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ADN2850 - Microcontroller No-OS Driver

Supported Devices

Evaluation Boards


The ADN2850 is a dual-channel, nonvolatile memory, digitally controlled resistors with 1024-step resolution, offering guaranteed maximum low resistor tolerance error of ±8%. The device performs the same electronic adjustment function as a mechanical rheostat with enhanced resolution, solid state reliability, and superior low temperature coefficient performance.The versatile programming of the ADN2850 via an SPI®-compatible serial interface allows 16 modes of operation and adjustment including scratchpad programming, memory storing and restoring, increment/decrement, ±6 dB/step log taper adjustment, wiper setting readback, and extra EEMEM for user-defined information such as memory data for other components, look-up table, or system identification information.

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 driver for the ADN2850 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 ADN2850 driver can be used exactly as it is provided.

There are three functions which are called by the ADN2850 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 ADN2850 driver:

Function Description
unsigned char ADN2850_Init(void) Initialize the communication with the device.
void ADN2850_SendCommand(unsigned char command,unsigned char address, unsigned short Data); Send a command to the device. It will transmit 3 bytes.
unsigned short ADN2850_Read(unsigned char readSource, unsigned char address); Read from register or from EEMEM.
void ADN2850_RepeatLastCMD(void) A subtle feature of the ADN2850 is that a subsequent CS strobe, without clockand data, repeats a previous command.
void ADN2850_WaitForRdy(void) Waits for RDY pin to go LOW.
unsigned short ADN2850_OhmConversion(unsigned long rawData) Determines the programmed output resistance between Bx and Wx terminal.


Renesas RL78G13 Quick Start Guide

This section contains a description of the steps required to run the ADN2850 demonstration project on a Renesas RL78G13 platform.

Required Hardware

Required Software

Hardware Setup

An EVAL-ADN2850SDZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:

  EVAL-ADN2850SDZ A connector Pin SYNC_BF  (CS)     → YRDKRL78G13 J11 connector Pin 1
  EVAL-ADN2850SDZ A connector Pin DIN_BF   (MOSI)   → YRDKRL78G13 J11 connector Pin 2
  EVAL-ADN2850SDZ A connector Pin SDO_BF   (MISO)   → YRDKRL78G13 J11 connector Pin 3
  EVAL-ADN2850SDZ A connector Pin SCLK_BF  (SCLK)   → YRDKRL78G13 J11 connector Pin 4
  EVAL-ADN2850SDZ A connector Pin RDY      (RDY)    → YRDKRL78G13 J11 connector Pin 7
  EVAL-ADN2850SDZ A connector Pin RESET_BF (Reset)  → YRDKRL78G13 J11 connector Pin 9
  EVAL-ADN2850SDZ A connector Pin WP_BF    (WP)     → YRDKRL78G13 J11 connector Pin 10
  EVAL-ADN2850SDZ A connector Pin MUX-A0   (MUX_A0) → YRDKRL78G13 J18 connector Pin 30  
  EVAL-ADN2850SDZ A connector Pin MUX-A1   (MUX_A1) → YRDKRL78G13 J18 connector Pin 29  
  EVAL-ADN2850SDZ A connector Pin MUX-A2   (MUX_A2) → YRDKRL78G13 J18 connector Pin 28  

Software Setup

With the Applilet3 for RL78G13 tool the following peripherals have to be configured:

CSI10 (Clocked Serial Interface 10) – For the ADN2850 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:

  • Choose for the Watchdog timer operation setting: Unused option.

Reference Project Overview

The reference project initializes the device, reads the tolerance from EEMEM, and then sets RDAC1 output resistance to the value 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 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

  • Run the Applilet3 for RL78G13 tool and create a new project for R5F100LE processor. Select IAR Compiler build tool, a project name, a location for the new project and press OK.

  • Keep the default Pin assignment setting and click Fix settings.

  • 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.

  • After all the desired peripherals are configured click on the Generate Code button and a new workspace and a new project for the IAR Embedded Workbench will be generated. After the code was generated close the Applilet3 for RL78G13 tool.

Step 2 - IAR Embedded Workbench for Renesas RL78

  • Run the IAR Embedded Workbench and open the workspace created with the Applilet3 tool.

  • Copy the files extracted from the zip file into the user_src folder, located in the project’s folder.

  • The new source files have to be included into the project. Add in the user_src group the files from the corresponding folder (Right click on the group and select Add – Add Files…). Because a new Main file was included the r_main.c file from the applilet_src group has to be deleted (Right click on the file and select Remove).

  • Now the debugger driver has to be selected from the project’s options. Right click on the project name and select Options. From the Debugger category choose the TK Debugger Driver.

  • Now, the project is ready to be compiled and downloaded on the board. Press the F7 key to compile it. Press CTRL + D to download and debug the project.

29 Feb 2012 17:01 · dragosb
resources/tools-software/uc-drivers/renesas/adn2850.1333711079.txt.gz · Last modified: 06 Apr 2012 13:17 by DragosB