Electronics
DIT Software Library for the SSD1306 display controller IC - SSD1306.c
The source code can be found on GitHub.
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: . The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. . THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. \copyright DIT: 2017; Drechsler Information Technologies; www.drechsler-it.de \authors jrgdre: Joerg Drechsler; DIT \versions 1.0.0: 2017-06-21 jrgdre initial release */ #include <string.h> // we use memset() #include "SSD1306.h" #include "Framebuffer_SSD1306.h" /** * \brief Write a sequence of bytes to the SSD1306 * * \asserts (ssd1306 != NULL) * \asserts (sequence != NULL) */ static enum status_code ssd1306_sequence_write ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command sequence to , enum SSD1306_Datatype const datatype //< type of data to write , uint8_t *const sequence //< byte sequence to write , uint16_t const sequence_length //< length of sequence ) { enum status_code status; Assert( ssd1306 != NULL ); Assert( sequence != NULL ); if ( sequence_length < 1 ){ status = STATUS_OK; goto done; } struct Com_Driver com_driver = ssd1306->com_driver; void *com_module = com_driver.com_module; bool send_stop_org = com_driver.get_send_stop( com_module ); // save module's original setting com_driver.set_send_stop( com_module, false ); // do not release the i2c bus until finished sending the whole sequence uint8_t bytes[2]; bytes[0] = datatype; // send the command sequence byte by byte for( uint_fast32_t idx = 0; idx < sequence_length; idx++ ) { bytes[1] = sequence[idx]; status = com_driver.write_wait( com_module, ssd1306->address, bytes, 2 ); if( status != STATUS_OK ) { goto done; } } done: ssd1306->com_driver.set_send_stop( com_module, send_stop_org ); // restore driver's original setting ssd1306->com_driver.send_stop ( com_module ); // release the i2c bus return status; }; /** * \asserts (ssd1306 != NULL) * \asserts (sequence != NULL) */ enum status_code ssd1306_command_sequence_write ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command sequence to , uint8_t *const command_sequence //< command sequence to write , uint16_t const sequence_length //< length of command sequence ) { Assert( ssd1306 != NULL ); Assert( command_sequence != NULL ); return ssd1306_sequence_write( ssd1306, SSD1306_COMMAND, command_sequence, sequence_length ); }; /** * \asserts (ssd1306 != NULL) * \asserts (sequence != NULL) */ enum status_code ssd1306_data_sequence_write ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command sequence to , uint8_t *const data_sequence //< data sequence to write , uint16_t const sequence_length //< length of data sequence ) { Assert( ssd1306 != NULL ); Assert( data_sequence != NULL ); return ssd1306_sequence_write( ssd1306, SSD1306_DATA, data_sequence, sequence_length ); }; /** * \asserts (ssd1306 != NULL) */ enum status_code ssd1306_init ( struct SSD1306 *ssd1306 ){ Assert( ssd1306 != NULL ); enum status_code status = STATUS_OK ; uint8_t width = 128 ; uint8_t height = ssd1306->geometry ; // see declaration of geometry, why this works uint8_t pages = (ssd1306->geometry >> 3); uint8_t contrast ; uint8_t precharge; uint8_t hw_conf ; switch (ssd1306->geometry) { case SSD1306_GEOMETRY_128x32: hw_conf = SSD1306_COM_PIN_CONFIGURATION_SEQUENTIAL | SSD1306_COM_PIN_REMAP_DISABLE; break; case SSD1306_GEOMETRY_128x64: hw_conf = SSD1306_COM_PIN_CONFIGURATION_ALTERNATIVE; break; }; switch (ssd1306->charge_pump_source) { case SSD1306_CHARGE_PUMP_SOURCE_EXTERNAL_VCC: precharge = 0x22; contrast = 0x9F; break; case SSD1306_CHARGE_PUMP_SOURCE_INTERNAL_VCC: precharge = 0xF1; contrast = 0xCF; break; } #define SSD1306_INIT_SEQUENCE_LENGTH 25 uint8_t init_sequence[SSD1306_INIT_SEQUENCE_LENGTH] = { // display control SSD1306_DISPLAY_OFF , // turn display off for reconfiguration // hardware configuration SSD1306_SET_CHARGE_PUMP_SOURCE , ssd1306->charge_pump_source , // configure and enable charge pump SSD1306_SET_MULTIPLEX_RATIO , height - 1 , // value is based on display height SSD1306_SET_COM_PINS_HARDWARE_CONFIGURATION , hw_conf , // // timing and driving scheme configuration SSD1306_SET_DISPLAY_OSC_FREQ_AND_CLOCK_DIV , 0x80 , SSD1306_SET_PRECHARGE_PERIODE , precharge , SSD1306_SET_VCOMH_DESELECT_LEVEL , SSD1306_VCOMH_0p77 , // addressing mode configuration SSD1306_SET_MEMORY_ADRESSING_MODE , SSD1306_ADDR_MODE_HORIZONTAL, // page 0 from col 0 to col 127, than page 1 from col 0 to col127 ->->-> (auto increment col, page) SSD1306_SET_PAGE_ADRESSES , 0x00, pages - 1 , // initial page-range to send data to: start SSD1306_SET_COLUMN_ADRESSES , 0x00, width - 1 , // initial column to send data to // fundamentals SSD1306_SET_DISPLAY_RESUME_RAM , // show GDDRAM content on DISPLAY_ON SSD1306_SET_DISPLAY_NORMAL , // normal picture SSD1306_SET_CONTRAST , contrast , // set an initial contrast value }; status = ssd1306_command_sequence_write( ssd1306, init_sequence, SSD1306_INIT_SEQUENCE_LENGTH ); if( status != STATUS_OK ){ goto done; } if( ssd1306->flip_horizontal ){ #define SSD1306_HFLIP_SEQUENCE_LENGTH 1 uint8_t hflip_sequence[SSD1306_HFLIP_SEQUENCE_LENGTH] = { SSD1306_SET_COM_OUTPUT_DIRECTION_REMAP }; status = ssd1306_command_sequence_write( ssd1306, hflip_sequence, SSD1306_HFLIP_SEQUENCE_LENGTH ); if( status != STATUS_OK ){ goto done; } } if( ssd1306->flip_vertical ){ #define SSD1306_VFLIP_SEQUENCE_LENGTH 1 uint8_t vflip_sequence[SSD1306_VFLIP_SEQUENCE_LENGTH] = { SSD1306_SET_SEGMENT_REMAP }; status = ssd1306_command_sequence_write( ssd1306, vflip_sequence, SSD1306_VFLIP_SEQUENCE_LENGTH ); if( status != STATUS_OK ){ goto done; } } done: return status; }; /** * \asserts (ssd1306 != NULL) */ enum status_code ssd1306_display_on ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command to , bool const value //< display on state to set (true: ON; false: OFF) ){ Assert( ssd1306 != NULL ); #define SSD1306_DISPLAY_STATE_SEQUENCE_LENGTH 1 uint8_t sequence[SSD1306_DISPLAY_STATE_SEQUENCE_LENGTH] = { SSD1306_DISPLAY_ON }; if( !value ) { sequence[0] = SSD1306_DISPLAY_OFF; } return ssd1306_command_sequence_write( ssd1306, sequence, SSD1306_DISPLAY_STATE_SEQUENCE_LENGTH ); }; /** * \brief Send the page and column addresses of the next tile to write data to, to the FeatherWing * * \asserts (ssd1306 != NULL) */ static enum status_code set_tile_next ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command to , uint8_t const page_start //< first column to write next data byte to , uint8_t const column_start //< first column to write next data byte to ){ Assert( ssd1306 != NULL ); uint8_t page_end = (ssd1306->geometry >> 3) - 1; uint8_t column_end = 127; return ssd1306_set_page_range ( ssd1306, page_start , page_end ) || ssd1306_set_column_range( ssd1306, column_start, column_end ); }; /** * \brief Returns the tiles dirty threshold base on the display geometry */ inline static uint32_t get_tiles_dirty_threshold( enum SSD1306_Geometry geometry ){ uint32_t result; switch ( geometry ) { case SSD1306_GEOMETRY_128x32: result = 147; break; case SSD1306_GEOMETRY_128x64: result = 294; break; } return result; } /** * \asserts ssd1306 != NULL * \asserts ssd1306.com_driver != NULL * \asserts ssd1306.com_driver.com_module != NULL * * \asserts framebuffer != NULL * \asserts framebuffer->user_data != NULL * \asserts framebuffer->user_data->bytes > 0 * \asserts framebuffer->user_data->tiles != NULL * \asserts framebuffer->user_data->tiles _dirty != NULL */ enum status_code ssd1306_display_update_all ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the update to , struct Framebuffer *const framebuffer //< framebuffer holding the data to display on the OLED ){ Assert( ssd1306 != NULL ); Assert( ssd1306.com_driver != NULL ); Assert( ssd1306.com_driver.com_module != NULL ); struct Com_Driver com_driver = ssd1306->com_driver ; void *com_module = com_driver.com_module; Assert( framebuffer->user_data != NULL ); struct Framebuffer_SSD1306 *fb_ssd1306 = (struct Framebuffer_SSD1306 *)framebuffer->user_data; Assert( fb_ssd1306->bytes > 0 ); Assert( fb_ssd1306->tiles != NULL ); Assert( fb_ssd1306->tiles_dirty != NULL ); bool send_stop_org = com_driver.get_send_stop( com_module ); enum status_code status = STATUS_ERR_NOT_INITIALIZED; uint32_t tile_idx = 0; com_driver.set_send_stop( com_module, false ); // do not release the i2c bus until finished sending all the tiles // we use a while loop to break if there is an error and still be able to perform some cleanup while( status != STATUS_OK ) { // initialize the [page,column] start point for the update status = set_tile_next( ssd1306, 0x00, 0x00 ); if( status != STATUS_OK ){ goto done; } // send the fb_ssd1306 byte by byte for( uint_fast16_t page=0; page < fb_ssd1306->pages; page++ ) { for( uint_fast16_t column=0; column < fb_ssd1306->columns; column++ ) { tile_idx = (page*fb_ssd1306->columns) + column; status = ssd1306_data_sequence_write( ssd1306, &fb_ssd1306->tiles[tile_idx], 1); if( status != STATUS_OK ) { goto done; } } } memset( (void *)fb_ssd1306->tiles_dirty, 0x00, fb_ssd1306->bytes >> 3 ); // mark all tiles as clean fb_ssd1306->tiles_dirty_count = 0; } done: com_driver.send_stop ( com_module ); // release i2c bus com_driver.set_send_stop( com_module, send_stop_org ); // restore original setting return status; }; /** * \asserts ssd1306 != NULL * \asserts ssd1306.com_driver != NULL * \asserts ssd1306.com_driver.com_module != NULL * * \asserts framebuffer != NULL * \asserts framebuffer->user_data != NULL * \asserts framebuffer->user_data->bytes > 0 * \asserts framebuffer->user_data->tiles != NULL * \asserts framebuffer->user_data->tiles _dirty != NULL */ enum status_code ssd1306_display_update_differential ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the update to , struct Framebuffer *const framebuffer //< framebuffer holding the data to display on the OLED ){ Assert( ssd1306 != NULL ); Assert( ssd1306.com_driver != NULL ); Assert( ssd1306.com_driver.com_module != NULL ); struct Com_Driver com_driver = ssd1306->com_driver ; void *com_module = com_driver.com_module; Assert( framebuffer->user_data != NULL ); struct Framebuffer_SSD1306 *fb_ssd1306 = (struct Framebuffer_SSD1306 *)framebuffer->user_data; Assert( fb_ssd1306->bytes > 0 ); Assert( fb_ssd1306->tiles != NULL ); Assert( fb_ssd1306->tiles_dirty != NULL ); bool send_stop_org = com_driver.get_send_stop( com_module ); enum status_code status = STATUS_ERR_NOT_INITIALIZED; uint16_t tiles_dirty_byte_idx = 0; // 1 bit per tile in tiles_dirty uint8_t tiles_dirty_bit_idx = 0; // bit position of tile in tiles_dirty index byte uint32_t tile_idx = 0; // tile the pixel is in uint32_t tile_idx_prev = 0; // idx of the tile update last bool tile_is_dirty = false; // current value bool error = false; // true if an error occurred during processing com_driver.set_send_stop( com_module, false ); // do not release the i2c bus until finished sending all the tiles // we use a while loop to break if there is an error and still be able to perform some cleanup while( status != STATUS_OK ) { // send the dirty tiles byte by byte for( uint_fast16_t page=0; page < fb_ssd1306->pages; page++ ) { for( uint_fast16_t column=0; column < fb_ssd1306->columns; column++ ) { tile_idx = ( page * fb_ssd1306->columns ) + column; // tile the pixel is in tiles_dirty_byte_idx = tile_idx >> 3; // 1 bit per tile in tiles_dirty tiles_dirty_bit_idx = tile_idx % (tiles_dirty_byte_idx << 3); // bit position of tile in tiles_dirty_idx byte tile_is_dirty = \ ( fb_ssd1306->tiles_dirty[ tiles_dirty_byte_idx ] & ( 0x1 << tiles_dirty_bit_idx ) ) >> tiles_dirty_bit_idx; // current value if( tile_is_dirty ){ // tile marked as dirty if(( tile_idx == 0 ) // first tile || ( tile_idx_prev != tile_idx-1 ) // we skipped one or more tiles in the meantime ){ status = set_tile_next( ssd1306, page, column ); // tell the ssd1306 which tile comes next if( status != STATUS_OK ){ goto done; } } status = ssd1306_data_sequence_write( ssd1306, &fb_ssd1306->tiles[(page*fb_ssd1306->columns) + column], 1); if( status != STATUS_OK ) { goto done; } fb_ssd1306->tiles_dirty[ tiles_dirty_byte_idx ] &= ~( 0x1 << tiles_dirty_bit_idx ); // tile is clean now fb_ssd1306->tiles_dirty_count--; // decrease dirty tiles count if( fb_ssd1306->tiles_dirty_count < 1 ){ goto done; // nothing left to do } tile_idx_prev = tile_idx; } } if(( error ) || ( fb_ssd1306->tiles_dirty_count < 1 ) // nothing left to do ){ break; } } } done: com_driver.send_stop ( com_module ); // release i2c bus com_driver.set_send_stop( com_module , send_stop_org ); // restore original setting return status; }; /** * \asserts ssd1306 != NULL * * \asserts framebuffer != NULL * \asserts framebuffer->user_data != NULL * \asserts framebuffer->user_data->bytes > 0 * \asserts framebuffer->user_data->tiles != NULL * \asserts framebuffer->user_data->tiles _dirty != NULL */ enum status_code ssd1306_display_update ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the update to , struct Framebuffer *const framebuffer //< framebuffer holding the data to display on the OLED ){ Assert( ssd1306 != NULL ); Assert( framebuffer != NULL ); Assert( framebuffer->user_data != NULL ); struct Framebuffer_SSD1306 *fb_ssd1306 = (struct Framebuffer_SSD1306 *)framebuffer->user_data; // in user_data we should find the pointer to the SSD1306 framebuffer Assert( fb_ssd1306->bytes > 0 ); Assert( fb_ssd1306->tiles != NULL ); Assert( fb_ssd1306->tiles_dirty != NULL ); enum status_code status; if ( fb_ssd1306->tiles_dirty_count < 1 ){ // nothing to do status = STATUS_OK; goto done; } uint32_t tiles_dirty_threshold = get_tiles_dirty_threshold( ssd1306->geometry ); if( fb_ssd1306->tiles_dirty_count > tiles_dirty_threshold ) { status = ssd1306_display_update_all ( ssd1306, framebuffer ); } else { // if the number of tiles dirty is greater than the threshold status = ssd1306_display_update_differential( ssd1306, framebuffer ); // it is faster to send the whole buffer } done: return status; }; /** * \asserts (ssd1306 != NULL) */ enum status_code ssd1306_set_column_range ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command to , uint8_t const column_start //< first column to write next data byte to , uint8_t const column_end //< last column to write a data byte to ){ Assert( ssd1306 != NULL ); #define SSD1306_SET_COLUMN_RANGE_SEQUENCE_LENGTH 3 uint8_t sequence[SSD1306_SET_COLUMN_RANGE_SEQUENCE_LENGTH] = { SSD1306_SET_COLUMN_ADRESSES, column_start, column_end }; return ssd1306_command_sequence_write( ssd1306, sequence, SSD1306_SET_COLUMN_RANGE_SEQUENCE_LENGTH ); } /** * \asserts (ssd1306 != NULL) */ enum status_code ssd1306_set_page_range ( struct SSD1306 *const ssd1306 //< data structure of the SSD1306 controller to write the command to , uint8_t const page_start //< first column to write next data byte to , uint8_t const page_end //< last column to write a data byte to ){ Assert( ssd1306 != NULL ); #define SSD1306_SET_PAGE_ADDRESS_SEQUENCE_LENGTH 3 uint8_t sequence[SSD1306_SET_PAGE_ADDRESS_SEQUENCE_LENGTH] = { SSD1306_SET_PAGE_ADRESSES, page_start, page_end }; return ssd1306_command_sequence_write( ssd1306, sequence, SSD1306_SET_PAGE_ADDRESS_SEQUENCE_LENGTH ); } |