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This version (08 Apr 2021 16:46) was approved by Darius B.The Previously approved version (08 Apr 2021 16:41) is available.Diff

AD7746 - Microcontroller No-OS Driver

Supported Devices

Evaluation Boards

Overview

The AD7745/AD7746 are a high resolution, Σ-Δ capacitance-to-digital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture fea-tures inherent high resolution (24-bit no missing codes, up to 21-bit effective resolution), high linearity (±0.01%), and high accuracy (±4 fF factory calibrated). The AD7745/AD7746 capacitance input range is ±4 pF (changing), while it can accept up to 17 pF common-mode capacitance (not changing), which can be balanced by a programmable on-chip, digital-to-capacitance converter (CAPDAC).

The AD7745 has one capacitance input channel, while the AD7746 has two channels. Each channel can be configured as single-ended or differential. The AD7745/AD7746 are designed for floating capacitive sensors. For capacitive sensors with one plate connected to ground, the AD7747 is recommended.

The parts have an on-chip temperature sensor with a resolution of 0.1°C and accuracy of ±2°C. The on-chip voltage reference and the on-chip clock generator eliminate the need for any external components in capacitive sensor applications. The parts have a standard voltage input, which together with the differential reference input allows easy interface to an external temperature sensor, such as an RTD, thermistor, or diode.

The AD7745/AD7746 have a 2-wire, I2C-compatible serial interface. Both parts can operate with a single power supply from 2.7 V to 5.25 V. They are specified over the automotive temperature range of –40°C to +125°C and are housed in a 16-lead TSSOP package.

Applications

Automotive, Industrial and Medical Systems for:

  • Pressure Measurement
  • Position Sensors
  • Level Sensors
  • Flowmeters
  • Humidity Sensors
  • Impurity Detection

Hardware setup

The board has a USB port that is by default used to power the board. To power the converter chip, depending on your controller logic level, you need to install a jumper in either the 3.3V or 5V positions of AVDD select header LK1.

3.3V AVDD:

5V AVDD:

Once you've verified that the chip is powered correctly by measuring the AVDD-GND test points, you may proceed to connecting the SDA and SCL lines to your controller. Male pin headers are available at LK2.8 and LK2.6 respectively.

Building the project

Go to the no-OS/projects/ad7746-ebz directory and follow the build instructions below.

No-OS Build Guide

NOTE: This build guide is valid for the projects found in the no-OS/projects folder. If your project resides elsewhere under the no-OS repository tree, it is a legacy project. A build guide for legacy projects can be found Build no-OS with GNU make.

Clone NO-OS with the --recursive flag:

git clone --recursive https://github.com/analogdevicesinc/no-OS

If however you've already cloned NO-OS without the --recursive flag, you may initialize all the submodules in an existing NO-OS clone with:

git submodule update --recursive --init

Build Prerequisites

Prior to building a no-OS project, it is required to set up some environment variables so that the build process may find the necessary tools (compiler, linker, SDK etc.).

Use the following commands to prepare your environment for building no-OS projects:

Linux (Click to expand)

Linux (Click to expand)

Make sure the GNU Make version you are using is >= 4.2.

Intel (Click to expand)

Intel (Click to expand)

Assuming the SDK is installed at this path:

/path/to/intel
└── intelFPGA
    └── 18.1

Run:

$ source no-OS/tools/scripts/platform/intel/environment.sh /path/to/intel/intelFPGA 18.1

Xilinx (Click to expand)

Xilinx (Click to expand)

Assuming the Vitis 2022.2 is installed at this path:

/path/to/xilinx
├── DocNav
├── Downloads
└── Vitis
    └── 2022.2

Run:

$ source /path/to/xilinx/Vitis/2022.2/settings64.sh

STM32 (Click to expand)

STM32 (Click to expand)

  • Install stm32cubeide to default location /opt/stm32cubeide. If you'd rather install it at a different location, run export STM32CUBEIDE=/path/to/your/stm32cubeide in the terminal used for building.
  • Install stm32cubemx to default location /opt/stm32cubemx. If you'd rather install it at a different location, run export STM32CUBEMX=/path/to/your/stm32cubemx in the terminal used for building.
  • Currently we are testing projects with CubeMx Version 6.5.0, but other versions should work as well.
  • Install java (openjdk-17), sed and head (if not already present, they normally are).
  • Install python (if not already present) and make sure python command executes Python3 (not Python2). This can be easily achieved by running the following command sudo apt install python-is-python3.

