the end of the pattern + * (and whether we need to load a new chunk) + */ + if (str_chunk == 0) { + if (current_anim->length > 128) { + str_chunk = (current_anim->length - 1) / 128; + storage.loadChunk(str_chunk, current_anim->data); + } + if (current_anim->delay > 0) { + str_pos = 0; + status = PAUSED; + update_threshold = 244; + } else { + str_pos = (current_anim->length - 1) % 128; + } + /* + * Otherwise, we reached the end of the active chunk + */ + } else { + str_chunk--; + storage.loadChunk(str_chunk, current_anim->data); + str_pos = 127; + } + } + } + } else if (status == PAUSED) { + str_pos++; + if (str_pos >= current_anim->delay) { + if (current_anim->direction == 0) + str_pos = 0; + else if (current_anim->length <= 128) + str_pos = current_anim->length - 1; + else + str_pos = (current_anim->length - 1) % 128; + status = RUNNING; + update_threshold = current_anim->speed; + } + } + } +} + +void Display::reset() +{ + for (uint8_t i = 0; i < 8; i++) + disp_buf[i] = 0xff; + update_cnt = 0; + str_pos = 0; + str_chunk = 0; + char_pos = -1; + need_update = 1; + status = RUNNING; +} + +void Display::show(animation_t *anim) +{ + current_anim = anim; + reset(); + update_threshold = current_anim->speed; + if (current_anim->direction == 1) { + if (current_anim->length > 128) { + str_chunk = (current_anim->length - 1) / 128; + storage.loadChunk(str_chunk, current_anim->data); + } + str_pos = (current_anim->length - 1) % 128; + } +} + +/* + * Current configuration: + * One interrupt per 256 microseconds. The whole display is refreshed every + * 2048us, giving a refresh rate of ~500Hz + */ +ISR(TIMER0_OVF_vect) +{ + display.multiplex(); +} |