Table of Contents
AD9834 - Microcontroller No-OS Driver
The AD9834 is a 75 MHz low power DDS device capable of producing high performance sine and triangular outputs. It also has an on-board comparator that allows a square wave to be produced for clock generation. Consuming only 20 mW of power at 3 V makes the AD9834 an ideal candidate for power-sensitive applications. Capability for phase modulation and frequency modulation is provided. The frequency registers are 28 bits; with a 75 MHz clock rate, resolution of 0.28 Hz can be achieved. Similarly, with a 1 MHz clock rate, the AD9834 can be tuned to 0.004 Hz resolution. Frequency and phase modulation are affected by loading registers through the serial interface and toggling the registers using software or the FSELECT pin and PSELECT pin, respectively.
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 Renesas platforms.
The driver contains two parts:
- The driver for the AD9834 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 AD9834 driver can be used exactly as it is provided. There are three functions which are called by the AD9834 driver:
- SPI_Init() – initializes the communication peripheral.
- SPI_Write() – writes data to the device.
- SPI_Read() – reads data from the device.
The implementation of these three functions depends on the used microcontroller.
The following functions are implemented in this version of AD9834 driver:
|unsigned char AD9834_Init(void))||Initializes the SPI communication peripheral and resets the part.|
|void AD9834_Reset(void)||Sets the Reset bit of the AD9834.|
|void AD9834_ClearReset(void)||Clears the Reset bit of the AD9834.|
|void AD9834_SetRegisterValue(unsigned short regValue)||Writes the value to a register.|
|void AD9834_SetFrequency(unsigned short reg, unsigned long val)||Writes to the frequency registers.|
|void AD9834_SetPhase(unsigned short reg, unsigned short val)||Writes to the phase registers.|
|void AD9834_Setup(unsigned short freq, unsigned short phase, unsigned short type, unsigned short commandType)||Selects the Frequency,Phase and Waveform type.|
Renesas RX62N Quick Start Guide
This section contains a description of the steps required to run the AD9834 demonstration project on a Renesas RX62N platform.
An EVAL-AD9834SDZ board has to be interfaced with the Renesas Demonstration Kit (RDK) for RX62N:
EVAL-AD9834SDZ test point SDATA → YRDKRX62N J8 connector Pin 19 EVAL-AD9834SDZ test point SCLK → YRDKRX62N J8 connector Pin 20 EVAL-AD9834SDZ test point FSYNC → YRDKRX62N J8 connector Pin 15 EVAL-AD9834SDZ test point FSEL1 → YRDKRX62N JN1 connector Pin 17 EVAL-AD9834SDZ J3 connector Pin AVDD → YRDKRX62N J8 connector Pin 3 EVAL-AD9834SDZ J2 connector Pin DVDD → YRDKRX62N J8 connector Pin 3 EVAL-AD9834SDZ J3 connector Pin AGND → YRDKRX62N J8 connector Pin 4 EVAL-AD9834SDZ J2 connector Pin DGND → YRDKRX62N J8 connector Pin 4
Reference Project Overview
The demo program sets up the AD9834 part to output sinusoidal and triangle waveforms. The frequency and the type of the wave are displayed on the LCD.
Software Project Setup
This section presents the steps for developing a software application that will run on the Renesas Demo Kit for RX62N for controlling and monitoring the operation of the ADI part.
- Run the High-performance Embedded Workshop integrated development environment.
- A window will appear asking to create or open project workspace. Choose “Create a new project workspace” option and press OK.
- From “Project Types” option select “Application”, name the Workspace and the Project “ADIEvalBoard”, select the “RX” CPU family and “Renesas RX Standard” tool chain. Press OK.
- A few windows will appear asking to configure the project:
- In the “Select Target CPU” window, select “RX600” CPU series, “RX62N” CPU Type and press Next.
- In the “Option Setting” windows keep default settings and press Next.
- In the “Setting the Content of Files to be generated” window select “None” for the “Generate main() Function” option and press Next.
- In the “Setting the Standard Library” window press “Disable all” and then Next.
- In the “Setting the Stack Area” window check the “Use User Stack” option and press Next.
- In the “Setting the Vector” window keep default settings and press Next.
- In the “Setting the Target System for Debugging” window choose “RX600 Segger J-Link” target and press Next.
- In the “Setting the Debugger Options” and “Changing the Files Name to be created” windows keep default settings, press Next and Finish.
- The workspace is created.
- The RPDL (Renesas Peripheral Driver Library) has to integrated in the project. Unzip the RPDL files (double-click on the file “RPDL_RX62N.exe”). Navigate to where the RPDL files were unpacked and double-click on the “Copy_RPDL_RX62N.bat” to start the copy process. Choose the LQFP package, type the full path where the project was created and after the files were copied, press any key to close the window.
- The new source files have to be included in the project. Use the key sequence Alt, P, A to open the “Add files to project ‘ADIEvalBoard’” window. Double click on the RPDL folder. From the “Files of type” drop-down list, select “C source file (*.C)”. Select all of the files and press Add.
- To avoid conflicts with standard project files remove the files “intprg.c” and “vecttbl.c” which are included in the project. Use the key sequence Alt, P, R to open the “Remove Project Files” window. Select the files, click on Remove and press OK.
- Next the new directory has to be included in the project. Use the key sequence Alt, B, R to open the “RX Standard Toolchain” window. Select the C/C++ tab, select “Show entries for: Include file directories” and press Add. Select “Relative to: Project directory”, type “RPDL” as sub-directory and press OK.
- The library file path has to be added in the project. Select the Link/Library tab, select “Show entries for: Library files” and press Add. Select “Relative to: Project directory”, type “RPDL\RX62N_library” as file path and press OK.
- Because the “intprg.c” file was removed the “PIntPrg” specified in option “start” has to be removed. Change “Category” to “Section”. Press “Edit”, select “PIntPRG” and press “Remove”. From this window the address of each section can be also modified. After all the changes are made press OK two times.
- At this point the files extracted from the zip file located in the “Software Tools” section have to be added into the project. Copy all the files from the archive into the project folder.
- Now, the files have to be included in the project. Use the key sequence Alt, P, A to open the “Add files to project ‘ADIEvalBoard’” window. Navigate into ADI folder. From the “Files of type” drop-down list, select “Project Files”. Select all the copied files and press Add.
- Now, the project is ready to be built. Press F7. The message after the Build Process is finished has to be “0 Errors, 0 Warnings”. To run the program on the board, you have to download the firmware into the microprocessor’s memory.