Maxim (Click to expand)

Maxim (Click to expand)

  • Install the Maxim Micros SDK.
  • Set the MAXIM_LIBRARIES environment variable to the MaximSDK/Libraries path (the default should be ~/MaximSDK/Libraries).
  • For visual debugging and building, install Visual Studio Code, and the Cortex-Debug extension.

Mbed (Click to expand)

Mbed (Click to expand)

  • Install Mbed CLI 1 as per guide here: https://os.mbed.com/docs/mbed-os/v6.15/build-tools/install-and-set-up.html .Usually the following steps should be sufficient: sudo apt install python3 python3-pip git mercurial gcc-arm-none-eabi and sudo python3 -m pip install mbed-cli pyelftools==0.29.
  • Configure the compiler location with Mbed CLI. This can be carried out by running the “mbed config -G GCC_ARM_PATH “path-to-your-gcc-compiler”” in Command Prompt.

Pico (Click to expand)

Pico (Click to expand)

  • Set the PICO_SDK_PATH environment variable to the pico-sdk cloned repository path.
  • Install the J-Link software
  • Set the JLINK_SERVER_PATH environment variable to the JLinkGDBServerCLExe path (the default path should be /opt/SEGGER/JLink/JLinkGDBServerCLExe).
  • For visual debugging and building, install Visual Studio Code, and the Cortex-Debug extension.

ADuCM3029 (Click to expand)

ADuCM3029 (Click to expand)

Please install all the necessary packs locally and then manually import them in CrossCore

Common Issues with environment setup:

  • Makefiles searches for the CCES_HOME in its default installation directory. It may happen that multiple version are installed and may not work. To select a CCES_HOME run export CCES_HOME=/opt/analog/cces/2.10.0

Windows (Click to expand)

Windows (Click to expand)

Open up a Git Bash as Administrator once and run the tools/scripts/git-bash.sh script. Close the window. You only need to do this once per Git Bash installation.
Use Git Bash (unelevated) for the rest of your development.

Xilinx (Click to expand)

Xilinx (Click to expand)

Assuming the Vitis 2022.2 is installed at this path:

C:\Xilinx
├── DocNav
├── Downloads
└── Vitis
    └── 2022.2

Run:

$ export PATH=/c/Xilinx/Vitis/2022.2/bin:/c/Xilinx/Vitis/2022.2/gnu/aarch64/nt/aarch64-none/bin/:$PATH

Maxim (Click to expand)

Maxim (Click to expand)

  • Install the Maxim Micros SDK to a path without whitespaces like C:\MaximSDK.
  • Set the MAXIM_LIBRARIES environment variable by running: export MAXIM_LIBRARIES=/c/MaximSDK/Libraries.
  • (Optional) For visual debugging and building, install Visual Studio Code, and the Cortex-Debug extension.

ADuCM3029 (Click to expand)

ADuCM3029 (Click to expand)

Building a project

Go in the project directory that should be built.

Linux (Click to expand)

Linux (Click to expand)

$ cd no-OS/projects/project_name/
$ tree
.
├── builds.json
├── Makefile
├── src
└── src.mk

Intel (Click to expand)

Intel (Click to expand)

Copy the .sof and .sopcinfo to the project folder.

$ ls
Makefile  profiles  src  src.mk  system_bd.sopcinfo  adrv9009_a10gx.sof	
$ make

# Alternatively you may select a .sopcinfo file explicitly by:
$ make HARDWARE=path/to/system_bd.sopcinfo

Xilinx (Click to expand)

Xilinx (Click to expand)

Copy the .xsa in the project folder.

$ ls
Makefile  profiles  src  src.mk system_top.xsa
$ make

# Alternatively you may select an .xsa file explicitly by:
$ make HARDWARE=path/to/file.xsa

Maxim (Click to expand)

Maxim (Click to expand)

To build a project, type:

make PLATFORM=maxim TARGET=...

The TARGET specifies the chip for which the project is built. If it is missing, max32660 will be used. At the moment, the available targets are: max32650, max32655, max32660, max32665, max32670, max32690 and max78000.

