summaryrefslogtreecommitdiffstats
path: root/drivers/oled/oled_driver.c
blob: bbf010a09086b6e30910ee8570c7999d3512c839 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
/*
Copyright 2019 Ryan Caltabiano <https://github.com/XScorpion2>

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 "i2c_master.h"
#include "oled_driver.h"
#include OLED_FONT_H
#include "timer.h"
#include "print.h"

#include <string.h>

#include "progmem.h"

// Used commands from spec sheet: https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
// for SH1106: https://www.velleman.eu/downloads/29/infosheets/sh1106_datasheet.pdf

// Fundamental Commands
#define CONTRAST 0x81
#define DISPLAY_ALL_ON 0xA5
#define DISPLAY_ALL_ON_RESUME 0xA4
#define NORMAL_DISPLAY 0xA6
#define DISPLAY_ON 0xAF
#define DISPLAY_OFF 0xAE
#define NOP 0xE3

// Scrolling Commands
#define ACTIVATE_SCROLL 0x2F
#define DEACTIVATE_SCROLL 0x2E
#define SCROLL_RIGHT 0x26
#define SCROLL_LEFT 0x27
#define SCROLL_RIGHT_UP 0x29
#define SCROLL_LEFT_UP 0x2A

// Addressing Setting Commands
#define MEMORY_MODE 0x20
#define COLUMN_ADDR 0x21
#define PAGE_ADDR 0x22
#define PAM_SETCOLUMN_LSB 0x00
#define PAM_SETCOLUMN_MSB 0x10
#define PAM_PAGE_ADDR 0xB0  // 0xb0 -- 0xb7

// Hardware Configuration Commands
#define DISPLAY_START_LINE 0x40
#define SEGMENT_REMAP 0xA0
#define SEGMENT_REMAP_INV 0xA1
#define MULTIPLEX_RATIO 0xA8
#define COM_SCAN_INC 0xC0
#define COM_SCAN_DEC 0xC8
#define DISPLAY_OFFSET 0xD3
#define COM_PINS 0xDA
#define COM_PINS_SEQ 0x02
#define COM_PINS_ALT 0x12
#define COM_PINS_SEQ_LR 0x22
#define COM_PINS_ALT_LR 0x32

// Timing & Driving Commands
#define DISPLAY_CLOCK 0xD5
#define PRE_CHARGE_PERIOD 0xD9
#define VCOM_DETECT 0xDB

// Charge Pump Commands
#define CHARGE_PUMP 0x8D

// Misc defines
#define OLED_BLOCK_COUNT (sizeof(OLED_BLOCK_TYPE) * 8)
#define OLED_BLOCK_SIZE (OLED_MATRIX_SIZE / OLED_BLOCK_COUNT)

// i2c defines
#define I2C_CMD 0x00
#define I2C_DATA 0x40
#if defined(__AVR__)
#    define I2C_TRANSMIT_P(data) i2c_transmit_P((OLED_DISPLAY_ADDRESS << 1), &data[0], sizeof(data), OLED_I2C_TIMEOUT)
#else  // defined(__AVR__)
#    define I2C_TRANSMIT_P(data) i2c_transmit((OLED_DISPLAY_ADDRESS << 1), &data[0], sizeof(data), OLED_I2C_TIMEOUT)
#endif  // defined(__AVR__)
#define I2C_TRANSMIT(data) i2c_transmit((OLED_DISPLAY_ADDRESS << 1), &data[0], sizeof(data), OLED_I2C_TIMEOUT)
#define I2C_WRITE_REG(mode, data, size) i2c_writeReg((OLED_DISPLAY_ADDRESS << 1), mode, data, size, OLED_I2C_TIMEOUT)

#define HAS_FLAGS(bits, flags) ((bits & flags) == flags)

// Display buffer's is the same as the OLED memory layout
// this is so we don't end up with rounding errors with
// parts of the display unusable or don't get cleared correctly
// and also allows for drawing & inverting
uint8_t         oled_buffer[OLED_MATRIX_SIZE];
uint8_t *       oled_cursor;
OLED_BLOCK_TYPE oled_dirty          = 0;
bool            oled_initialized    = false;
bool            oled_active         = false;
bool            oled_scrolling      = false;
uint8_t         oled_rotation       = 0;
uint8_t         oled_rotation_width = 0;
uint8_t         oled_scroll_speed   = 0;  // this holds the speed after being remapped to ssd1306 internal values
uint8_t         oled_scroll_start   = 0;
uint8_t         oled_scroll_end     = 7;
#if OLED_TIMEOUT > 0
uint32_t oled_timeout;
#endif
#if OLED_SCROLL_TIMEOUT > 0
uint32_t oled_scroll_timeout;
#endif

