The ADXL355 is a low noise density, low 0g offset drift, low power, 3-axis MEMS accelerometer with selectable measurement ranges. The ADXL355 supports the ±2g, ±4g, and ±8g ranges, and offers industry leading noise, offset drift over temperature, and long term stability, enabling precision applications with minimal calibration and with very low power consumption. Applications include:
The ADXL355 accelerometers offer guaranteed temperature stability with null offset coefficients of 0.15mg/°C (max). The stability minimizes resource and expense associated with calibration and testing effort, helping to achieve higher throughput for device OEMs. In addition, the hermetic package helps ensure that the end product conforms to its repeatability and stability specifications long after they leave the factory.
With output of ±2g to ±8g full scale range (FSR), selectable digital filtering from 1 Hz to 1 kHz, and low noise density of 25µ/√Hz at less than 200µA current consumption, ADXL355 MEMS accelerometer offers performance level comparable to much more expensive devices with less power consumption and BOM cost. For general board details and to buy a board, please visit the EVAL-ADXL355-PMDZ product page.
The PMOD board is small in size with dimensions approximately 2.5 cm in width by 2.5 cm in length.
The PMOD interface is a series of standardized digital interfaces for various digital communication protocols such as SPI, I2C, and UART. These interface types were standardized by Digilent, which is now a division of National Instruments. Complete details on the PMOD specification can be found here.
The specific interface used for the EVAL-ADXL355-PMDZ boards is the extended SPI. In general ADI has adopted the extended SPI connector for all PMOD devices which have an SPI interface. It provides flexibility to add interrupts, general purpose I/O, resets, and other important digitally controlled functions.
P1 Pin Number | Pin Function | Mnemonic | P1 Pin Number | Pin Function | Mnemonic |
---|---|---|---|---|---|
Pin 1 | Chip Select | CS | Pin 7 | Interrupt 1 | INT1 |
Pin 2 | Master Out Slave In | MOSI | Pin 8 | Not Connected | NC |
Pin 3 | Master In Slave Out | MISO | Pin 9 | Interrupt 2 | INT2 |
Pin 4 | Serial Clock | SCLK | Pin 10 | Data Ready | DRDY |
Pin 5 | Digital Ground | DGND | Pin 11 | Digital Ground | DGND |
Pin 6 | Digital Power | VDD | Pin 12 | Digital Power | VDD |
The EVAL-ADXL355-PMDZ has two interrupt pins and a data ready pin which can be used as external indicators for the user. The interrupt pins can be programmed through software to reflect various status flags within the ADXL355, and those pins are accessible through the SPI PMOD header. For complete details on the individual status flags, what they mean, and how to program the chip to reflect those interrupts, please consult the ADXL355 data sheet.
When using the ADXL355 PMOD board, the 3.3V power for the PMOD comes directly from the host board it is connected to. The power from the host is generally capable of providing up to 100 mA at 3.3V; but for complete PMOD power specifications, please clickhere.
There are two device driver solutions that are provided for controlling the EVAL-ADXL355-PMDZ:
The EVAL-ADXL355-PMDZ can be used with ADICUP3029.
The following is the list of items needed in order to replicate this demo.
There are two basic ways to program the ADICUP3029 with the software for the ADXL355.
The software for the ADICUP3029_ADXL355 demo can be found here:
Prebuilt ADXL355 Hex File
Complete ADXL355 Source Files
1. Connect EVAL-ADXL355-PMDZ board at connector P9 of the EVAL-ADICUP3029.
2. Connect a micro-USB cable to the P10 connector of the EVAL-ADICUP3029 and connect it to a computer. The final setup should look similar to the picture below.
Figure 5. Hardware Setup
3. Make sure the following switches are as shown from the table below.
Figure 6. Switch Confuguration
4. From your PC, open My Computer and look for the DAPLINK drive, if you see this then the drivers are complete and correct.
Figure 7. DAPLINK Drive
3. Simply extract the provided zip file. