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This version (05 Jul 2013 14:53) was approved by DragosB.The Previously approved version (09 Oct 2012 09:18) is available.Diff

AD5933 - No-OS Driver for Microchip Microcontroller Platforms

Supported Devices

Evaluation Boards

Overview

The AD5933 is a high precision impedance converter system solution that combines an on-board frequency generator with a 12-bit, 1 MSPS, analog-to-digital converter (ADC). The frequency generator allows an external complex impedance to be excited with a known frequency. The response signal from the impedance is sampled by the on-board ADC and a discrete Fourier transform (DFT) is processed by an on-board DSP engine. The DFT algorithm returns a real (R) and imaginary (I) data-word at each output frequency.

Once calibrated, the magnitude of the impedance and relative phase of the impedance at each frequency point along the sweep is easily calculated. This is done off chip using the real and imaginary register contents, which can be read from the serial I2C interface.

A similar device, also available from Analog Devices, Inc., is the AD5934, a 2.7 V to 5.5 V, 250 kSPS, 12-bit impedance converter, with an internal temperature sensor and is packaged in a 16-lead SSOP.

Applications

  • Electrochemical analysis
  • Bioelectrical impedance analysis
  • Impedance spectroscopy
  • Complex impedance measurement
  • Corrosion monitoring and protection equipment
  • Biomedical and automotive sensors
  • Proximity sensing
  • Nondestructive testing
  • Material property analysis
  • Fuel/battery cell condition monitoring

01 Oct 2012 11:43 · Dragos Bogdan

The goal of this project (Microcontroller No-OS) is to be able to provide reference projects for lower end processors, which can't run Linux, or aren't running a specific operating system, to help those customers using microcontrollers with ADI parts. Here you can find a generic driver which can be used as a base for any microcontroller platform and also specific drivers for different microcontroller platforms.

Driver Description

The driver contains two parts:

  • The driver for the AD5933 part, which may be used, without modifications, with any microcontroller.
  • The Communication Driver, where the specific communication functions for the desired type of processor and communication protocol have to be implemented. This driver implements the communication with the device and hides the actual details of the communication protocol to the ADI driver.

The Communication Driver has a standard interface, so the AD5933 driver can be used exactly as it is provided.

There are three functions which are called by the AD5933 driver:

  • I2C_Init() – initializes the communication peripheral.
  • I2C_Write() – writes data to the device.
  • I2C_Read() – reads data from the device.

I2C driver architecture

The following functions are implemented in this version of AD5933 driver:

Function Description
char AD5933_Init(void) Initializes the communication peripheral.
void AD5933_SetRegisterValue(unsigned char registerAddress, unsigned long registerValue, unsigned char bytesNumber) Writes data into a register.
unsigned long AD5933_GetRegisterValue(unsigned char registerAddress, unsigned char bytesNumber) Reads the value of a register.
void AD5933_Reset(void) Resets the device.
void AD5933_SetSystemClk(char clkSource, unsigned long extClkFreq) Selects the source of the system clock.
void AD5933_SetRangeAndGain(char range, char gain) Selects the range and gain of the device.
float AD5933_GetTemperature(void) Reads the temperature from the part and returns the data in degrees Celsius.
void AD5933_ConfigSweep(unsigned long startFreq, unsigned long incFreq, unsigned short incNum) Configures the sweep parameters: Start frequency, Frequency increment and Number of increments.
void AD5933_StartSweep(void) Starts the sweep operation.
double AD5933_CalculateGainFactor(unsigned long calibrationImpedance, unsigned char freqFunction) Reads the real and the imaginary data and calculates the Gain Factor.
double AD5933_CalculateImpedance(double gainFactor, unsigned char freqFunction) Reads the real and the imaginary data and calculates the Impedance.
01 Oct 2012 15:20 · Dragos Bogdan

Downloads

Digilent Cerebot MX3cK Quick Start Guide

This section contains a description of the steps required to run the AD5933 demonstration project on a Digilent Cerebot MX3cK platform.

Required Hardware

Required Software

The AD5933 demonstration project for PIC32MX320F128H consists of three parts: the AD5933 Driver, the PmodIA Demo for PIC32MX320F128H and the PIC32MX320F128H Common Drivers.

All three parts have to be downloaded.

Hardware Setup

A PmodIA has to be connected to the J2 connector of Cerebot MX3cK development board.

Reference Project Overview

The following commands were implemented in this version of AD5933 reference project for Cerebot MX3cK board.

Command Description
help? Displays all available commands.
temperature? Displays the ambient device temperature.
startFreq= Sets the start frequency parameter. Accepted values:
1 000 .. 100 000 [Hz] - set parameter.
incFreq= Sets the frequency increment parameter. Accepted values:
0 .. 100 000 [Hz] - set parameter.
incNum= Sets the number of increments parameter. Accepted values:
0 .. 511 - set parameter.
sweepParam? Displays all three sweep parameters.
calibImpedance= Sets the calibration impedance value. Accepted values:
1 000 .. 10 000 000 [Ohm] - set impedance.
impedance? Displays the measured impedance.
currentFreq? Displays the current frequency.