// Internal variables to reduce math instructions

#if defined(__AVR__)
// identical to i2c_transmit, but for PROGMEM since all initialization is in PROGMEM arrays currently
// probably should move this into i2c_master...
static i2c_status_t i2c_transmit_P(uint8_t address, const uint8_t *data, uint16_t length, uint16_t timeout) {
    i2c_status_t status = i2c_start(address | I2C_WRITE, timeout);

    for (uint16_t i = 0; i < length && status >= 0; i++) {
        status = i2c_write(pgm_read_byte((const char *)data++), timeout);
        if (status) break;
    }

    i2c_stop();

    return status;
}
#endif

// Flips the rendering bits for a character at the current cursor position
static void InvertCharacter(uint8_t *cursor) {
    const uint8_t *end = cursor + OLED_FONT_WIDTH;
    while (cursor < end) {
        *cursor = ~(*cursor);
        cursor++;
    }
}

bool oled_init(uint8_t rotation) {
    oled_rotation = oled_init_user(rotation);
    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
        oled_rotation_width = OLED_DISPLAY_WIDTH;
    } else {
        oled_rotation_width = OLED_DISPLAY_HEIGHT;
    }
    i2c_init();

    static const uint8_t PROGMEM display_setup1[] = {
        I2C_CMD,
        DISPLAY_OFF,
        DISPLAY_CLOCK,
        0x80,
        MULTIPLEX_RATIO,
        OLED_DISPLAY_HEIGHT - 1,
        DISPLAY_OFFSET,
        0x00,
        DISPLAY_START_LINE | 0x00,
        CHARGE_PUMP,
        0x14,
#if (OLED_IC != OLED_IC_SH1106)
        // MEMORY_MODE is unsupported on SH1106 (Page Addressing only)
        MEMORY_MODE,
        0x00,  // Horizontal addressing mode
#endif
    };
    if (I2C_TRANSMIT_P(display_setup1) != I2C_STATUS_SUCCESS) {
        print("oled_init cmd set 1 failed\n");
        return false;
    }

    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_180)) {
        static const uint8_t PROGMEM display_normal[] = {I2C_CMD, SEGMENT_REMAP_INV, COM_SCAN_DEC};
        if (I2C_TRANSMIT_P(display_normal) != I2C_STATUS_SUCCESS) {
            print("oled_init cmd normal rotation failed\n");
            return false;
        }
    } else {
        static const uint8_t PROGMEM display_flipped[] = {I2C_CMD, SEGMENT_REMAP, COM_SCAN_INC};
        if (I2C_TRANSMIT_P(display_flipped) != I2C_STATUS_SUCCESS) {
            print("display_flipped failed\n");
            return false;
        }
    }

    static const uint8_t PROGMEM display_setup2[] = {I2C_CMD, COM_PINS, OLED_COM_PINS, CONTRAST, 0x8F, PRE_CHARGE_PERIOD, 0xF1, VCOM_DETECT, 0x40, DISPLAY_ALL_ON_RESUME, NORMAL_DISPLAY, DEACTIVATE_SCROLL, DISPLAY_ON};
    if (I2C_TRANSMIT_P(display_setup2) != I2C_STATUS_SUCCESS) {
        print("display_setup2 failed\n");
        return false;
    }

#if OLED_TIMEOUT > 0
    oled_timeout = timer_read32() + OLED_TIMEOUT;
#endif
#if OLED_SCROLL_TIMEOUT > 0
    oled_scroll_timeout = timer_read32() + OLED_SCROLL_TIMEOUT;
#endif

    oled_clear();
    oled_initialized = true;
    oled_active      = true;
    oled_scrolling   = false;
    return true;
}

