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CED1Z FPGA Project for AD7621 with Nios driver


This document presents the steps to setup an environment for using the EVAL-AD7621EDZ evaluation board together with the EVAL-CED Converter Evaluation and Development (CED) Board, the Nios II Embedded Development Suite (EDS) and the Micrium µC-Probe run-time monitoring tool. Below is presented a picture of the EVAL-AD7621 Evaluation Board with the CED1 board.

The CED1Z board is intended for use in evaluation, demonstration and development of systems using Analog Devices precision converters. It provides the necessary communications between the converter and the PC, programming or controlling the device, transmitting or receiving data over a USB link.

The AD7621 is a 16-bit, 1 MSPS, charge redistribution SAR,analog-to-digital converter that operates from a single 5 V power supply. It contains a high speed 16-bit sampling ADC, a resistor input scaler that allows various input ranges, an internal conversion clock, error correction circuits, and both serial and parallel system interface ports. The AD7621 is hardware factory-calibrated and is comprehensively tested to ensure such AC parameters as signal-to-noise ratio (SNR) and total harmonic distortion (THD), in addition to the more traditional DC parameters of gain, offset, and linearity. It features a very high sampling rate mode (Warp), a fast mode (Normal) for asynchronous conversion rate applications, and, for low power applications, a reduced power mode (Impulse) where the power is scaled with the throughput. It is fabricated using Analog Devices’ high performance, 0.6 micron CMOS process and is available in a 48-lead LQFP and a tiny 48-lead LFCSP, with operation specified from –40C to +85C.

The EVAL-AD7621EDZ is a fully featured evaluation kit for the AD7621. This board operates in stand alone mode or in conjunction with the Converter Evaluation and Development board, EVAL-CED1Z . When operated with the Converter Evaluation and Development board, software is provided enabling the user to perform detailed analysis of the ADC's performance.

More information

Getting Started

The first objective is to ensure that you have all of the items needed and to install the software tools so that you are ready to create and run the evaluation project.

Hardware Items

Below is presented the list of required hardware items:

Software Tools

Below is presented the list of required software tools:

The Quartus II design software and the Nios II EDS is available via the Altera Complete Design Suite DVD or by downloading from the web.

The Micrium uC/Probe Trial version is available via download from the web at Note: After installation add to the “Path” system variable the entry “%QUARTUS_ROOTDIR%\bin\“ on the third position in the list.


Extract the Lab Files

Create a folder called “ADIEvalBoard” on your PC and extract the archive to this folder. Make sure that there are NO SPACES in the directory path. After extracting the archive the following folders should be present in the ADIEvalBoard folder: FPGA, Hdl, NiosCpu, Software, ucProbe

Folder Description
FPGA Contains all the files necessary to program the CED1Z board in order to evaluate the ADC. By executing the script program_fpga.bat the FPGA with be programmed with the evaluation project. New Nios2 applications can be created using the files from this folder.
The ip subfolder contains the HDL drivers in /hdl/src , the software drivers for HAL in /hdl/src/HAL and the AD7621 registers in /hdl/src/inc .
Hdl Contains the source files for the AD7621 HDL driver:
- The doc subfolder contains a brief documentation for the driver.
- The src subfolder contains the HDL source files.
- The tb folder contains the sources of the driver's testbench.
NiosCpu Contains the CED1Z Quartus evaluation project source files . The ip subfolder contains the AD7621 SOPC component.
Software Contains the source files of the uCProbe library and the main file of the Nios2 SBT evaluation project.
uCProbe Contains the uCProbe interface and data capture script used to acquire data from the evaluation board and store it in a local .csv file.

Install the USB-Blaster Device Driver

The USB Blaster is used to program the FPGA on the CED1Z board and also for data exchange between the system and a PC. To install the driver plug the Terasic USB Blaster into one of the PCs USB ports. Your Windows PC will find the new hardware and try to install the driver.

Since Windows cannot locate the driver for the device the automatic installation will fail and the driver has to be installed manually. In the Device Manager right click on the USB-Blaster device and select Update Driver Software.

In the next dialog box select the option Browse my computer for driver software. A new dialog will open where it is possible to point to the driver’s location. Set the location to altera\11.0\quartus\drivers\usb-blaster and press Next.

If Windows presents you with a message that the drivers have not passed Windows Logo testing, please click “Install this driver software anyway”. Upon installation completion a message will be displayed to inform that the installation is finished.


