References

  1. AVR317: Using the USART on the ATmega48/88/168 as a SPI master
  2. AVR054: Run-time calibration of the internal RC oscillator via the UART
  3. STK600 Routing Cards and Socket Cards
  4. ATmega324PB Xplained Pro User Guide
  5. Atmel Studio - Programming Dialogue
  6. ATTINY104-XNANO User Guide