4.1 MCU and Peripheral Configuration

  • CPU clock: 10 MHz in Active mode, 5 MHz in Standby sleep mode
  • Peripherals used:
    • ADC in differential mode
      • PGA set to 16x gain
      • ADC MUXPOS input channel is AIN9: pin PB4
      • ADC MUXNEG input channel is AIN5: pin PA5
      • ADC reference voltage: 1.024V
      • ADC clock: 2.5 MHz (FCPU/2)
      • ADC triggered trough the Event System
    • RTC/PIT:
      • RTC clock running at 1024 Hz
      • PIT/256 connected to ADC trough the event system. The conversion trigger rate is 4 Hz.
      • PIT/256 connected to the event out pin PB7. LED0 toggle rate is 4 Hz when movement is detected.
      • PIT/1024 connected to the event out pin PB7. LED0 toggle rate is 1 Hz during warm-up.
    • Event System
      • Connects PIT to ADC
      • Connects PIT to LED0
    • USART0:
      • TXD: PB2
      • RXD: PB3
      • Baud rate: 115200, ADC result is sent to the serial terminal