__attribute__((weak)) oled_rotation_t oled_init_user(oled_rotation_t rotation) { return rotation; }

void oled_clear(void) {
    memset(oled_buffer, 0, sizeof(oled_buffer));
    oled_cursor = &oled_buffer[0];
    oled_dirty  = -1;  // -1 will be max value as long as display_dirty is unsigned type
}

static void calc_bounds(uint8_t update_start, uint8_t *cmd_array) {
    // Calculate commands to set memory addressing bounds.
    uint8_t start_page   = OLED_BLOCK_SIZE * update_start / OLED_DISPLAY_WIDTH;
    uint8_t start_column = OLED_BLOCK_SIZE * update_start % OLED_DISPLAY_WIDTH;
#if (OLED_IC == OLED_IC_SH1106)
    // Commands for Page Addressing Mode. Sets starting page and column; has no end bound.
    // Column value must be split into high and low nybble and sent as two commands.
    cmd_array[0] = PAM_PAGE_ADDR | start_page;
    cmd_array[1] = PAM_SETCOLUMN_LSB | ((OLED_COLUMN_OFFSET + start_column) & 0x0f);
    cmd_array[2] = PAM_SETCOLUMN_MSB | ((OLED_COLUMN_OFFSET + start_column) >> 4 & 0x0f);
    cmd_array[3] = NOP;
    cmd_array[4] = NOP;
    cmd_array[5] = NOP;
#else
    // Commands for use in Horizontal Addressing mode.
    cmd_array[1] = start_column;
    cmd_array[4] = start_page;
    cmd_array[2] = (OLED_BLOCK_SIZE + OLED_DISPLAY_WIDTH - 1) % OLED_DISPLAY_WIDTH + cmd_array[1];
    cmd_array[5] = (OLED_BLOCK_SIZE + OLED_DISPLAY_WIDTH - 1) / OLED_DISPLAY_WIDTH - 1;
#endif
}

static void calc_bounds_90(uint8_t update_start, uint8_t *cmd_array) {
    cmd_array[1] = OLED_BLOCK_SIZE * update_start / OLED_DISPLAY_HEIGHT * 8;
    cmd_array[4] = OLED_BLOCK_SIZE * update_start % OLED_DISPLAY_HEIGHT;
    cmd_array[2] = (OLED_BLOCK_SIZE + OLED_DISPLAY_HEIGHT - 1) / OLED_DISPLAY_HEIGHT * 8 - 1 + cmd_array[1];
    ;
    cmd_array[5] = (OLED_BLOCK_SIZE + OLED_DISPLAY_HEIGHT - 1) % OLED_DISPLAY_HEIGHT / 8;
}

uint8_t crot(uint8_t a, int8_t n) {
    const uint8_t mask = 0x7;
    n &= mask;
    return a << n | a >> (-n & mask);
}

static void rotate_90(const uint8_t *src, uint8_t *dest) {
    for (uint8_t i = 0, shift = 7; i < 8; ++i, --shift) {
        uint8_t selector = (1 << i);
        for (uint8_t j = 0; j < 8; ++j) {
            dest[i] |= crot(src[j] & selector, shift - (int8_t)j);
        }
    }
}

void oled_render(void) {
    // Do we have work to do?
    if (!oled_dirty || oled_scrolling) {
        return;
    }

    // Find first dirty block
    uint8_t update_start = 0;
    while (!(oled_dirty & (1 << update_start))) {
        ++update_start;
    }

    // Set column & page position
    static uint8_t display_start[] = {I2C_CMD, COLUMN_ADDR, 0, OLED_DISPLAY_WIDTH - 1, PAGE_ADDR, 0, OLED_DISPLAY_HEIGHT / 8 - 1};
    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
        calc_bounds(update_start, &display_start[1]);  // Offset from I2C_CMD byte at the start
    } else {
        calc_bounds_90(update_start, &display_start[1]);  // Offset from I2C_CMD byte at the start
    }

    // Send column & page position
    if (I2C_TRANSMIT(display_start) != I2C_STATUS_SUCCESS) {
        print("oled_render offset command failed\n");
        return;
    }

    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
        // Send render data chunk as is
        if (I2C_WRITE_REG(I2C_DATA, &oled_buffer[OLED_BLOCK_SIZE * update_start], OLED_BLOCK_SIZE) != I2C_STATUS_SUCCESS) {
            print("oled_render data failed\n");
            return;
        }
    } else {
        // Rotate the render chunks
        const static uint8_t source_map[] = OLED_SOURCE_MAP;
        const static uint8_t target_map[] = OLED_TARGET_MAP;

        static uint8_t temp_buffer[OLED_BLOCK_SIZE];
        memset(temp_buffer, 0, sizeof(temp_buffer));
        for (uint8_t i = 0; i < sizeof(source_map); ++i) {
            rotate_90(&oled_buffer[OLED_BLOCK_SIZE * update_start + source_map[i]], &temp_buffer[target_map[i]]);
        }

