STM8 I²c's Learning

STM8 's I²c interface


1, I²c mode selection
The interface has 4 modes: from the device transmission mode, from the device receiving mode, the main device sending mode, the main device receiving mode


。
By default, the I²c module works in slave mode. The interface automatically switches from slave mode to main mode after the starting condition is generated


When the quorum fails or when a stop signal is sent, the switch from mode to slave mode.


2. Communication process
In main mode, the I²c interface initiates data transfer and generates a clock signal. Serial data transfer always starts with the starting condition and


Ends with a stop condition. Both the start condition and the stop condition are generated by software control in the main mode.


Related function Registers
1, i²c Control register 1 (I2C_CR1)
2, I²c control Register 2 (I2C_CR2)
3, I²c frequency register (I2C_FREQR)
allowable clock range in 1-24mhz
4, I²c self address Register LSB (I2C_OARL)
5, I²c self-address register MSB (I2c_oarh)
6, I²C Data Register (I2C_DR)
7, i²c Status Register 1 (I2C_SR1)
8, i²c Status Register 2 (I2C_SR2)
9, i²c Status Register 3 (I2C_SR3)
10. I2c_itr I²c Interrupt Register
11, I²c clock Control register low part (I2C_CCRL)
12, I²c clock Control Register high part (I2C_CCRH)




Initialization of the SI7020
void Sht20_gpio_init (void)
{
Gpio_init (I2c_sda_port, I2c_sda_pin, gpio_mode_in_pu_no_it);
Gpio_init (I2c_scl_port, I2c_scl_pin, gpio_mode_in_pu_no_it);
Sda_output ();
Scl_output ();
}


#define SDA_OUTPUT () do{i2c_sda_port->ddr |=i2c_sda_pin;} while (0)
#define SCL_OUTPUT () do{i2c_scl_port->ddr |=i2c_scl_pin;} while (0)