Analog Comparator Interface Controller - Example Using Comparison Interrupt

Purpose

This example demonstrates how to use the ACIFC module and its interrupt to get a comparison result from a pair of inputs.

Requirements

This example has been tested on the following evaluation kits:

• SAM4L EK
• SAM4L Xplained Pro
• SAM4L8 Xplained Pro

Description

This example demonstrates usage of the ACIFC module. The device pins PA06 and PA07 are selected as inputs. The connection can be as follows:

For SAM4L EK

• PA06(J100.2) – ADC SENSOR VBAT(J105.1)
• PA07(J4.4) – VCC(J4.10)

Or

• PA06(J100.2) – ADC SENSOR VBAT(J105.1)
• PA07(J4.4) – GND(J4.9)

For SAM4L/SAM4L8 Xplained Pro:

• PA06(EXT3/PIN9) – GND(EXT3/PIN19)
• PA07(EXT2/PIN3) – VCC(EXT2/PIN20)

Or

• PA06(EXT3/PIN9) – VCC(EXT3/PIN20)
• PA07(EXT2/PIN3) – GND(EXT2/PIN19)

Main Files

• acifc.c: Analog Comparator Interface Controller driver
• acifc.h: Analog Comparator Interface Controller driver header file
• acifc_example.c: Analog Comparator Interface Controller example application

Compilation Information

This software is written for GNU GCC and IAR Embedded Workbench® for Atmel®. Other compilers may or may not work.

Usage

1. Build the program and download it into the evaluation board.
2. On the computer, open, and configure a terminal application (e.g., HyperTerminal on Microsoft® Windows®) with these settings:
   • 115200 baud
   • 8 bits of data
   • No parity
   • 1 stop bit
   • No flow control
3. Start the application.
4. In the terminal window, the following text should appear:

   * -- ACIFC IRQ Example xxx --
   * -- xxxxxx-xx
   * -- Compiled: xxx xx xxxx xx:xx:xx -- 

5. The application will output a different message if the voltage on pin. PA06 is lower or higher than the voltage on pin PA07 :

   -ISR- Voltage Comparison Result: ACAP0 > ACAN0 

   or

   -ISR- Voltage Comparison Result: ACAP0 < ACAN0