        // Send render data chunk after rotating
        if (I2C_WRITE_REG(I2C_DATA, &temp_buffer[0], OLED_BLOCK_SIZE) != I2C_STATUS_SUCCESS) {
            print("oled_render90 data failed\n");
            return;
        }
    }

    // Turn on display if it is off
    oled_on();

    // Clear dirty flag
    oled_dirty &= ~(1 << update_start);
}

void oled_set_cursor(uint8_t col, uint8_t line) {
    uint16_t index = line * oled_rotation_width + col * OLED_FONT_WIDTH;

    // Out of bounds?
    if (index >= OLED_MATRIX_SIZE) {
        index = 0;
    }

    oled_cursor = &oled_buffer[index];
}

void oled_advance_page(bool clearPageRemainder) {
    uint16_t index     = oled_cursor - &oled_buffer[0];
    uint8_t  remaining = oled_rotation_width - (index % oled_rotation_width);

    if (clearPageRemainder) {
        // Remaining Char count
        remaining = remaining / OLED_FONT_WIDTH;

        // Write empty character until next line
        while (remaining--) oled_write_char(' ', false);
    } else {
        // Next page index out of bounds?
        if (index + remaining >= OLED_MATRIX_SIZE) {
            index     = 0;
            remaining = 0;
        }

        oled_cursor = &oled_buffer[index + remaining];
    }
}

void oled_advance_char(void) {
    uint16_t nextIndex      = oled_cursor - &oled_buffer[0] + OLED_FONT_WIDTH;
    uint8_t  remainingSpace = oled_rotation_width - (nextIndex % oled_rotation_width);

    // Do we have enough space on the current line for the next character
    if (remainingSpace < OLED_FONT_WIDTH) {
        nextIndex += remainingSpace;
    }

    // Did we go out of bounds
    if (nextIndex >= OLED_MATRIX_SIZE) {
        nextIndex = 0;
    }

    // Update cursor position
    oled_cursor = &oled_buffer[nextIndex];
}

// Main handler that writes character data to the display buffer
void oled_write_char(const char data, bool invert) {
    // Advance to the next line if newline
    if (data == '\n') {
        // Old source wrote ' ' until end of line...
        oled_advance_page(true);
        return;
    }

    if (data == '\r') {
        oled_advance_page(false);
        return;
    }

    // copy the current render buffer to check for dirty after
    static uint8_t oled_temp_buffer[OLED_FONT_WIDTH];
    memcpy(&oled_temp_buffer, oled_cursor, OLED_FONT_WIDTH);

    _Static_assert(sizeof(font) >= ((OLED_FONT_END + 1 - OLED_FONT_START) * OLED_FONT_WIDTH), "OLED_FONT_END references outside array");

    // set the reder buffer data
    uint8_t cast_data = (uint8_t)data;  // font based on unsigned type for index
    if (cast_data < OLED_FONT_START || cast_data > OLED_FONT_END) {
        memset(oled_cursor, 0x00, OLED_FONT_WIDTH);
    } else {
        const uint8_t *glyph = &font[(cast_data - OLED_FONT_START) * OLED_FONT_WIDTH];
        memcpy_P(oled_cursor, glyph, OLED_FONT_WIDTH);
    }

    // Invert if needed
    if (invert) {
        InvertCharacter(oled_cursor);
    }

    // Dirty check
    if (memcmp(&oled_temp_buffer, oled_cursor, OLED_FONT_WIDTH)) {
        uint16_t index = oled_cursor - &oled_buffer[0];
        oled_dirty |= (1 << (index / OLED_BLOCK_SIZE));
        // Edgecase check if the written data spans the 2 chunks
        oled_dirty |= (1 << ((index + OLED_FONT_WIDTH) / OLED_BLOCK_SIZE));
    }

