1.2 AC Sleepwalking

This example application shows how to use the AC Peripheral library to perform a single shot comparison in standby sleep mode periodically and wake up the device at the end of a successful comparison.

Description

Single shot conversion is triggered by RTC compare event. Generation of a trigger and compare operation are done while the CPU is in the standby sleep mode. AC generates the interrupt on the end of the comparison which wakes the CPU.

Downloading and Building the Application

To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.

Path of the application within the repository is apps/ac/ac_sleepwalk_singleshot/firmware.

To build the application, refer to the following table and open the project using its IDE.

Project NameDescription
sam_c21n_xpro.XMPLABX project for SAMC21N Xplained Pro Evaluation Kit

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameDescription
sam_c21n_xpro.XSAMC21N Xplained Pro Evaluation Kit

Setting Up SAMC21N Xplained Pro Evaluation Kit

  • Connect a voltage below VDD to pin 3 of the ‘VREF connector’ (6-pin)
  • Connect the Debug USB port on the board to the computer using a micro USB cable

Running the Application

  1. Open the Terminal application (Ex.:Tera term) on the computer
  2. Connect to the EDBG Virtual COM port and configure the serial settings as follows:
    • Baud : 115200
    • Data : 8 Bits
    • Parity : None
    • Stop : 1 Bit
    • Flow Control : None
  3. Build and Program the application using its IDE
  4. Observe output message in console as follows:
  5. Console displays the message stating whether voltage at AC input is lower or greater than the internal bandgap voltage (1.1V)
  6. LED toggles when comparison is done
Below table shows the AC input pin and LED name for the board:
BoardAC Input PinLED Name
SAMC21N Xplained Pro Evaluation KitPin 3 of the ‘VREF connector’ (6-pin)LED0