Commands can be executed using a serial terminal connected to the UART1 peripheral of PIC32MX320F128H.

The following image shows a generic list of commands in a serial terminal connected to processor’s UART peripheral.

Software Project Setup

This section presents the steps for developing a software application that will run on the Digilent Cerebot MX3cK development board for controlling and monitoring the operation of the ADI part.

  • Run the MPLAB X integrated development environment.
  • Choose to create a new project.
  • In the Choose Project window select Microchip Embedded category, Standalone Project and press Next.

  • In the Select Device window choose PIC32MX320F128H device and press Next.

  • In the Select Tool window select the desired hardware tool and press Next.

  • In the Select Compiler window chose the XC32 compiler and press Next.

  • In the Select Project Name and Folder window choose a name and a location for the project.

  • After the project is created, all the downloaded source files have to be copied in the project folder and included in the project.

  • The project is ready to be built and downloaded on the development board.

05 Jul 2012 14:45

Digilent Cerebot MC7 Quick Start Guide

This section contains a description of the steps required to run the AD5933 demonstration project on a Digilent Cerebot MC7 platform.

Required Hardware

Required Software

Hardware Setup

A PmodIA has to be connected to the J6 connector of Cerebot MC7 development board.

Reference Project Overview

Following commands were implemented in this version of AD5933 reference project for Cerebot MC7 board.

Command Description
help? Displays all available commands.
temperature? Displays the ambient device temperature.
startFreq= Start frequency parameter. Accepted values: 0 - 500000Hz.
incFreq= Frequency increment parameter. Accepted values: 0 - 500000Hz.
incNum= Number of increments parameter. Accepted values: 0 - 511.
sweepParam? Displays all three sweep parameters.
calibImpedance= Calibration impedance value.Accepted values: 1 - 1000000[Ohm].
impedance? Displays the measured impedance.
currentFreq? Displays the current frequency.

Commands can be executed using a serial terminal connected to the UART1 peripheral of dsPIC33FJ128MC706A.

The following image shows a list of commands in a serial terminal connected to processor’s UART peripheral.

Software Project Setup

This section presents the steps for developing a software application that will run on the Digilent Cerebot MC7 development board for controlling and monitoring the operation of the ADI part.

  • Run the MPLAB X integrated development environment.
  • Choose to create a new project.
  • In the Choose Project window select Microchip Embedded category, Standalone Project and press Next.

  • In the Select Device window choose dsPIC33FJ128MC706A device and press Next.

  • In the Select Tool window select the desired hardware tool and press Next.

  • In the Select Compiler window chose the XC16 compiler and press Next.

  • In the Select Project Name and Folder window choose a name and a location for the project.

  • After the project is created, the source files have to be copied in the project folder and included in the project.

  • The project is ready to be built and downloaded on the development board.

16 Jul 2012 16:48

Digilent Cerebot MX3cK Quick Start Guide - chipKIT Project

This section contains a description of the steps required to run the AD5933 chipKIT demonstration project on a Digilent Cerebot MX3cK platform.

Required Hardware

Required Software

Hardware Setup

A PmodIA has to be connected to the J2 connector of Cerebot MX3cK development board.

Reference Project Overview

Following commands were implemented in this version of AD5933 chipKIT reference project for Cerebot MX3cK board.

Command Description
help? Displays all available commands.
temperature? Displays the ambient device temperature.
startFreq= Start frequency parameter. Accepted values: 0 - 500000Hz.
incFreq= Frequency increment parameter. Accepted values: 0 - 500000Hz.
incNum= Number of increments parameter. Accepted values: 1 - 511.
sweepParam? Displays all three sweep parameters.
calibImpedance= Calibration impedance value.Accepted values: 1 - 1000000[Ohm].
impedance? Displays the measured impedance.
currentFreq? Displays the current frequency.

Commands can be executed using the serial monitor.

Carriage return has to be selected as a line ending character. The required baud rate is 9600 baud.

The following image shows a list of commands in the serial monitor.

Software Project Setup

This section presents the steps for developing a chipKIT application that will run on the Digilent Cerebot MX3cK development board for controlling and monitoring the operation of the ADI part.

  • Under your Sketchbook directory create a folder called “Libraries”; this folder may already exist.
  • Unzip the downloaded file in the libraries folder.
  • Run the MPIDE environment.
  • You should see the new library under Sketch→Import Library, under Contributed.

  • Also you should see under File→Examples the demo project for the ADI library.
  • Select the ADIDriver example.

  • Select the Cerebot MX3cK board from Tools→Board.
  • Select the corresponding Serial Communication Port from Tools→Serial Port
  • The project is ready to be uploaded on the development board.

23 Jul 2012 16:51

More information

01 Jun 2012 12:17