ssd1309.c File Reference

SSD1309 display driver implementation file. More...

#include <stdbool.h>
#include "ssd1309.h"
#include "common.h"
#include "err.h"
#include "modules.h"
#include "stm32f401re.h"
#include "stm32f401re_gpio.h"
#include "stm32f401re_i2c.h"
#include "log.h"
#include "cmd.h"
#include "init.h"

Include dependency graph for ssd1309.c:

Go to the source code of this file.

Classes
struct	ssd1309_handle_s
	Internal structure representing the SSD1309 hardware instance. More...
struct	internal_state_s
	Internal state of the SysTick driver. More...

Macros
#define	SSD1309_ADDR_W   0x3C
	I2C write address for the SSD1309 (7-bit address 0x3C, write mode).
#define	SSD1309_ADDR_R   0x3D
	I2C read address for the SSD1309 (7-bit address 0x3D, read mode).
#define	SSD1309_PAGE_NUM   8
	Number of pages in the SSD1309 display (8 pages × 8 rows = 64 rows).
#define	SSD1309_BITS_IN_PAGE   8
	Number of pixel rows per page.
#define	SSD1309_COL_NUM   128
	Number of columns in the display.
#define	SSD1309_MAX_LINES   8
	Maximum number of text lines on the display (one per page).

Functions
static ERR_te	ssd1309_cmd_start_handler (uint32_t argc, char **argv)
	CLI handler for the "start" command. Starts the SSD1309 subsystem at runtime.
static ERR_te	ssd1309_cmd_stop_handler (uint32_t argc, char **argv)
	CLI handler for the "stop" command. Stops the SSD1309 subsystem at runtime.
static ERR_te	ssd1309_cmd_fillrect_handler (uint32_t argc, char **argv)
	CLI handler for the "fillrect" command. Fills a rectangle and updates the display.
static ERR_te	ssd1309_cmd_clearrect_handler (uint32_t argc, char **argv)
	CLI handler for the "clearrect" command. Clears a rectangle and updates the display.
static ERR_te	ssd1309_cmd_invertrect_handler (uint32_t argc, char **argv)
	CLI handler for the "invertrect" command. Inverts a rectangle and updates the display.
static ERR_te	ssd1309_cmd_drawtext_handler (uint32_t argc, char **argv)
	CLI handler for the "drawtext" command. Draws text on a line and updates the display.
static ERR_te	ssd1309_cmd_clearline_handler (uint32_t argc, char **argv)
	CLI handler for the "clearline" command. Clears a line and updates the display.
static ERR_te	ssd1309_cmd_invertline_handler (uint32_t argc, char **argv)
	CLI handler for the "invertline" command. Inverts a line and updates the display.
ERR_te	ssd1309_init_subsys (void)
	Initializes the SSD1309 subsystem.
ERR_te	ssd1309_deinit_subsys (void)
	Deinitializes the SSD1309 subsystem.
ERR_te	ssd1309_start_subsys (void)
	Starts the SSD1309 subsystem.
ERR_te	ssd1309_stop_subsys (void)
	Stops the SSD1309 subsystem.
ERR_te	ssd1309_get_def_cfg (SSD1309_CFG_ts *ssd1309_cfg_o)
	Populates a configuration structure with sensible default values.
ERR_te	ssd1309_init_handle (SSD1309_CFG_ts *ssd1309_cfg, SSD1309_HANDLE_ts **ssd1309_handle_o)
	Initializes the SSD1309 display handle and sends the configuration sequence.
ERR_te	ssd1309_draw_text (char const *text, uint8_t text_len, uint8_t line, bool force)
	Draws a text string into the framebuffer at the specified line.
ERR_te	ssd1309_draw_rect (uint8_t x_src, uint8_t y_src, uint8_t x_dest, uint8_t y_dest, bool force)
	Draws a filled rectangle into the framebuffer.
ERR_te	ssd1309_clear_line (uint8_t line, bool force)
	Clears a single display line in the framebuffer.
ERR_te	ssd1309_invert_line (uint8_t line, bool force)
	Inverts all pixels in a single display line in the framebuffer.
ERR_te	ssd1309_clear_rect (uint8_t x_src, uint8_t y_src, uint8_t x_dest, uint8_t y_dest, bool force)
	Clears a rectangular region in the framebuffer.
ERR_te	ssd1309_invert_rect (uint8_t x_src, uint8_t y_src, uint8_t x_dest, uint8_t y_dest, bool force)
	Inverts all pixels in a rectangular region of the framebuffer.
ERR_te	ssd1309_update (bool force)
	Flushes the internal framebuffer to the display over I2C.