30 Nov 2011 11:18 · Adrian Costina

AD7621 Evaluation Project Overview

The evaluation project contains all the source files needed to build a system that can be used to configure the AD7621 and capture data from it. The system consists of a Nios II softcore processor that is implemented in the FPGA found on the CED1Z board and a PC application. The softcore controls the communication with the Device Under Test (DUT) and the data capture process. The captured data is saved into the SRAM of the CED1Z board and aftwerwards it is read by the PC application and saved into a comma separated values (.csv) file that can be used for further data analysis.

FPGA Design

The following components are implemented in the FPGA design:

Name Address IRQ
CPU 0x00000800 -
PLL 0x00000000 -
ONCHIP_MEM 0x00002000 -
LEDS 0x00000010 -
SYSID 0x00000020 -
SRAM 0x00400000 -
UCPROBE_UART 0x00000028 0
JTAG_UART_0 0x00000030 1
SYS_TIMER 0x00000040 2
PWR_DATA 0x00000060 -
I2C_INT 0x00000080 -
PWR_EN_CLK 0x000000a0 -
AD7621_0 0x000000c0 -
Table 1 System components

The Nios II processor contains a peripheral that implements the communication protocol with the DUT. The peripheral is divided into three logical modules: a module which implements the interface with the Avalon bus and the communication with the SRAM, a module which implements an Avalon master interface which is used to write data directly in the SRAM and a module which is the actual driver of the DUT. The driver can also be used as standalone in FPGA designs which do not contain a softcore. Following is presented a block diagram of the HDL driver and a description of the driver's interface signals.

HDL driver pinout diagram

Table 2 describes the port definitions of the Avalon peripheral:

Port Direction Width Description
Generic pins
CLK_I IN 1 Main clock input
RESET_I IN 1 System reset
Avalon Slave Interface
AVALON_WRITEDATA_I IN 32 Slave write data bus
AVALON_WRITE_I IN 1 Slave write data request
AVALON_READ_I IN 1 Slave read data request
AVALON_ADDRESS_I IN 2 Slave address bus
AVALON_READDATA_O OUT 32 Slave read data bus
Avalon Master Interface
AVALON_MASTER_WAITREQUEST IN 1 Master wait request signal
AVALON_MASTER_ADDRESS_O OUT 32 Master address bus
AVALON_MASTER_BYTEENABLE_O OUT 2 Master byte enable signals
AVALON_MASTER_WRITEDATA_O OUT 16 Master write data bus
External connectors
ADC_DB_IO I/O 16 ADC bidirectional data bus used to write/read data to/from the AD7621 eval board.
ADC_BUSY_I IN 1 Busy Input. Transitions HIGH when a conversion is started and remains HIGH until the conversion is complete and the data is latched into the on-chip shift register. The falling edge of BUSY could be used as a data-ready clock signal.
ADC_CS_N_O OUT 1 Chip Select. When CS and RD are both LOW, the Interface Parallel or Serial Output Bus is enabled. CS is also used to gate the external serial clock.
ADC_RD_N_O OUT 1 Read Data. When CS and RD are both LOW, the Interface Parallel or Serial Output Bus is enabled.
ADC_WR_N_O OUT 1 Used manually configure the AD7621 evaluation board, by writing the internal registers of the FPGA.
ADC_CONTROL_O OUT 1 Used to select between stand-alone mode or manually configure the AD7621 evaluation board
ADC_ADDR_O OUT 3 Used to manually configure the AD7621 evaluation board by writing the internal registers of the FPGA.
ADC_RESET_O OUT 1 Used to reset the evaluation board
Table 2 Port description

Table 3 describes the registers of the Avalon peripheral:

Name Offset Width Access Description
CONTROL_REGISTER 0 32 RW Bit 0 is used to start data acquisition
Bit 1 is used to initiate software reset of the core
Bit 2 is used to configure the Avalon write master core to write data to the same location
Bit 3 is used to write data to the AD7621 evaluation board
ACQ_COUNT_REGISTER 1 32 RW Register used to configure the number of samples to be acquired when acquisition is started
BASE_REGISTER 2 32 RW Register used to configure the base address of the memory location where the acquired data is to be written
STATUS 3 32 R Bit 0 is used to signal that the acquisition is complete
Bit 1 is used to signal that the internal memory buffer has been overflown
Bit 2 is used to signal that the user has performed a write of a read only register register
Bit 3 is used to signal that the user has performed a read of an reserved register
DUT_WRITE_REGISTER 4 32 W Register used to perform writes on the device under test. Bits [15:0] are used for data and [18:16] are used as address. The rest are discarded
Table 3 Register description

The follwing figure presents the timing diagram for the read operations from the AD7621 core.

