115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
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/** \file
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\brief Code specific to the SSD1306 display.
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*/
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#include "display_ssd1306.h"
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#ifdef DISPLAY_TYPE_SSD1306
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#include "displaybus.h"
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#include "font.h"
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static const uint8_t PROGMEM init_sequence[] = {
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0x00, // Command marker.
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0xAE, // Display off.
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0xD5, 0x80, // Display clock divider (reset).
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0xA8, 0x1F, // 1/32 duty.
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0x40 | 0x00, // Start line (reset).
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0x20, 0x02, // Page addressing mode (reset).
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0x22, 0x00, 0x03, // Start and end page in horiz./vert. addressing mode[1].
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0x21, 0x00, 0x7F, // Start and end column in horiz./vert. addressing mode.
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0xA0 | 0x00, // No segment remap (reset).
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0xC0 | 0x00, // Normal com pins mapping (reset).
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0xDA, 0x02, // Sequental without remap com pins.
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0x81, 0x7F, // Contrast (reset).
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0xDB, 0x20, // Vcomh (reset).
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0xD9, 0xF1, // Precharge period.
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0x8D, 0x14, // Charge pump.
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0xA6, // Positive display.
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0xA4, // Resume display.
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0xAF // Display on.
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};
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// [1] Do not set this to 0x00..0x07 on a 32 pixel high display, or vertical
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// addressing mode will mess up. 32 pixel high displays have only 4 pages
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// (0..3), still addressing logic accepts, but can't deal with the 0..7
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// meant for 64 pixel high displays.
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/**
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* Initializes the display's controller configuring the way of
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* displaying data.
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*/
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void display_init(void) {
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uint8_t i;
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displaybus_init(DISPLAY_I2C_ADDRESS);
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for (i = 0; i < sizeof(init_sequence); i++) {
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// Send last byte with 'last_byte' set.
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displaybus_write(init_sequence[i], (i == sizeof(init_sequence) - 1));
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}
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}
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/**
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Clear the screen. As this display supports many sophisticated commands,
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but not a simple 'clear', we have to overwrite the entire memory with
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zeros, byte by byte.
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*/
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void display_clear(void) {
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uint16_t i;
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// Set horizontal adressing mode.
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displaybus_write(0x00, 0);
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displaybus_write(0x20, 0);
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displaybus_write(0x00, 1);
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// Write 512 zeros.
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displaybus_write(0x40, 0);
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for (i = 0; i < 512; i++) {
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displaybus_write(0x00, (i == 511));
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}
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// Return to page adressing mode.
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displaybus_write(0x00, 0);
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displaybus_write(0x20, 0);
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displaybus_write(0x02, 1);
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}
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/**
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Prints the text at a given position.
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*/
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void display_text_P(uint8_t line, uint8_t column, PGM_P message) {
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uint8_t i;
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// Enter command mode.
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displaybus_write(0x00, 0);
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// Set line.
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displaybus_write(0xB0 | (line & 0x03), 0);
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// Set column.
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displaybus_write(0x00 | (column & 0x0F), 0);
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displaybus_write(0x10 | ((column >> 4) & 0x0F), 1);
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// Render text to bitmap to display.
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displaybus_write(0x40, 0);
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while (pgm_read_byte(message)) {
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uint8_t index = pgm_read_byte(message) - 0x20;
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// Send the character bitmap.
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for (i = 0; i < pgm_read_byte(&font[index].columns); i++) {
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displaybus_write(pgm_read_byte(&font[index].data[i]), 0);
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}
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// Send space between characters.
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for (i = 0; i < FONT_SYMBOL_SPACE; i++) {
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displaybus_write(0x00, 0);
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}
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message++;
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}
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// Send another space for transmission end.
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displaybus_write(0x00, 1);
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}
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#endif /* DISPLAY_TYPE_SSD1306 */
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