{"id":2789,"date":"2024-09-06T11:41:54","date_gmt":"2024-09-06T11:41:54","guid":{"rendered":"https:\/\/iotthinghub.com\/?p=2789"},"modified":"2024-09-13T17:19:06","modified_gmt":"2024-09-13T17:19:06","slug":"oled-with-stm32","status":"publish","type":"post","link":"https:\/\/iotthinghub.com\/?p=2789","title":{"rendered":"OLED with STM32"},"content":{"rendered":"\n

Before interface OLED with STM32 microcontroller please go through my OLED section in OLED (SSD1306) interfacing<\/a>. In this article we interface the low cost 0.91 Inch small OLED. In our previous article we discuss about I2<\/sup>C protocol and I2<\/sup>C LCD driver. STmcu works on 3.3V & I2<\/sup>C LCD works 5V so need DC power level shifter. OLED perfectly works on 3.3V, this is one major advantage of using OLED.<\/p>\n\n\n\n

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OLED device address: 0x3C   <\/p>\n\n\n\n

For command mode value is 0x80 and for data mode value is 0x40. The user function as follow-<\/p>\n<\/div>\n<\/div>\n\n\n

\nuint8_t data_stream[3];\nextern I2C_HandleTypeDef hi2c2; \/\/I2C definition\nvoid sendcommand(uint8_t com){\ndata_stream[0]=OLED_COMMAND;\ndata_stream[1]=com;\nHAL_I2C_Master_Transmit(&hi2c2,SLAVE_ADDR_ACC<<1,data_stream,2,100); \n}\n<\/pre><\/div>\n\n
\nvoid SendChar(uint8_t data){\ndata_stream[0]=OLED_DATA;\ndata_stream[1]=data\nHAL_I2C_Master_Transmit(&hi2c2,SLAVE_ADDR_ACC<<1,data_stream,2,100);  \n}\n<\/pre><\/div>\n\n\n
Here we used hi2c2 for I2<\/sup>C number 2. Change I2<\/sup>C according to your desire. The pixel location function remain the same as-<\/p>\n\n\n
\nvoid setXY(unsigned char row, unsigned char col)\n{\n  sendcommand(0xb0+row);                \/\/set page address\n  sendcommand(0x00+(8*col&0x0f));       \/\/set low col address\n  sendcommand(0x10+((8*col>>4)&0x0f));  \/\/set high col address\n}\n<\/pre><\/div>\n\n\n
Since the display is very small and to visualized the front we use 2 pages to display a single character. For example writing \u2018B\u2019 will be-<\/p>\n\n\n
\n{0x0,0xfc,0xfc,0x8c,0x8c,0xfc,0x78,0x0,0x0,0x3f,0x3f,0x31,0x31,0x3f,0x1e,0x0}\n<\/pre><\/div>\n\n\n
So same changes in the void OLCD_write_string(int X, int Y, char *string) function as follow-<\/p>\n\n\n
\nconst char ASCCI[][16]= {0x0,0xfc,0xfc,0x8c,0x8c,0xfc,0x78,0x0,0x0,0x3f,0x3f,0x31,0x31,0x3f,0x1e,0x0};\nvoid OLCD_write_string(int X, int Y, char *string)\n{\n  uint8_t position=0;\n  while(*string)\n  {\n    setXY(X,Y+position);\n    for(uint8_t j=0;j<8;j++)\n    SendChar((char)ASCCI[*string-0x20][j]);\n    setXY(X+1,Y+position);\n    for(uint8_t j=8;j<16;j++)\n    SendChar((char)ASCCI[*string-0x20][j]);\n    *string++;\n    position++;\n  }\n}\n<\/pre><\/div>\n\n\n
Let\u2019s start with OLED with initializing with the following command and after initialize the OLED clear all the pixels by sending 0 to the pixel.<\/p>\n\n\n
\nvolatile uint8_t OLED_init[] = {0xAE,0xA6,0xAE,0xD5,0x80,0xA8,0x3F,0xD3,0x00,0x40,0x8D,0x14,0x20,0x00,0xA1,0xC8,0xDA,0x12,0x81,0xCF,0xD9,0xF1,0xDB,0x40,0xA4,0xA6,0x2E,0x20,0x00,0xAF};\nvoid init_OLED(void)\n{\n\tfor(char i=0;i<=sizeof(OLED_init);i++)\n\tsendcommand(OLED_init[i]);\n}\n<\/pre><\/div>\n\n\n
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Download the driver file and let\u2019s start with OLED.<\/p>\n<\/div>\n\n\n\n
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.91″ OLED Driver<\/a><\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
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