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This version (26 Jul 2013 08:39) was approved by DragosB.The Previously approved version (09 Oct 2012 09:12) is available.Diff

AD5628 - No-OS Driver for Microchip Microcontroller Platforms

Supported Devices

Evaluation Boards

Overview

The AD5628 device is a low power, octal, 12-bit, buffered voltage-output DAC. The device operates from a single 2.7 V to 5.5 V supply and is guaranteed monotonic by design. The AD5628 is available in both a 4 mm × 4 mm LFCSP and a 16-lead TSSOP.

The AD5628 has an on-chip reference with an internal gain of 2. The AD5628-1 has an 1.25 V 5 ppm/°C reference, giving a full-scale output range of 2.5 V; the AD5628-2, has a 2.5 V 5 ppm/°C reference, giving a full-scale output range of 5 V. The on-board reference is off, at power-up, allowing the use of an external reference. The internal reference is enabled via a software write.

The part incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V and remains powered up at this level until a valid write takes place. The part contains a power-down feature that reduces the current consumption of the device to 400 nA at 5 V and provides software-selectable output loads while in power-down mode for any or all DAC channels.

The outputs of all DACs can be updated simultaneously using the LDAC function, with the added functionality of user-selectable DAC channels to simultaneously update. There is also an asynchronous CLR that updates all DACs to a user-programmable code—zero scale, midscale, or full scale.

The AD5628 utilizes a versatile 3-wire serial interface that operates at clock rates of up to 50 MHz and is compatible with standard SPI®, QSPI™, MICROWIRE™, and DSP interface standards. The on-chip precision output amplifier enables rail-to-rail output swing.

Applications

  • Process control
  • Portable battery-powered instruments
  • Digital gain and offset adjustment
  • Programmable voltage and current sources
  • Programmable attenuators

01 Oct 2012 10:41 · 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 AD5628 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 AD5628 driver can be used exactly as it is provided.

There are three functions which are called by the AD5628 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 AD5628 driver:

Function Description
char AD5628_Init(void) Resets the device and performs several initializations.
void AD5628_PowerMode(unsigned char pwrMode, unsigned char channel) Sets the device in a specific power mode.
void AD5628_Reset(void) Resets the device.
void AD5628_SetInputRegister(unsigned long registerValue) Writes a 32-bit data-word to the Input Register of the device.
01 Oct 2012 15:15 · Dragos Bogdan

Downloads

Digilent Cerebot MX3cK Quick Start Guide

This section contains a description of the steps required to run the AD5628 demonstration project on a Digilent Cerebot MX3cK platform.

Required Hardware

Required Software

The AD5628 demonstration project for PIC32MX320F128H consists of three parts: the AD5628 Driver, the PmodDA4 Demo for PIC32MX320F128H and the PIC32MX320F128H Common Drivers.

All three parts have to be downloaded.

Hardware Setup

A PmodDA4 has to be connected to the JE connector of Cerebot MX3cK development board.

Reference Project Overview

The following commands were implemented in this version of AD5628 reference project for Cerebot MX3cK board.

Command Description
help? Displays all available commands.
mode= Selects a mode of operation for selected channel. Accepted values:
channel:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.
mode:
0 - Normal operation.
1 - 1KOhm to GND(Power down mode).
2 - 100KOhm to GND(Power down mode).
3 - Three-state(Power down mode).
mode? Displays the selected mode of operation for the selected channel. Accepted values:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.
voltage= Sets the output voltage for the selected channel. Accepted values:
channel:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.
output voltage:
0 .. 2500 - Desired output voltage in milivolts.
voltage? Displays the output voltage of the selected channel. Accepted values:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.
register= Writes the value into the DAC register of the selected channel. Accepted values:
channel:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.
register value:
0 .. 4095 - The value written to the DAC.
register? Displays the value written in the DAC register of the selected channel. Accepted values:
0 .. 7 - Channel A .. H(one channel)
15 - All channels.

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 AD5628 demonstration project on a Digilent Cerebot MC7 platform.

Required Hardware

Required Software

Hardware Setup

A PmodDA4 has to be connected to the JB connector of Cerebot MC7 development board.

Reference Project Overview

Following commands were implemented in this version of AD5628 reference project for Cerebot MC7 board.

Command Description
help? Displays all available commands.
mode= Selects a mode of operation for the current channel. Accepted values: 0 – 3.
mode? Displays the selected mode of operation for the current channel.
channel= Selects the channel that will be affected by the other commands. Accepted values: 0 – 7 (one channel) or 15 (all channels).
channel? Displays the selected channel.
voltage= Sets the output voltage for the current voltage. Accepted values: 0 – 2.5 (volts).
voltage? Displays the output voltage of the current voltage.
register= Writes the value into the Input Register of the current channel. Accepted values: 0 – 4095.
register? Displays the value written in the Input Register of the current channel.

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 AD5628 chipKIT demonstration project on a Digilent Cerebot MX3cK platform.

Required Hardware

Required Software

Hardware Setup

A PmodDA4 has to be connected to the JE connector of Cerebot MX3cK development board.

Reference Project Overview

Following commands were implemented in this version of AD5628 chipKIT reference project for Cerebot MX3cK board.

Command Description
help? Displays all available commands.
mode= Selects a mode of operation for the current channel. Accepted values: 0 – 3.
mode? Displays the selected mode of operation for the current channel.
channel= Selects the channel that will be affected by the other commands. Accepted values: 0 – 7 (one channel).
channel? Displays the selected channel.
voltage= Sets the output voltage for the current voltage. Accepted values: 0 – 2.5 (volts).
voltage? Displays the output voltage of the current voltage.
register= Writes the value into the Input Register of the current channel. Accepted values: 0 – 4095.
register? Displays the value written in the Input Register of the current channel.

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

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