Variables
const uint8_t	fonts8x8 [95][8]
	8×8 pixel font table for printable ASCII characters (0x20–0x7E).
static struct internal_state_s	internal_state
	Singleton instance of the SSD1309 subsystem internal state.
static CMD_INFO_ts	ssd1309_cmds []
	Table of CLI commands registered by the SSD1309 subsystem.
static CMD_CLIENT_INFO_ts	ssd1309_cmd_client_info
	Registration descriptor passed to the command subsystem.

Detailed Description

SSD1309 display driver implementation file.

Author

github.com/Baksi675

Version

0.1

Date

2025-11-28

Copyright

Copyright (c) 2025

Definition in file ssd1309.c.

Macro Definition Documentation

SSD1309_ADDR_W

#define SSD1309_ADDR_W   0x3C

I2C write address for the SSD1309 (7-bit address 0x3C, write mode).

Definition at line 26 of file ssd1309.c.

SSD1309_ADDR_R

#define SSD1309_ADDR_R   0x3D

I2C read address for the SSD1309 (7-bit address 0x3D, read mode).

Definition at line 28 of file ssd1309.c.

SSD1309_PAGE_NUM

#define SSD1309_PAGE_NUM   8

Number of pages in the SSD1309 display (8 pages × 8 rows = 64 rows).

Definition at line 30 of file ssd1309.c.

SSD1309_BITS_IN_PAGE

#define SSD1309_BITS_IN_PAGE   8

Number of pixel rows per page.

Definition at line 32 of file ssd1309.c.

SSD1309_COL_NUM

#define SSD1309_COL_NUM   128

Number of columns in the display.

Definition at line 34 of file ssd1309.c.

SSD1309_MAX_LINES

#define SSD1309_MAX_LINES   8

Maximum number of text lines on the display (one per page).

Definition at line 36 of file ssd1309.c.

Variable Documentation

fonts8x8

const uint8_t fonts8x8[95][8]

8×8 pixel font table for printable ASCII characters (0x20–0x7E).

Each entry contains 8 bytes representing one character glyph, where each byte is a column of 8 pixels (bit 0 = top row, bit 7 = bottom row). Index into the table as fonts8x8[char - 32]. Covers 95 characters: space (0x20) through tilde (0x7E).

Definition at line 48 of file ssd1309.c.

