I2C or Inter-IC (integrated circuit) bus
Characteristics Of The I2C-Bus
The I2C-bus is for bidirectional, two-line communication between different ICs or modules. The two lines are a serial data line (SDA) and a serial clock line (SCL). Both lines must be connected to a positive supply via a pull-up resistor. Data transfer may be initiated only when the bus is not busy.
Bit transfer
One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during the HIGH period of the clock pulse as changes in the data line at this time will be interpreted as a control signal.
Start and stop conditions
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW transition of the data line, while the clock is HIGH, is defined as the start condition (S). A LOW-to-HIGH transition of the data line while the clock is HIGH, is defined as the stop condition (P).
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