    // Finally move to the next char
    oled_advance_char();
}

void oled_write(const char *data, bool invert) {
    const char *end = data + strlen(data);
    while (data < end) {
        oled_write_char(*data, invert);
        data++;
    }
}

void oled_write_ln(const char *data, bool invert) {
    oled_write(data, invert);
    oled_advance_page(true);
}

void oled_pan(bool left) {
    uint16_t i = 0;
    for (uint16_t y = 0; y < OLED_DISPLAY_HEIGHT / 8; y++) {
        if (left) {
            for (uint16_t x = 0; x < OLED_DISPLAY_WIDTH - 1; x++) {
                i              = y * OLED_DISPLAY_WIDTH + x;
                oled_buffer[i] = oled_buffer[i + 1];
            }
        } else {
            for (uint16_t x = OLED_DISPLAY_WIDTH - 1; x > 0; x--) {
                i              = y * OLED_DISPLAY_WIDTH + x;
                oled_buffer[i] = oled_buffer[i - 1];
            }
        }
    }
    oled_dirty = ~((OLED_BLOCK_TYPE)0);
}

oled_buffer_reader_t oled_read_raw(uint16_t start_index) {
    if (start_index > OLED_MATRIX_SIZE) start_index = OLED_MATRIX_SIZE;
    oled_buffer_reader_t ret_reader;
    ret_reader.current_element = &oled_buffer[start_index];
    ret_reader.remaining_element_count = OLED_MATRIX_SIZE - start_index;
    return ret_reader;
}

void oled_write_raw_byte(const char data, uint16_t index) {
    if (index > OLED_MATRIX_SIZE) index = OLED_MATRIX_SIZE;
    if (oled_buffer[index] == data) return;
    oled_buffer[index] = data;
    oled_dirty |= (1 << (index / OLED_BLOCK_SIZE));
}

void oled_write_raw(const char *data, uint16_t size) {
    if (size > OLED_MATRIX_SIZE) size = OLED_MATRIX_SIZE;
    for (uint16_t i = 0; i < size; i++) {
        if (oled_buffer[i] == data[i]) continue;
        oled_buffer[i] = data[i];
        oled_dirty |= (1 << (i / OLED_BLOCK_SIZE));
    }
}

void oled_write_pixel(uint8_t x, uint8_t y, bool on) {
    if (x >= OLED_DISPLAY_WIDTH || y >= OLED_DISPLAY_HEIGHT) {
        return;
    }
    uint16_t index = x + (y / 8) * OLED_DISPLAY_WIDTH;
    if (on) {
        oled_buffer[index] |= (1 << (y % 8));
    } else {
        oled_buffer[index] &= ~(1 << (y % 8));
    }
    oled_dirty |= (1 << (index / OLED_BLOCK_SIZE));
}

#if defined(__AVR__)
void oled_write_P(const char *data, bool invert) {
    uint8_t c = pgm_read_byte(data);
    while (c != 0) {
        oled_write_char(c, invert);
        c = pgm_read_byte(++data);
    }
}

void oled_write_ln_P(const char *data, bool invert) {
    oled_write_P(data, invert);
    oled_advance_page(true);
}

void oled_write_raw_P(const char *data, uint16_t size) {
    if (size > OLED_MATRIX_SIZE) size = OLED_MATRIX_SIZE;
    for (uint16_t i = 0; i < size; i++) {
        uint8_t c = pgm_read_byte(data++);
        if (oled_buffer[i] == c) continue;
        oled_buffer[i] = c;
        oled_dirty |= (1 << (i / OLED_BLOCK_SIZE));
    }
}
#endif  // defined(__AVR__)

bool oled_on(void) {
#if OLED_TIMEOUT > 0
    oled_timeout = timer_read32() + OLED_TIMEOUT;
#endif

    static const uint8_t PROGMEM display_on[] = {I2C_CMD, DISPLAY_ON};
    if (!oled_active) {
        if (I2C_TRANSMIT_P(display_on) != I2C_STATUS_SUCCESS) {
            print("oled_on cmd failed\n");
            return oled_active;
        }
        oled_active = true;
    }
    return oled_active;
}

bool oled_off(void) {
    static const uint8_t PROGMEM display_off[] = {I2C_CMD, DISPLAY_OFF};
    if (oled_active) {
        if (I2C_TRANSMIT_P(display_off) != I2C_STATUS_SUCCESS) {
            print("oled_off cmd failed\n");
            return oled_active;
        }
        oled_active = false;
    }
    return !oled_active;
}

