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This version (27 Jan 2021 23:02) was approved by Robin Getz.The Previously approved version (11 Jan 2021 15:12) is available.
Table of Contents
AD7980 - No-OS Driver for Microchip Microcontroller Platforms
Supported Devices
Evaluation Boards
Overview
The AD7980 is a 16-bit, successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, VDD. It contains a low power, high speed, 16-bit sampling ADC and a versatile serial interface port. On the CNV rising edge, it samples an analog input IN+ between 0 V to REF with respect to a ground sense IN−. The reference voltage, REF, is applied externally and can be set independent of the supply voltage, VDD. Its power scales linearly with throughput.
The SPI-compatible serial interface also features the ability, using the SDI input, to daisy-chain several ADCs on a single, 3-wire bus and provides an optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic, using the separate supply VIO.
The AD7980 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with operation specified from −40°C to +125°C.
The AD7980-EP supports defense and aerospace applications (AQEC)
Applications
- Battery-powered equipment
- Communications
- ATE
- Data acquisitions
- Medical instruments
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 AD7980 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 AD7980 driver can be used exactly as it is provided.
There are three functions which are called by the AD7980 driver:
- SPI_Init() – initializes the communication peripheral.
- SPI_Write() – writes data to the device.
- SPI_Read() – reads data from the device.
SPI driver architecture
The following functions are implemented in this version of AD7980 driver:
| Function | Description |
|---|---|
| char AD7980_Init(void) | Initializes the communication peripheral. |
| unsigned short AD7980_Conversion(void) | Initiates conversion and reads data. |
| float AD7980_ConvertToVolts(unsigned short rawSample, float vRef) | Converts a 16-bit raw sample to volts. |
This version of AD7980 driver uses the CS Mode 4-Wire, without Busy Indicator mode; the device has to be connected to an SPI-compatible digital host as following:
- The AD7980 CNV signal (C2 on the oscilloscope) has to be connected to the SPI MOSI signal.
- The AD7980 SDI signal (C1 on the oscilloscope) has to be connected to the SPI CS signal (Chip Select has to be controlled manually).
- The AD7980 SCK signal (C4 on the oscilloscope) has to be connected to the SPI SCK signal.
- The AD7980 SDO signal (C3 on the oscilloscope) has to be connected to the SPI MISO signal.
Signals generated by the driver on the SPI port
HW Platform(s):
Downloads
- EVAL-AD7980-PMDZ Demo for PIC32MX320F128H: https://github.com/analogdevicesinc/no-OS/tree/master/Microchip/PIC32MX320F128H/PmodAD4
- PIC32MX320F128H Common Drivers: https://github.com/analogdevicesinc/no-OS/tree/master/Microchip/PIC32MX320F128H/Common
Digilent Cerebot MX3cK Quick Start Guide
This section contains a description of the steps required to run the AD7980 demonstration project on a Digilent Cerebot MX3cK platform.
Required Hardware
Required Software
- The AD7980 demonstration project for PIC32MX320F128H.
The AD7980 demonstration project for PIC32MX320F128H consists of three parts: the AD7980 Driver, the EVAL-AD7980-PMDZ Demo for PIC32MX320F128H and the PIC32MX320F128H Common Drivers.
All three parts have to be downloaded.
Hardware Setup
A has to be connected to the JE connector of Cerebot MX3cK development board.
- If you want to use AVDD > DVDD (= 3.3V) then JP3 on PmodAD4 must be removed. The range for AVDD is 3.0V ≤ AVDD ≤ 5.5V.
Reference Project Overview
The following commands were implemented in this version of AD7980 reference project for Cerebot MX3cK board.
| Command | Description |
|---|---|
| help? | Displays all available commands. |
| voltage? | Initiates a conversion and displays the captured voltage. |
| register? | Initiates a conversion and displays the data register in decimal format. |
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.
- The reference voltage for the AD7980 is 2.5V.
- If you want to use another reference voltage, you will need to modify the constant VREF value in ‘PmodAD4 Demo’. The range for VREF is 2.4V ≤ VREF ≤ 5.1V.
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.
Digilent Cerebot MC7 Quick Start Guide
This section contains a description of the steps required to run the AD7980 demonstration project on a Digilent Cerebot MC7 platform.
Required Hardware
Required Software
Hardware Setup
A EVAL-AD7980-PMDZ has to be connected to the JB connector of Cerebot MC7 development board.
Reference Project Overview
Following commands were implemented in this version of AD7980 reference project for Cerebot MC7 board.
| Command | Description |
|---|---|
| help? | Displays all available commands. |
| voltage? | Initiates a conversion and displays the captured voltage. |
| register? | Initiates a conversion and displays the data register in decimal format. |
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.
Digilent Cerebot MX3cK Quick Start Guide - chipKIT Project
This section contains a description of the steps required to run the AD7980 chipKIT demonstration project on a Digilent Cerebot MX3cK platform.
Required Hardware
Required Software
Hardware Setup
A EVAL-AD7980-PMDZ has to be connected to the JE connector of Cerebot MX3cK development board.
Reference Project Overview
Following commands were implemented in this version of AD7980 chipKIT reference project for Cerebot MX3cK board.
| Command | Description |
|---|---|
| help? | Displays all available commands. |
| voltage? | Initiates a conversion and displays the captured voltage. |
| register? | Initiates a conversion and displays the raw data in decimal format. |
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.
More information
- Example questions:
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resources/tools-software/uc-drivers/microchip/ad7980.txt · Last modified: 27 Jan 2021 23:00 by Robin Getz