Read operations time diagram

Quick Evaluation

The next sections of this document present all the steps needed to create a fully functional project that can be used for evaluating the operation of the ADI platform. It is possible to skip these steps and load into the FPGA an image that contains a fully functional system that can be used together with the uC-Probe interface for the ADI platform evalution. The first step of the quick evaluation process is to program the FPGA with the image provided in the lab files. Before the image can be loaded the Quartus II Web Edition tool or the Quartus II Programmer must be installed on your computer. To load the FPGA image you must first make sure that the USB cable is not connected to the CED1Z board. Connect the USB Blaster to the J6 connector of the CED1Z and power the board. Run the program_fpga.bat batch file located in the ADIEvalBoard/FPGA folder. Now the FPGA contains a fully functional system and it is possible to skip directly to the Evaluation Project User Interface section of this document

30 Nov 2011 11:21 · Adrian Costina

NIOS II Software Design

This section presents the steps for developing a software application that will run on the CED1Z system and will be used for controlling and monitoring the operation of the ADI evaluation board.

Create a new project using the NIOS II Software Build Tools for Eclipse

Launch the Nios II SBT from the Start → All Programs → Altera → Nios II EDS 11.0 → Nios II 11.0 Software Build Tools for Eclipse (SBT).

NOTE: Windows 7 users will need to right-click and select Run as administrator. Another method is to right-click and select Properties and click on the Compatibility tab and select the Run This Program As An Administrator checkbox, which will make this a permanent change.

1. Initialize Eclipse workspace

  • When Eclipse first launches, a dialog box appears asking what directory it should use for its workspace. It is useful to have a separate Eclipse workspace associated with each hardware project that is created in SOPC Builder. Browse to the ADIEvalBoard directory and click Make New Folder to create a folder for the software project. Name the new folder “eclipse_workspace”. After selecting the workspace directory, click OK and Eclipse will launch and the workbench will appear in the Nios II perspective.

2. Create a new software project in the SBT

  • Select File → New → Nios II Application and BSP from Template.

  • Click the Browse button in the SOPC Information File Name dialog box.
  • Select the uC.sopcinfo file located in the ADIEvalBoard/FPGA directory.
  • Set the name of the Application project to “ADIEvalBoard”.
  • Select the Blank Project template under Project template.
  • Click the Finish button.

The tool will create two new software project directories. Each Nios II application has 2 project directories in the Eclipse workspace.

  • The application software project itself - this where the application lives.
  • The second is the Board Support Package (BSP) project associated with the main application software project. This project will build the system library drivers for the specific SOPC system. This project inherits the name from the main software project and appends “_bsp” to that.

Since you chose the blank project template, there are no source files in the application project directory at this time. The BSP contains a directory of software drivers as well as a system.h header file, system initialization source code and other software infrastructure.

Configure the Board Support Package

  • Configure the board support package to specify the properties of this software system by using the BSP Editor tool. These properties include what interface should be used for stdio and stderr messages, the memory in which stack and heap should be allocated and whether an operating system or network stack should be included with this BSP.
  • Right click on the ADIEvalBoard_bsp project and select Nios II → BSP Editor… from the right-click menu.

The software project provided in this lab does not make use of an operating system. All stdout, stdin and stderr messages will be directed to the jtag_uart.

  • Select the Common settings view. In the Common settings view, change the following settings:
    • Select the jtag_uart_0 for stdin, stdout and stderr messages. Note that you have more than one choice.
    • Select none for the sys_clk_timer and timestamp_timer.

The memory used by the design is should be changed from OnChip ram to SRAM for the .text region.

  • Select Linker Script tab.
  • Change .text region Linker Region Name from onchip_mem to sram.

  • Select File → Save to save the board support package configuration to the settings.bsp file.
  • Click the Generate button to update the BSP.
  • When the generate has completed, select File → Exit to close the BSP Editor.

Configure BSP Project Build Properties

In addition to the board support package settings configured using the BSP Editor, there are other compilation settings managed by the Eclipse environment such as compiler flags and optimization level.

  • Right click on the ADIEvalBoard_bsp software project and select Properties from the right-click menu.
  • On the left-hand menu, select Nios II BSP Properties.
  • During compilation, the code may have various levels of optimization which is a tradeoff between code size and performance. Change the Optimization level setting to Level 2
  • Since our software does not make use of C++, uncheck Support C++.
  • Check the Reduced device drivers option
  • Check the Small C library option
  • Press Apply and OK to regenerate the BSP and close the Properties window.