                                {
 
/* 0x20 ' ' */
{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
 
/* 0x21 '!' */
{0x00,0x00,0x00,0x5F,0x00,0x00,0x00,0x00},
 
/* 0x22 '"' */
{0x00,0x07,0x00,0x07,0x00,0x00,0x00,0x00},
 
/* 0x23 '#' */
{0x14,0x7F,0x14,0x7F,0x14,0x00,0x00,0x00},
 
/* 0x24 '$' */
{0x24,0x2A,0x7F,0x2A,0x12,0x00,0x00,0x00},
 
/* 0x25 '%' */
{0x23,0x13,0x08,0x64,0x62,0x00,0x00,0x00},
 
/* 0x26 '&' */
{0x36,0x49,0x55,0x22,0x50,0x00,0x00,0x00},
 
/* 0x27 ''' */
{0x00,0x05,0x03,0x00,0x00,0x00,0x00,0x00},
 
/* 0x28 '(' */
{0x00,0x1C,0x22,0x41,0x00,0x00,0x00,0x00},
 
/* 0x29 ')' */
{0x00,0x41,0x22,0x1C,0x00,0x00,0x00,0x00},
 
/* 0x2A '*' */
{0x14,0x08,0x3E,0x08,0x14,0x00,0x00,0x00},
 
/* 0x2B '+' */
{0x08,0x08,0x3E,0x08,0x08,0x00,0x00,0x00},
 
/* 0x2C ',' */
{0x00,0x50,0x30,0x00,0x00,0x00,0x00,0x00},
 
/* 0x2D '-' */
{0x08,0x08,0x08,0x08,0x08,0x00,0x00,0x00},
 
/* 0x2E '.' */
{0x00,0x60,0x60,0x00,0x00,0x00,0x00,0x00},
 
/* 0x2F '/' */
{0x20,0x10,0x08,0x04,0x02,0x00,0x00,0x00},
 
/* 0x30 '0' */
{0x3E,0x51,0x49,0x45,0x3E,0x00,0x00,0x00},
 
/* 0x31 '1' */
{0x00,0x42,0x7F,0x40,0x00,0x00,0x00,0x00},
 
/* 0x32 '2' */
{0x62,0x51,0x49,0x49,0x46,0x00,0x00,0x00},
 
/* 0x33 '3' */
{0x22,0x41,0x49,0x49,0x36,0x00,0x00,0x00},
 
/* 0x34 '4' */
{0x18,0x14,0x12,0x7F,0x10,0x00,0x00,0x00},
 
/* 0x35 '5' */
{0x2F,0x49,0x49,0x49,0x31,0x00,0x00,0x00},
 
/* 0x36 '6' */
{0x3E,0x49,0x49,0x49,0x32,0x00,0x00,0x00},
 
/* 0x37 '7' */
{0x01,0x71,0x09,0x05,0x03,0x00,0x00,0x00},
 
/* 0x38 '8' */
{0x36,0x49,0x49,0x49,0x36,0x00,0x00,0x00},
 
/* 0x39 '9' */
{0x26,0x49,0x49,0x49,0x3E,0x00,0x00,0x00},
 
/* 0x3A ':' */
{0x00,0x36,0x36,0x00,0x00,0x00,0x00,0x00},
 
/* 0x3B ';' */
{0x00,0x56,0x36,0x00,0x00,0x00,0x00,0x00},
 
/* 0x3C '<' */
{0x08,0x14,0x22,0x41,0x00,0x00,0x00,0x00},
 
/* 0x3D '=' */
{0x14,0x14,0x14,0x14,0x14,0x00,0x00,0x00},
 
/* 0x3E '>' */
{0x41,0x22,0x14,0x08,0x00,0x00,0x00,0x00},
 
/* 0x3F '?' */
{0x02,0x01,0x51,0x09,0x06,0x00,0x00,0x00},
 
/* 0x40 '@' */
{0x32,0x49,0x79,0x41,0x3E,0x00,0x00,0x00},
 
/* 0x41 'A' */
{0x00,0x7E,0x09,0x09,0x09,0x09,0x7E,0x00},
 
/* 0x42 'B' */
{0x00,0x7F,0x49,0x49,0x49,0x49,0x36,0x00},
 
/* 0x43 'C' */
{0x00,0x3E,0x41,0x41,0x41,0x41,0x22,0x00},
 
/* 0x44 'D' */
{0x00,0x7F,0x41,0x41,0x41,0x22,0x1C,0x00},
 
/* 0x45 'E' */
{0x00,0x7F,0x49,0x49,0x49,0x49,0x41,0x00},
 
/* 0x46 'F' */
{0x00,0x7F,0x09,0x09,0x09,0x09,0x01,0x00},
 
/* 0x47 'G' */
{0x00,0x3E,0x41,0x41,0x49,0x49,0x7A,0x00},
 
/* 0x48 'H' */
{0x00,0x7F,0x08,0x08,0x08,0x08,0x7F,0x00},
 
/* 0x49 'I' */
{0x00,0x41,0x41,0x7F,0x41,0x41,0x00,0x00},
 
/* 0x4A 'J' */
{0x00,0x20,0x40,0x41,0x3F,0x01,0x00,0x00},
 
/* 0x4B 'K' */
{0x00,0x7F,0x08,0x14,0x22,0x41,0x00,0x00},
 
/* 0x4C 'L' */
{0x00,0x7F,0x40,0x40,0x40,0x40,0x40,0x00},
 
