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Platform - IADC High-speed Mode functionality

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Overview

This project shows how to use the IADC in high-speed mode on the EFM32PG23 Pro Kit (BRD2504A) board. IADC is used for oversampling the analog signal on the SMA connector with the high-speed feature. In the high-speed mode, the IADC clock speed is doubled to 20 MHz (10 MHz in the normal mode). This feature is useful in applications, that require high-speed of sampling data.

Gecko SDK Suite version

  • GSDK v4.4.3

Hardware Required

Connections Required

Connect the board via a USB Type-C cable to your PC to flash the example.

board

Setup

To test this application, you can either create a project based on an example project or start with an empty example project.

Create a project based on an example project

  1. Make sure that this repository is added to Preferences > Simplicity Studio > External Repos.

  2. From the Launcher Home, add the BRD2504A to My Products, click on it, and click on the EXAMPLE PROJECTS & DEMOS tab. Find the example project filtering by iadc and high-speed.

  3. Click the Create button on the "Platform - IADC High-speed Mode" example. Example project creation dialog pops up -> click Finish and Project should be generated.

    Create_project

  4. Build and flash this example to the board.

Start with an empty example project

  1. Create an Empty C Project project for your hardware using Simplicity Studio 5.

  2. Copy all files in the inc and src folders into the project root folder (overwriting the existing file).

  3. Open the .slcp file. Select the SOFTWARE COMPONENTS tab and install the software components:

    • [Platform] → [Peripheral] → [ADC]
    • [Platform] → [Peripheral] → [LDMA]

  4. Build and flash the project to your device.

How It Works

This project demonstrates using the IADC peripheral for oversampling and high-speed features to acquire 12-bit resolution conversion results. The firmware utilizes emlib_iadc structures and functions to properly configure the peripheral and employ the appropriate offset corrections.

Once conversions are started, the IADC converts continuously and the LDMA transfers the results into an array. The IADC is clocked from the 39 MHz HFXO, and the ADC prescaler divides this by 2. The sampling rate is 1.95 Msps.

Testing

To test the project, follow the below steps:

  1. Update the firmware of your board from the Simplicity Launcher (if necessary).

  2. Build the project and flash the image to the EFM32PG23 Pro Kit board.

  3. Open the Simplicity Debugger and add the singleBuffer variable in the iadc_single.c file to the Expressions Window.

  4. Apply a voltage to the IADC input pin (SMA connector)

  5. Observe the singleBufffer array as it will display the ADC results 12-bit result with 1024 samples. The singleBuffer array is VDD referenced and scaled 0-4095. The picture below illustrates the singleBufffer with the VMCU value as input. buffer_debugger

  6. To observe the output pin pulsing, use the PA5 pin on the EFM32PG23 Pro Kit board. An edge (including rising or falling) is generated every 1024 samples after about 525 microseconds (uS). output_pulse

  7. Suspend the debugger, observe the measured voltage change in the Expressions Window and how it responds to different voltage values on the corresponding pins.