ADC and Power Optimization Solution 5 EVSYS

INTRODUCTION This example is the solution for Assignment 5: ADC EVSYS from the ADC and Power Optimization on tinyAVR 0- and 1-series, and megaAVR 0-series training manual. In this assignment, the RTC overflow event signal, instead of the RTC overflow interrupt, will be used to trigger an ADC conversion. This will further reduce the power consumption as this approach avoids RTC interrupt triggering CPU when the device is in SLEEP STANDBY mode.

The application code is written for ATtiny817 Xplained Pro, but is compatible for all devices in the tinyAVR 0-/1-series and megaAVR 0-series.

PERIPHERALS INVOLVED Analog to Digital Converter (ADC) Universal Synchronous and Asynchronous Receiver and Transmitter (USART) Real Time Counter (RTC) CPUINIT SLPCTRL EVENT SYSTEM RELATED DOCUMENTS / APPLICATION NOTES This application is described in the following application notes:

ADC and Power Optimization on tinyAVR 0- and 1-series, and megaAVR 0-series SUPPORTED EVALUATION KIT ATtiny817 Xplained Pro INTERFACE SETTINGS CPU CLK 5MHz ADC 8-bit resolution ADC input pin 10 Reference selection (VREF): VDD PRESCALAER: 8 WINCM: Below Window WINHT: 0 WINLT: 80 WCMP Interrupt enabled USART No parity 8-bit character size 1 stop bit 96000 baud-rate PB2 set as TX transmission pin RTC PRESCALAER: 32 PER: 512 CPUINIT

SLPCTRL

EVENT SYSTEM ASYNCHCH0: Real Time Counter overflow ASYNCUSER1: Asynchronous Event Channel 0 Potmeter Connect potmeter to the analog input pin, PB1, and VDD and GND RUNNING THE DEMO Press DOWNLOAD SELECTED EXAMPLE in the example browser, or click EXPORT PROJECT -> DOWNLOAD PACK from within START and save the .atzip file Import .atzip file into Atmel Studio 7, by clicking File->Import->Atmel Start Project. Build the application and program the device. Press Start without debugging or use CTRL+ALT+F5 hotkeys to run the application. The ADC data is continuously printed to the terminal once every 500ms. By rotating the potmeter knob, the voltage input to ADC input pin changes. And the ADC data to Data Visualizer changes accordingly, in range from 0 to 0xFF. The current consumption of this assignment is shown in power analysis window. It has been further reduced from the previous assignment.