/* 0x4D 'M' */
{0x00,0x7F,0x02,0x0C,0x02,0x7F,0x00,0x00},
 
/* 0x4E 'N' */
{0x00,0x7F,0x04,0x08,0x10,0x7F,0x00,0x00},
 
/* 0x4F 'O' */
{0x00,0x3E,0x41,0x41,0x41,0x41,0x3E,0x00},
 
/* 0x50 'P' */
{0x00,0x7F,0x09,0x09,0x09,0x09,0x06,0x00},
 
/* 0x51 'Q' */
{0x00,0x3E,0x41,0x51,0x21,0x5E,0x00,0x00},
 
/* 0x52 'R' */
{0x00,0x7F,0x09,0x19,0x29,0x46,0x00,0x00},
 
/* 0x53 'S' */
{0x00,0x26,0x49,0x49,0x49,0x49,0x32,0x00},
 
/* 0x54 'T' */
{0x00,0x01,0x01,0x7F,0x01,0x01,0x00,0x00},
 
/* 0x55 'U' */
{0x00,0x3F,0x40,0x40,0x40,0x40,0x3F,0x00},
 
/* 0x56 'V' */
{0x00,0x1F,0x20,0x40,0x20,0x1F,0x00,0x00},
 
/* 0x57 'W' */
{0x00,0x7F,0x20,0x18,0x20,0x7F,0x00,0x00},
 
/* 0x58 'X' */
{0x00,0x63,0x14,0x08,0x14,0x63,0x00,0x00},
 
/* 0x59 'Y' */
{0x00,0x03,0x04,0x78,0x04,0x03,0x00,0x00},
 
/* 0x5A 'Z' */
{0x00,0x61,0x51,0x49,0x45,0x43,0x00,0x00},
 
/* 0x5B '[' */
{0x00,0x7F,0x41,0x41,0x00,0x00,0x00,0x00},
 
/* 0x5C '\' */
{0x02,0x04,0x08,0x10,0x20,0x00,0x00,0x00},
 
/* 0x5D ']' */
{0x00,0x41,0x41,0x7F,0x00,0x00,0x00,0x00},
 
/* 0x5E '^' */
{0x04,0x02,0x01,0x02,0x04,0x00,0x00,0x00},
 
/* 0x5F '_' */
{0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x00},
 
/* 0x60 '`' */
{0x00,0x01,0x02,0x04,0x00,0x00,0x00,0x00},
 
/* 0x61 'a' */
{0x00,0x20,0x54,0x54,0x54,0x54,0x78,0x00},
 
/* 0x62 'b' */
{0x00,0x7F,0x48,0x48,0x48,0x48,0x30,0x00},
 
/* 0x63 'c' */
{0x00,0x38,0x44,0x44,0x44,0x44,0x28,0x00},
 
/* 0x64 'd' */
{0x00,0x30,0x48,0x48,0x48,0x48,0x7F,0x00},
 
/* 0x65 'e' */
{0x00,0x38,0x54,0x54,0x54,0x54,0x18,0x00},
 
/* 0x66 'f' */
{0x00,0x08,0x7E,0x09,0x01,0x02,0x00,0x00},
 
/* 0x67 'g' */
{0x00,0x0C,0x52,0x52,0x52,0x52,0x3E,0x00},
 
/* 0x68 'h' */
{0x00,0x7F,0x08,0x08,0x08,0x08,0x70,0x00},
 
/* 0x69 'i' */
{0x00,0x00,0x48,0x7A,0x40,0x00,0x00,0x00},
 
/* 0x6A 'j' */
{0x00,0x20,0x40,0x48,0x3A,0x00,0x00,0x00},
 
/* 0x6B 'k' */
{0x00,0x7F,0x10,0x28,0x44,0x00,0x00,0x00},
 
/* 0x6C 'l' */
{0x00,0x41,0x7F,0x40,0x00,0x00,0x00,0x00},
 
/* 0x6D 'm' */
{0x00,0x7C,0x04,0x18,0x04,0x78,0x00,0x00},
 
/* 0x6E 'n' */
{0x00,0x7C,0x08,0x04,0x04,0x78,0x00,0x00},
 
/* 0x6F 'o' */
{0x00,0x38,0x44,0x44,0x44,0x44,0x38,0x00},
 
/* 0x70 'p' */
{0x00,0x7E,0x12,0x12,0x12,0x12,0x0C,0x00},
 
/* 0x71 'q' */
{0x00,0x0C,0x12,0x12,0x12,0x12,0x7E,0x00},
 
/* 0x72 'r' */
{0x00,0x7C,0x08,0x04,0x04,0x08,0x00,0x00},
 
/* 0x73 's' */
{0x00,0x48,0x54,0x54,0x54,0x54,0x20,0x00},
 
/* 0x74 't' */
{0x00,0x04,0x3F,0x44,0x40,0x20,0x00,0x00},
 
/* 0x75 'u' */
{0x00,0x3C,0x40,0x40,0x40,0x20,0x7C,0x00},
 
/* 0x76 'v' */
{0x00,0x1C,0x20,0x40,0x20,0x1C,0x00,0x00},
 
/* 0x77 'w' */
{0x00,0x3C,0x40,0x30,0x40,0x3C,0x00,0x00},
 
/* 0x78 'x' */
{0x00,0x44,0x28,0x10,0x28,0x44,0x00,0x00},
 
/* 0x79 'y' */
{0x00,0x0C,0x50,0x50,0x50,0x50,0x3C,0x00},
 
/* 0x7A 'z' */
{0x00,0x44,0x64,0x54,0x4C,0x44,0x00,0x00},
 
/* 0x7B '{' */
{0x00,0x08,0x36,0x41,0x00,0x00,0x00,0x00},
 
/* 0x7C '|' */
{0x00,0x00,0x7F,0x00,0x00,0x00,0x00,0x00},
 
/* 0x7D '}' */
{0x00,0x41,0x36,0x08,0x00,0x00,0x00,0x00},
 
/* 0x7E '~' */
{0x10,0x08,0x08,0x10,0x08,0x08,0x00,0x00}
 
};

internal_state

struct internal_state_s internal_state

static

Singleton instance of the SSD1309 subsystem internal state.

Definition at line 406 of file ssd1309.c.

ssd1309_cmds

CMD_INFO_ts ssd1309_cmds[]

static

Table of CLI commands registered by the SSD1309 subsystem.

Registered with the command subsystem via ssd1309_cmd_client_info during ssd1309_init_subsys.

Definition at line 425 of file ssd1309.c.

                                    {
    {
        .name = "start",
        .help = "Starts the module, usage: ssd1309 start",
        .handler = ssd1309_cmd_start_handler
    },
        {
        .name = "stop",
        .help = "Stops the module, usage: ssd1309 stop",
        .handler = ssd1309_cmd_stop_handler
    },
    {
        .name = "fillrect",
        .help = "Fills a rectangle, usage: ssd1309 fillrect <x1,y1,x2,y2>",
        .handler = ssd1309_cmd_fillrect_handler
    },
    {
        .name = "clearrect",
        .help = "Clears a rectangle, usage: ssd1309 clearrect <x1,y1,x2,y2>",
        .handler = ssd1309_cmd_clearrect_handler
    },
    {
        .name = "invertrect",
        .help = "Inverts the pixels of a rectangle, usage: ssd1309 invertrect <x1,y1,x2,y2>",
        .handler = ssd1309_cmd_invertrect_handler
    },
    {
        .name = "drawtext",
        .help = "Draws text in a line, usage: ssd1309 drawtext <text> <line>",
        .handler = ssd1309_cmd_drawtext_handler
    },
    {
        .name = "clearline",
        .help = "Clears a line, usage: ssd1309 clearline <line>",
        .handler = ssd1309_cmd_clearline_handler
    },
    {
        .name = "invertline",
        .help = "Inverts a line, usage: ssd1309 invertline <line>",
        .handler = ssd1309_cmd_invertline_handler
    }
};

ssd1309_cmd_client_info

CMD_CLIENT_INFO_ts ssd1309_cmd_client_info

static

Initial value:

= {
    .cmds_ptr = ssd1309_cmds,
    .num_cmds = sizeof(ssd1309_cmds) / sizeof(ssd1309_cmds[0]),
    .name = "ssd1309",
    .log_level_ptr = &internal_state.log_level
}

Registration descriptor passed to the command subsystem.

Bundles the command table, its size, the subsystem name prefix used on the CLI, and a pointer to the runtime log-level variable.

Definition at line 475 of file ssd1309.c.

                                                    {
    .cmds_ptr = ssd1309_cmds,
    .num_cmds = sizeof(ssd1309_cmds) / sizeof(ssd1309_cmds[0]),
    .name = "ssd1309",
    .log_level_ptr = &internal_state.log_level
};