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AD7920 - Microcontroller No-OS Driver
Supported Devices
Evaluation Boards
Overview
The AD7910/AD7920 are 10-bit and 12-bit, high speed, low power, successive-approximation ADCs respectively. The parts operate from a single 2.35 V to 5.25 V power supply and feature throughput rates up to 250 kSPS. The parts contain a low-noise, wide bandwidth track/hold amplifier, which can handle input frequencies in excess of 6 MHz.
The AD7910/AD7920 use advanced design techniques to achieve very low power dissipation at high throughput rates.
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.
HW Platform(s):
Driver Description
The driver contains two parts:
The Communication Driver has a standard interface, so the AD7920 driver can be used exactly as it is provided.
There are three functions which are called by the AD7920 driver:
SPI_Init() – initializes the communication peripheral.
SPI_Write() – writes data to the device.
SPI_Read() – reads data from the device.
The following functions are implemented in this version of AD7920 driver:
Function | Description |
unsigned char AD7920_Init(void) | Initializes the SPI communication peripheral. |
unsigned short AD7920_GetRegisterValue(void) | Reads data from AD7920. |
Downloads
Renesas RL78G13 Quick Start Guide
This section contains a description of the steps required to run the AD7920 demonstration project on a Renesas RL78G13 platform.
Required Hardware
Required Software
Hardware Setup
An EVAL-CN0241-SDPZ board has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:
EVAL-CN0241-SDPZ J2 connector Pin CS → YRDKRL78G13 J11 connector Pin 1
EVAL-CN0241-SDPZ J2 connector Pin DOUT → YRDKRL78G13 J11 connector Pin 3
EVAL-CN0241-SDPZ J2 connector Pin SCLK → YRDKRL78G13 J11 connector Pin 4
EVAL-CN0241-SDPZ J2 connector Pin AGND → YRDKRL78G13 J11 connector Pin 5
Software Setup
With the Applilet3 for RL78G13 tool the following peripherals have to be configured:
CSI10 (Clocked Serial Interface 10) – For the AD7920 part and the ST7579 LCD
Choose to generate the Transmit/receive function for the CSI10 and configure the interface with the following settings:
Transfer mode setting: Single transfer mode
Data length setting : 8 bits
Transfer direction setting:
MSB
Specification of data timing: Type 1
Transfer rate setting – Clock mode: Internal clock (master)
Transfer rate setting – Baudrate: 1000000 (bps)
Interrupt setting – Transfer interrupt priority (INTCSI10): Low
Uncheck the callback functions.
TM00 (Timer 00) – For the DelayMs() function
Configure TM00 as an interval timer:
Interval timer setting - Interval value(16 bits):
1 ms
Interval timer setting - Uncheck Generates INTM00 when counting is started
Interrupt setting - Uncheck End of timer channel 0 count, generate an interrupt (INTM00)
Watchdog Timer
Disable the watchdog timer:
Reference Project Overview
The reference project reads data from the AD7920 part and displays it 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 RL78G13 for controlling and monitoring the operation of the ADI part.
Two software applications have to be used: Applilet3 for RL78G13 (a tool that automatically generates device drivers for MCU peripheral functions) and IAR Embedded Workbench for Renesas RL78 (the integrated development environment).
Step 1 - Applilet3 for RL78G13
Now the desired peripherals can be configured and the code can be generated. For example, if the clocked serial interface 10 (CSI10) has to be configured, select the Serial peripheral, choose for the Channel 2 of Serial Array Unit 0 (SAU0) the CSI10 interface, Transmit/receive function option and then go to CSI10 tab.
To configure the
CSI10 interface for serial transmissions of 8 bits, with
MSB first, with the data captured on clock's rising edge, with a frequency of the clock of 1
MHz and the idle state high, the settings from the following image have to be made.
Step 2 - IAR Embedded Workbench for Renesas RL78
Renesas RX62N Quick Start Guide
This section contains a description of the steps required to run the AD7920 demonstration project on a Renesas RX62N platform.
Required Hardware
Required Software
Hardware Setup
An EVAL-CN0241-SDPZ board has to be interfaced with the Renesas Demonstration Kit (RDK) for RX62N:
EVAL-CN0241-SDPZ J2 connector Pin CS → YRDKRX62N J8 connector Pin 15
EVAL-CN0241-SDPZ J2 connector Pin DOUT → YRDKRX62N J8 connector Pin 22
EVAL-CN0241-SDPZ J2 connector Pin SCLK → YRDKRX62N J8 connector Pin 20
EVAL-CN0241-SDPZ J2 connector Pin AGND → YRDKRX62N J8 connector Pin 4
Reference Project Overview
The reference project reads data from the AD7920 part and displays it 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.
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.
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.