// Set the specific 8 lines rows of the screen to scroll.
// 0 is the default for start, and 7 for end, which is the entire
// height of the screen.  For 128x32 screens, rows 4-7 are not used.
void oled_scroll_set_area(uint8_t start_line, uint8_t end_line) {
    oled_scroll_start = start_line;
    oled_scroll_end   = end_line;
}

void oled_scroll_set_speed(uint8_t speed) {
    // Sets the speed for scrolling... does not take effect
    // until scrolling is either started or restarted
    // the ssd1306 supports 8 speeds
    // FrameRate2   speed = 7
    // FrameRate3   speed = 4
    // FrameRate4   speed = 5
    // FrameRate5   speed = 0
    // FrameRate25  speed = 6
    // FrameRate64  speed = 1
    // FrameRate128 speed = 2
    // FrameRate256 speed = 3
    // for ease of use these are remaped here to be in order
    static const uint8_t scroll_remap[8] = {7, 4, 5, 0, 6, 1, 2, 3};
    oled_scroll_speed                    = scroll_remap[speed];
}

bool oled_scroll_right(void) {
    // Dont enable scrolling if we need to update the display
    // This prevents scrolling of bad data from starting the scroll too early after init
    if (!oled_dirty && !oled_scrolling) {
        uint8_t display_scroll_right[] = {I2C_CMD, SCROLL_RIGHT, 0x00, oled_scroll_start, oled_scroll_speed, oled_scroll_end, 0x00, 0xFF, ACTIVATE_SCROLL};
        if (I2C_TRANSMIT(display_scroll_right) != I2C_STATUS_SUCCESS) {
            print("oled_scroll_right cmd failed\n");
            return oled_scrolling;
        }
        oled_scrolling = true;
    }
    return oled_scrolling;
}

bool oled_scroll_left(void) {
    // Dont enable scrolling if we need to update the display
    // This prevents scrolling of bad data from starting the scroll too early after init
    if (!oled_dirty && !oled_scrolling) {
        uint8_t display_scroll_left[] = {I2C_CMD, SCROLL_LEFT, 0x00, oled_scroll_start, oled_scroll_speed, oled_scroll_end, 0x00, 0xFF, ACTIVATE_SCROLL};
        if (I2C_TRANSMIT(display_scroll_left) != I2C_STATUS_SUCCESS) {
            print("oled_scroll_left cmd failed\n");
            return oled_scrolling;
        }
        oled_scrolling = true;
    }
    return oled_scrolling;
}

bool oled_scroll_off(void) {
    if (oled_scrolling) {
        static const uint8_t PROGMEM display_scroll_off[] = {I2C_CMD, DEACTIVATE_SCROLL};
        if (I2C_TRANSMIT_P(display_scroll_off) != I2C_STATUS_SUCCESS) {
            print("oled_scroll_off cmd failed\n");
            return oled_scrolling;
        }
        oled_scrolling = false;
        oled_dirty     = -1;
    }
    return !oled_scrolling;
}

uint8_t oled_max_chars(void) {
    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
        return OLED_DISPLAY_WIDTH / OLED_FONT_WIDTH;
    }
    return OLED_DISPLAY_HEIGHT / OLED_FONT_WIDTH;
}

uint8_t oled_max_lines(void) {
    if (!HAS_FLAGS(oled_rotation, OLED_ROTATION_90)) {
        return OLED_DISPLAY_HEIGHT / OLED_FONT_HEIGHT;
    }
    return OLED_DISPLAY_WIDTH / OLED_FONT_HEIGHT;
}

void oled_task(void) {
    if (!oled_initialized) {
        return;
    }

    oled_set_cursor(0, 0);

    oled_task_user();

#if OLED_SCROLL_TIMEOUT > 0
    if (oled_dirty && oled_scrolling) {
        oled_scroll_timeout = timer_read32() + OLED_SCROLL_TIMEOUT;
        oled_scroll_off();
    }
#endif

    // Smart render system, no need to check for dirty
    oled_render();

    // Display timeout check
#if OLED_TIMEOUT > 0
    if (oled_active && timer_expired32(timer_read32(), oled_timeout)) {
        oled_off();
    }
#endif

#if OLED_SCROLL_TIMEOUT > 0
    if (!oled_scrolling && timer_expired32(timer_read32(), oled_scroll_timeout)) {
#    ifdef OLED_SCROLL_TIMEOUT_RIGHT
        oled_scroll_right();
#    else
        oled_scroll_left();
#    endif
    }
#endif
}

__attribute__((weak)) void oled_task_user(void) {}