Firmware Course Review - 03.1. I2C

1. Title

LCD Display using I2C

2. Category

"STM32", "Firmware"

 

3. Key Concepts

"I2C"
In STM32, using the HAL_I2C_Master_Transmit function to send control signal to Hardware. It sends data by SDA to a specified address in specified buffer size synchronized by the clock signal on the SCL.

• SDA (Serial Data): This is the line used for transferring the actual data between the master and slave devices.
• SCL (Serial Clock): This is the clock line used to synchronize the data transmission, controlling when each bit of data is sent or received.
  
  

1: SDA 2:SCL

 

4. Code Review

 

#define I2C_LCD_ADDRESS (0x27 << 1)
unsigned char lcd_test[4] = {'9','7',0};

void i2c_lcd_main(void)
{
  while (1)
  {
       while(HAL_I2C_Master_Transmit(&hi2c1, I2C_LCD_ADDRESS,
             lcd_test, 2, 100)!=HAL_OK){
          //HAL_Delay(1);
       }
       HAL_Delay(1000);
  }
}

Defines an I2C address for the LCD (0x27 shifted by 1) and initializes a test data array (lcd_test) with values '9', '7', and a null terminator.
The i2c_lcd_main function repeatedly sends the first two bytes of lcd_test to the LCD via I2C using the HAL_I2C_Master_Transmit function, with a 1-second delay between transmissions.

 

5. Testing and Debugging

* Testing Tools: STM32 CUBE IDE, NUCLEO-F411RE, Oscilloscope