Add source code to the project

In Windows Explorer locate the project directory which contains a directory called Software. In Windows Explorer select all the files and directories from the Software folder and drag and drop them into the Eclipse software project ADIEvalBoard.

  • Select all the files and folders and drag them over the ADIEvalBoard project in the SBT window and drop the files onto the project folder.

  • A dialog box will appear to select the desired operation. Select the option Copy files and folders and press OK.

  • This should cause the source files to be physically copied into the file system location of the software project directory and register these source files within the Eclipse workspace so that they appear in the Project Explorer file listing.

Configure Application Project Build Properties

Just as you configured the optimization level for the BSP project, you should set the optimization level for the application software project ADIEvalBoard as well.

  • Right click on the ADIEvalBoard software project and select Properties from the right-click menu.
  • On the left-hand menu, select the Nios II Application Properties tab
  • Change the Optimization level setting to Level 2.
  • Press Apply and OK to save the changes.

Define Application Include Directories

Application code can be conveniently organized in a directory structure. This section shows how to define these paths in the makefile.

  • In the Eclipse environment double click on to open the file.
  • Click the Ctrl and A keys to select all the text. Click the Ctrl and C keys to copy all the text.

  • Double click on Makefile to open the file.
  • If you see the message shown here about resources being out of sync, right click on the Makefile and select Refresh.

  • Select the line APP_INCLUDE_DIRS :=

  • Click the Ctrl and V keys to replace the selected line with the include paths.

  • Click the Ctrl and S keys to save the Makefile.

Compile, Download and Run the Software Project

1. Build the Application and BSP Projects

  • Right click the ADIEvalBoard_bsp software project and choose Build Project to build the board support package.
  • When that build completes, right click the ADIEvalBoard application software project and choose Build Project to build the Nios II application.

These 2 steps will compile and build the associated board support package, then the actual application software project itself. The result of the compilation process will be an Executable and Linked Format (.elf) file for the application, the ADIEvalBoard.elf file.

In case an error appears at compile time with a description like : section .rodata loaded at [00400164,00400477] overlaps section .text loaded at [00400164,004054d7] the enable_alt_load_copy_exceptions option must be unchecked from BSP Editor → Main → Settings → Advanced→ hal.linker

2. Verify the Board Connection

The CED1Z hardware is designed with a System ID peripheral. This peripheral is assigned a unique value based on when the hardware design was last modified in the SOPC Builder tool. SOPC Builder also places this information in the .sopcinfo hardware description file. The BSP is built based on the information in the .sopcinfo file.

  • Select the ADIEvalBoard application software project.
  • Select Run → Run Configurations…
  • Select the Nios II Hardware configuration type.
  • Press the New button to create a new configuration.
  • Change the configuration name to CED1Z and click Apply.
  • On the Target Connection tab, press the Refresh Connections button. You may need to expand the window or scroll to the right to see this button.
  • Select the jtag_uart_0 as the Byte Stream Device for stdio.
  • Check the Ignore mismatched system ID option.
  • Check the Ignore mismatched system timestamp option.

3. Run the Software Project on the Target

To run the software project on the Nios II processor:

  • Before running the the software project, the FPGA located on the CED1Z must be programmed with the Nios II system image. To program the FPGA run the ADIEvalBoard/FPGA/program_fpga.bat script.
  • Press the Run button in the Run Configurations window. This will re-build the software project to create an up–to-date executable and then download the code into memory on the CED1Z hardware. The debugger resets the Nios II processor, and it executes the downloaded code. Note that the code is verified in memory before it is executed

The code size and start address might be different than the ones displayed in the above screenshot.

30 Nov 2011 11:25 · Adrian Costina

uC-Probe Interface

A notable challenge in embedded systems development is to overcome the lack of feedback that such systems typically provide. Many developers resort to blinking LEDs or instrumenting their code with printf() in order to determine whether or not their systems are running as expected. Micrium provides a unique tool named µC-Probe to assist these developers. With this tool, developers can effortlessly read and write the variables on a running embedded system. This section presents the steps required to run the demonstration project for the ADI evaluation board. A description of the uC-Probe demonstration interface is provided.

Configure uC-Probe

Launch uC-Probe from the Start → All Programs → Micrium → uC-Probe.

Select uC-Probe options.

  • Click on the uC-Probe icon on the top left portion of the screen.
  • Click on the Options button to open the dialog box.

Set target board communication protocol as JTAG UART

  • Click on the Communication tab icon on the top left portion of the dialog box
  • Select the JTAG UART option.

