AD5252-微控制器无操作系统驱动程序

消耗积分:2 | 格式:pdf | 大小:1.51MB | 2021-05-13

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This version (25 Jan 2021 05:41) was approved by Robin Getz.The Previously approved version (25 Jan 2021 05:23) is available.

AD5252 - Microcontroller No-OS Driver

Supported Devices

AD5252

Evaluation Boards

EVAL-AD5252SDZ

Overview

The AD5252 is a dual channel, digitally controlled variable resistor (VR) with resolutions of 256 positions. This device performs the same electronic adjustment function as a potentiometer or variable resistor. The AD5252’s versatile programming via a Micro Controller allows multiple modes of operation and adjustment. In the direct program mode a predetermined setting of the RDAC register can be loaded directly from the micro controller. Another key mode of operation allows the RDAC register to be refreshed with the setting previously stored in the EEMEM register. When changes are made to the RDAC register to establish a new wiper position, the value of the setting can be saved into the EEMEM by executing an EEMEM save operation. Once the settings are saved in the EEMEM register, these values will be transferred automatically to the RDAC register to set the wiper position at system power ON. Such operation is enabled by the internal preset strobe and the preset can also be accessed externally. The basic mode of adjustment is the increment and decrement from the present setting of the Wiper position setting (RDAC) register. An internal scratch pad RDAC register can be moved UP or DOWN, one step of the nominal resistance between terminals A-and-B. This linearly changes the wiper-to-B terminal resistance (RWB) by one out of 64/256 positions of the AD5251/AD5252 end- to-end resistance (RAB). For non-linear changes in wiper setting, a left/right shift command adjusts levels in 6dB steps, which can be useful for sound and light alarm applications.

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):

Renesas Demo Kit for RL78G13 (Renesas)

Driver Description

The driver contains two parts:

The driver for the AD5252 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 AD5252 driver can be used exactly as it is provided.

There are three functions which are called by the AD5252 driver:

I2C_Init() – initializes the communication peripheral.
I2C_Write() – writes data to the device.
I2C_Read() – reads data from the device.

I2C driver architecture

The following functions are implemented in this version of AD5252 driver:

Function	Description
unsigned char AD5252_Init(void)	Initializes the communication with the device.
void AD5252_SendCommand(unsigned char instruction, unsigned char rDacAddress)	Sends a command to the device.
void AD5252_WaitForDevice(void)	Performs an Acknowledge Polling.
void AD5252_WriteRDAC(unsigned char rDacAddress, unsigned char data)	Writes data to a RDAC.
unsigned char AD5252_ReadRDAC(unsigned char rDacAddress)	Reads data from a RDAC.
void AD5252_WriteEEMEM(unsigned char memAddress, unsigned char data)	Writes data to EEMEM registers.
unsigned char AD5252_ReadEEMEM(unsigned char memAddress)	Reads data form EEMEM registers.

Downloads

Renesas RL78G13 Quick Start Guide

This section contains a description of the steps required to run the AD5252 demonstration project on a Renesas RL78G13 platform.

Required Hardware

Required Software

Hardware Setup

An EVAL-AD5252SDZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:

  EVAL-AD5252SDZ A connector Pin SCL_BF  (SCL)    → YRDKRL78G13 J9  connector Pin 1
  EVAL-AD5252SDZ A connector Pin SDA_BF  (SDA)    → YRDKRL78G13 J9  connector Pin 3
  EVAL-AD5252SDZ A connector Pin WP_BF   (WP)     → YRDKRL78G13 J11 connector Pin 9

Software Setup

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

IICA0 (Inter Integrated Circuit Bus) - For the AD5252 part

Choose the Single master transfer mode and configure the interface with the following settings:

Clock mode setting: fCLK/2
Local address setting – Address: 16
Operation mode setting : Standard
Operation mode setting – Transfer clock (fSCL): 100000 (bps)
Interrupt setting – Communication end interrupt priority (INTIICA0): Low
Callback function setting: Check Master transmission end and Master reception end callback functions
Callback function enhanced feature setting: Check the Callback function enhanced feature setting.

CSI10 (Clocked Serial Interface 10) – For 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.

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 RDAC1 tolerance and then continuously increases the output resistance until reaches the upper limit followed by a continuously decrease until reaches lower limit. The project also provides an example of writing and reading from EEMEM.

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 · Dragos Bogdan