Mbed (Click to expand)

Mbed (Click to expand)

To build a project, type:

make PLATFORM=mbed

Pico (Click to expand)

Pico (Click to expand)

To build a project, type:

make PLATFORM=pico

STM32 (Click to expand)

STM32 (Click to expand)

Make sure you have the .ioc file in the project directory, then type:

$ make PLATFORM=stm32

If during the project generation you get a dialog saying that you are using an .ioc file generated with an old CubeMX version, click Continue. Migrate is also a valid option but only if you know what you are doing.

If you're trying to use an .ioc file generated with a newer CubeMX than the one installed on your machine, you will get a prompt that asks you to upgrade your installation to the new version, there is no other choice than to click OK and then manually upgrade.

ADuCM3029 (Click to expand)

ADuCM3029 (Click to expand)

The ADuCM3029 projects also contain a pinmux_config.c file which contains pin configuration instructions.

# build an ADuCM3029-only project
$ make

# if the platform autodetection picks the wrong platform, explicitly specify the PLATFORM
$ make PLATFORM=aducm3029

Windows (Click to expand)

Windows (Click to expand)

Use Git Bash to run these commands.
$ cd no-OS/projects/project_name

It should contain make-related files and source files:

./no-OS/projects/project_name
├── builds.json
├── Makefile
├── src
└── src.mk

Xilinx (Click to expand)

Xilinx (Click to expand)

Copy the .xsa to the project folder and run:

./no-OS/projects/adrv9009
├── Makefile
├── profiles
├── src
├── src.mk
└── system_top.xsa

$ make

Maxim (Click to expand)

Maxim (Click to expand)

To build a project, type:

$ make PLATFORM=maxim TARGET=...

The TARGET specifies the chip for which the project is built. If it is missing, max32660 will be used. At the moment, the available targets are: max32650, max32655, max32660, max32665, max32670, max32690 and max78000.

ADuCM3029 (Click to expand)

ADuCM3029 (Click to expand)

$ export PLATFORM=aducm3029
$ make

The build process creates a build directory in the project folder:

build
├── app
├── bsp
├── obj
├── project_name.elf
└── tmp

Running/Debugging

Once the .elf, .hex or .bin file has been generated, make sure the board is powered on, JTAG cable connected and use the following commands to upload the program to the board or debug.

Uploading the binary to target is generically achieved with:

$ make run

Xilinx (Click to expand)

Xilinx (Click to expand)

For Xilinx project you can flash the board connected to a remote host. On the remote host make sure to start `hw_server`. On your development environment run

$ export XSCT_REMOTE_HOST=<remote host ip>
$ export XSCT_REMOTE_PORT=<remote host hw_server port>
$ make run

By default the `hw_server` port should be 3121.

Use the following command to launch the SDK associated to the used platform in order to be able to debug graphically by clicking the debug button:

$ make sdkopen

Fore more details about the available make rules, check out this page.

Running/Debugging in WSL

17 Mar 2021 10:27 · Darius B

Capacitive length sensor demo

The demo application uses the stdout/stin over UART for user interaction. Thus you need to set up a serial terminal with the UART_BAUDRATE specified in the src/app/parameters.h file.

Connect the serial terminal, run make run from the project folder and you should see the following demo application that you can interact with by hitting ENTER on the keyboard and by following the instructions:

[INIT] AD7746 initialization ok.
[CALIB] 1. Remove the ruler and press ENTER. 
[CALIB] 2. Place ruler to 51mm (2inch) and press ENTER.
[DEMO] Move the ruler around, its position will is read and displayed every 2 seconds.
Position: 51 mm, Temperature: 23 *C
Position: 50 mm, Temperature: 23 *C
Position: 67 mm, Temperature: 23 *C
Position: 67 mm, Temperature: 23 *C
Position: 67 mm, Temperature: 23 *C
Position: 67 mm, Temperature: 23 *C
Position: 67 mm, Temperature: 23 *C
Position: 47 mm, Temperature: 23 *C
Position: 37 mm, Temperature: 23 *C
Position: 34 mm, Temperature: 23 *C
Position: 34 mm, Temperature: 23 *C
Position: 27 mm, Temperature: 23 *C
Position: 27 mm, Temperature: 23 *C

Legacy driver

A legacy version of this driver and instructions for a Renesas microcontroller may be found at this link.

resources/tools-software/uc-drivers/ad7746.txt · Last modified: 08 Apr 2021 16:46 by Darius B