Input-output

The System of Input-Output is the bridge between drivers and physical devices.
Main function of system: control of work of peripheral interfaces.

The system serves the following interfaces:
  1. TWI (two-wire serial interface);
  2. SPI (serial peripheral interface);
  3. I2C;
  4. UART/USART.

The system provides the following operations of input-output:
- Initialization of the interface;
- Initialization of an exchange;
- Data transfer;
- Execution of operations of reading and writing of the low-level;
- Handling interruptions
- Control of an exchange: start, stop, expectation etc;
- The access to the status of an exchange;
- etc.

At the end of an exchange, control comes back into the driver of the device or into the program - initiator
of an exchange.