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AD7190 - Microcontroller No-OS Driver

Supported Devices

AD7190

Evaluation Boards

EVAL-AD7190EBZ

Overview

The AD7190 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). The device can be configured to have two differential inputs or four pseudo differential inputs. The on-chip channel sequencer allows several channels to be enabled, and the AD7190 sequentially converts on each enabled channel. This simplifies communication with the part. The device has two digital filter options. The choice of filter affects the rms noise/noise-free resolution at the programmed output data rate, the settling time, and the 50 Hz/60 Hz rejection. For applications that require all conversions to be settled, the AD7190 includes a zero latency feature.

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 AD7190 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 AD7190 driver can be used exactly as it is provided.

There are three functions which are called by the AD7190 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 AD7190 driver:

Function	Description
void AD7190_SetRegisterValue(unsigned char registerAddress, unsigned long registerValue, unsigned char bytesNumber, unsigned char modifyCS)	Writes data into a register.
unsigned long AD7190_GetRegisterValue(unsigned char registerAddress, unsigned char bytesNumber, unsigned char modifyCS)	Reads the value of a register.
unsigned char AD7190_Init(void)	Initializes the SPI peripheral and checks if the AD7190 part is present.
void AD7190_Reset(void)	Resets the device.
void AD7190_SetPower(unsigned char pwrMode)	Set device to idle or power-down.
void AD7190_WaitRdyGoLow(void)	Waits for RDY pin to go low.
void AD7190_ChannelSelect(unsigned short channel)	Selects the channel to be enabled.
void AD7190_Calibrate(unsigned char mode, unsigned char channel)	Performs the given calibration to the specified channel.
void AD7190_RangeSetup(unsigned char polarity, unsigned char range)	Selects the polarity of the conversion and the ADC input range.
unsigned long AD7190_SingleConversion(void)	Returns the result of a single conversion.
unsigned long AD7190_ContinuousReadAvg(unsigned char sampleNumber)	Returns the average of several conversion results.
unsigned long AD7190_TemperatureRead(void)	Read data from temperature sensor and converts it to Celsius degrees.

Downloads

Renesas RL78G13 Quick Start Guide

This section contains a description of the steps required to run the AD7190 demonstration project on a Renesas RL78G13 platform.

Required Hardware

Required Software

Hardware Setup

An EVAL-AD7190EBZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:

  EVAL-AD7190EBZ J2 connector Pin CS      →  YRDKRL78G13 J11 connector Pin 1
  EVAL-AD7190EBZ J2 connector Pin DIN     →  YRDKRL78G13 J11 connector Pin 2
  EVAL-AD7190EBZ J2 connector Pin DOUT    →  YRDKRL78G13 J11 connector Pin 3
  EVAL-AD7190EBZ J2 connector Pin SCLK    →  YRDKRL78G13 J11 connector Pin 4
  EVAL-AD7190EBZ 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 AD7190 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:

checks if the AD7190 part is present;
configures the AD7190 part;
reads data from single conversion;
reads data from multiple conversions, calculates the average value and displays it;
reads data from the temperature sensor and displays it in degrees Celsius.

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

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