AD5421-微控制器无操作系统驱动程序

消耗积分:3 | 格式:pdf | 大小:1.38MB | 2021-05-22

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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.

AD5421 - Microcontroller No-OS Driver

Supported Devices

AD5421

Evaluation Boards

EVAL-AD5421SDZ

Overview

The AD5421 is a complete, loop-powered, 4 mA to 20 mA digital-to-analog converter (DAC) designed to meet the needs of smart transmitter manufacturers in the industrial control industry. The DAC provides a high precision, fully integrated, low cost solution in a compact TSSOP package and LFCSP packages.

The AD5421 includes a regulated voltage output that is used to power itself and other devices in the transmitter. This regulator provides a regulated 1.8 V to 12 V output voltage. The AD5421 also contains 1.22 V and 2.5 V references, thus eliminating the need for a discrete regulator and voltage reference.

The AD5421 can be used with standard HART® FSK protocol communication circuitry without any degradation in specified performance. The high speed serial interface is capable of opera-ting at 30 MHz and allows for simple connection to commonly used microprocessors and microcontrollers via a SPI-compatible, 3-wire interface.

The AD5421 is guaranteed monotonic to 16 bits. It provides 0.0015% integral nonlinearity, 0.0012% offset error, and 0.0006% gain error under typical conditions.

The AD5421 is available in a 28-lead TSSOP and a 32-lead LFCSP specified over the extended industrial temperature range of −40°C to +105°C.

Applications

Industrial Process Control
4mA to 20mA loop-powered transmitters
Smart transmitters
HART network connectivity

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 AD5421 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 AD5421 driver can be used exactly as it is provided. There are three functions which are called by the AD5421 driver:

SPI_Init() – initializes the communication peripheral.
SPI_Write() – writes data to the device.
SPI_Read() – reads data from the device.

Driver architecture

The implementation of these three functions depends on the used microcontroller.

The following functions are implemented in this version of AD5421 driver:

Function	Description
unsigned char AD5421_Init(void)	Initializes the SPI communication peripheral and resets the part.
void AD5421_SetRegisterValue(unsigned char regAddress, unsigned short regValue)	Writes the value to the register.
nsigned long AD5421_GetRegisterValue(unsigned char regAddress)	Reads the value of the selected register.
void AD5421_WriteDac(unsigned short value)	Writes to the DAC register.
unsigned char AD5421_GetTemperature(void)	Read the temperature of the die.

Downloads

Renesas RL78G13 Quick Start Guide

This section contains a description of the steps required to run the AD5421 demonstration project on a Renesas RL78G13 platform.

Required Hardware

Required Software

Hardware Setup

An EVAL-AD5421SDZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:

  EVAL-AD5421SDZ test point CS    → YRDKRL78G13 J11 connector Pin 1
  EVAL-AD5421SDZ test point SDIN  → YRDKRL78G13 J11 connector Pin 2
  EVAL-AD5421SDZ test point SDOUT → YRDKRL78G13 J11 connector Pin 3
  EVAL-AD5421SDZ test point SCLK  → YRDKRL78G13 J11 connector Pin 4

Software Setup

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

CSI10 (Clocked Serial Interface 10) – For the ADI 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 demo program writes a value to the DAC register, reads the die temperature and displays it on the screen.

Software Project Tutorial

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