Using U8g2 with STM32
- Download the repository for U8g2 from GitHub here https://github.com/olikraus/u8g2
- Copy the “csrc” folder within the downloaded and extracted repo into “Src” folder in STM32 project
- Rename the folder “U8g2”
- Head to “mui_U8g2.h” and add
#include "u8g2.h"- Add to user includes
#include "u8g2/u8g2.h"- Add to private user code
This is the SPI GPIO Implementation of the callback function with PA04 = CS, PA01 = DC/RS and PA00 = RESET. I2C implementation would differ but have similar structure.
uint8_t u8g2_gpio_and_delay_stm32(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, U8X8_UNUSED void *arg_ptr)
{
switch (msg)
{
case U8X8_MSG_GPIO_AND_DELAY_INIT:
HAL_Delay(1);
break;
case U8X8_MSG_DELAY_MILLI:
HAL_Delay(arg_int);
break;
case U8X8_MSG_GPIO_CS:
/* Insert codes for SS pin control */
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, arg_int);
break;
case U8X8_MSG_GPIO_DC:
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, arg_int);
break;
case U8X8_MSG_GPIO_RESET:
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_0, arg_int);
break;
}
return 1; // command processed successfully.
}
- Add to user code in main function
u8g2_t u8g2;- Add the SPI initialization to user code
uint8_t u8x8_byte_4wire_hw_spi(u8x8_t *u8x8, uint8_t msg, uint8_t arg_int, void *arg_ptr)
{
switch (msg)
{
case U8X8_MSG_BYTE_SEND:
HAL_SPI_Transmit(&hspi1, (uint8_t *) arg_ptr, arg_int, 10000);
break;
case U8X8_MSG_BYTE_INIT:
break;
case U8X8_MSG_BYTE_SET_DC:
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_1, arg_int);
break;
case U8X8_MSG_BYTE_START_TRANSFER:
break;
case U8X8_MSG_BYTE_END_TRANSFER:
break;
default:
return 0;
}
return 1;
}
- Finally initialize the library for use
u8g2_Setup_st7565_erc12864_f(&u8g2, U8G2_R0, u8x8_byte_4wire_hw_spi, u8g2_gpio_and_delay_stm32);
u8g2_InitDisplay(&u8g2); // send init sequence to the display, display is in sleep mode after this,
u8g2_SetPowerSave(&u8g2, 0); // wake up display
u8g2_SetContrast(&u8g2, 10);
- Write your own code before and within the while loop. An example is show below
u8g2_ClearBuffer(&u8g2);
// u8g2_SetBitmapMode(&u8g2,1);
// u8g2_DrawBitmap(&u8g2, 0, 0, bitmap_height, bitmap_width, bitmap);
// u8g2_DrawXBM(&u8g2, 0, 0, 58, 64, GR);
u8g2_SendBuffer(&u8g2);
HAL_Delay(1500);
u8g2_ClearBuffer(&u8g2);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, 1);
HAL_Delay(500);
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_13, 0);
HAL_Delay(500);
u8g2_FirstPage(&u8g2);
do
{
int yCoord = 11;
while (yCoord < 39)
{
u8g2_DrawBox(&u8g2, 116, yCoord, 10, 6);
yCoord += 8;
}
u8g2_DrawFrame(&u8g2, 116, 43, 10, 6);
u8g2_DrawCircle(&u8g2, 8, 9, 4, U8G2_DRAW_ALL);
u8g2_DrawCircle(&u8g2, 8, 20, 4, U8G2_DRAW_ALL);
u8g2_DrawCircle(&u8g2, 8, 31, 4, U8G2_DRAW_ALL);
u8g2_DrawCircle(&u8g2, 8, 42, 4, U8G2_DRAW_ALL);
u8g2_DrawDisc(&u8g2, 8, 53, 4, U8G2_DRAW_ALL);
u8g2_SetFont(&u8g2, AEB_24_font);
u8g2_DrawStr(&u8g2,42, 40, "15");
u8g2_SetFont(&u8g2, u8g2_font_6x10_tr);
u8g2_DrawStr(&u8g2,67, 31, "km/h");
u8g2_DrawStr(&u8g2,50, 57, "09:23");
u8g2_DrawStr(&u8g2, 110, 10, "80%");
u8g2_DrawXBM(&u8g2, 105, 50, 16, 14, epd_bitmap_plug_circle_bolt_solid_resize);
} while (u8g2_NextPage(&u8g2));
The official font for Goliath Robotics is Adelle Regular.
Use a website to convert image to cpp.
Using any custom font
First download the font which comes usually zipped and extract it. In the zipped file you would usually find it in a format apart from bdf which we are gauging. Especially with Adelle Regular which is a font from Adobe, it comes in otf files. OpenType Font was developed by Adobe and Microsoft for saving their font types. Use Vertopal Converter or any convenient converter to change the font from otf to fon. Change the conversion settings to the correct pixel height that would be printed on the screen. Fony is a used to convert fon file typed to bdf. Open fon file with Fony and export as bdf. Convert the bdf into c code that can be placed in the library by using the command
- Move the bdf file into the same directory as the tool which is in:
...u8g2\tools\font\bdfconv
- Run the following command in the terminal opened from that directory
bdfconv -f 1 -m '32-255' -n fontname -o myfont.c myfont.bdf
where; - “-f 1” generates a u8g2 font. - “-m ‘32-255’” selects unicode 32 to 255. On Windows, please use double quotes: -m “32-255” - “-n fontname”: This is the name of the font in C/C++/Ino files. - “-o myfont.c”: The font array will be stored in this file. - “myfont.bdf”: The input file with the font data (bdf format).
- Open the generated file in the same directory and copy the entire text.
- look for the file ../u8g2_fonts.c in your workspace in STM32 IDE with your copied text looking something like this:
const uint8_t font_name[5626] U8G2_FONT_SECTION("font_name") =
"\340\0\4\4\5\5\4\5\6\32\36\0\372\22\373\22\374\2\304\6\235\25\335 \6\0 ,\1!\17E"
"&<\341\7)\210\214\33\241b\4\0\42\11\311\344V\201\4\276 #\34\255%|g\310\250!cX"
",Y$d\324\220\61,\270\31\61l\304\60!\203\0$\31kfk\247X\251\24n\320$C\243$"
...;
- Add the copied text at the bottom of the file
- Add the array declaration in u8g2.h to the existing declarations as;
extern const uint8_t font_name[] U8G2_FONT_SECTION("font_name");
- Use the font like any other u8g2 font (if the character is available in the font)
https://forum.arduino.cc/t/u8g2-custom-font-tutorial-with-fony/686061
Todo
Repurpose A2 and A3 from the screen GPS antennas Save memory by taking only alphanums we need
PWM for the screen brightness