Setup JTAG UART communication settings

  • Select the JTAG-UART option from the Communication tab.
  • Press the Open File button to select the JTAG Debug Information file (.jdi)
  • Navigate to the ADIEvalBoard/FPGA folder and select the ced1z.jdi file. Press Open.
  • Type the value 1 in the the Device Id window.

  • Select uCProbe_uart(0) from the Instance Id pulldown menu.

  • Press Apply and OK to exit the options menu. The embedded target has two UARTs. uC-Probe will be communicating with the uCProbe_uart.
30 Nov 2011 11:28 · Adrian Costina

Load and Run the Demonstration Project

  • Click the Open option from the uC-Probe menu and select the file ADIEvalBoard/ucProbe/AD7621_Interface.wsp.

  • Before opening the interface uC-Probe will ask for a symbols file that must be associated with the interface. If the lab was done according to the steps provided in the Quick Evaluation section, select the file ADIEvalBoard/ucProbe/ADIEvalBoard.elf to be loaded as a symbol file, otherwise select the file ADIEvalBoard/FPGA/software/ADIEvalBoard/ADIEvalBoard.elf to be loaded as a symbol file.

  • Run the demonstration project by pressing the Play button.

  • Run the ADIEvalBoard/uCProbe/data_capture.bat script. A DOS command prompt window will open. This window must be closed only when the uCProbe demonstration project will be closed.

Evaluation Project User Interface

The following figure presents the uC-Probe interface that can be used for monitoring and controlling the operation of the EVAL-AD7621EDZ evaluation board.

Demonstration Project User Interface

In order to capture data from the ADC using the uCProbe demonstration project the following steps must be performed:

  • Make sure that the CED1Z FPGA is properly programmed and the USB Blaster is connected to the CED1Z board.
  • Start uc/Probe application.
  • Depending on how the AD7621 part is configured set the data format to either Binary Offset or 2's Complement.
  • Press Acquisition button. At this point 1 Mbyte of data will be acquired from the ADC and saved into the CED1Z SRAM memory. The Acquisition In Progress LED is lit to signal that the data is acquired from the ADC. When the data acquisition is complete the Acquisition Complete LED turns green.
  • The data stored in the CED1Z SRAM memory is transfered to the PC through the JTAG-UART link provided by the USB Blaster. The Transfer In Progress LED is lit as long as the data is transferred from the CED1Z to the PC. Whe the data transfer is complete the Transfer Complete LED turns green.
  • After the data is transferred to the PC it is converted to either Binary offset or 2's Complement 16 bit values. The Processing Data In Progress LED is lit as long as the data conversion is performed. When the conversion is complete the Processing Data Complete LED turns green.
  • The data captured from the ADC is saved into a comma separated values (.csv) file named Acquisition.csv, located in the same folder as the data_capture.bat file. While the data is saved the Writing File In Progress LED is lit. When the data write process is complete the Writing in File Complete LED turns green.
  • The data capture status is also displayed in the opened command window as shown in the figure below.

Demonstration Project Command Interface

  • A new acquisition can be started by reactivating the Acquisition button.
  • After all the needed data is acquired the uCProbe program and the command window can be closed.

Note: If several consecutive data acquisitions are performed the captured data is appended to the Acquisition.csv file.


In case there is a communication problem with the board the follwing actions can be perfomed in order to try to fix the issues:

  • Check that the evaluation board is powered.
  • Make sure the USB cable is not connected to the CED1Z. In case it is, disconnect it and reset the board.
  • Check that the USB Blaster cable is properly connected to the device and to the computer and that the USB Blaster Device Driver driver is installed correctly. If the driver is not correctly installed perform the steps described in the Getting Started → Install te USB-Blaster Device Driver section.
  • In uC-Probe right-click on the System Browser window select Remove Symbols. A dialog box will open to select the symbols to remove. Press OK to remove the symbols.

  • After removing the symbols a new set of symbols must be added in order for the interface to be functional. In uC-Probe right-click on the System Browser window select Add Symbols. A dialog box will open to select the symbols to be added. If the lab was done according to the steps provided in the Quick Evaluation section, select the file ADIEvalBoard/ucProbeInterface/ADIEvalBoard.elf to be loaded as a symbol file, otherwise select the file ADIEvalBoard/FPGA/software/ADIEvalBoard/ADIEvalBoard.elf to be loaded as a symbol file.

  • If the communication problem persists even after performing the previous steps, restart the uC-Probe application and try to run the interface again.

More information

30 Nov 2011 11:30 · Adrian Costina
resources/fpga/altera/ced1z/ad7621.1341216524.txt.gz · Last modified: 02 Jul 2012 10:08 by Adrian Costina