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AD7980-適用于微芯片微控制器平臺的無操作系統(tǒng)驅(qū)動程序

2512819 2021-04-21 | pdf | 1.98MB | 次下載 | 3積分

資料介紹

This version (27 Jan 2021 23:02) was approved by Robin Getz.The Previously approved version (11 Jan 2021 15:12) is available.

AD7980 - No-OS Driver for Microchip Microcontroller Platforms

Supported Devices

AD7980

Evaluation Boards

EVAL-AD7980-PMDZ

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

01 Oct 2012 12:04 · 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 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

01 Oct 2012 15:06 · Dragos Bogdan

HW Platform(s):

Digilent Cerebot MX3cK (Digilent)
Cerebot MC7 (Digilent)

Downloads

AD7980 DSPIC33 Driver
AD7980 chipKIT Driver
AD7980 Driver: https://github.com/analogdevicesinc/no-OS/tree/master/drivers/adc/ad7980
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 Software

MPLAB X Integrated Development Environment
MPLAB XC32 compiler
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.

05 Jul 2012 14:45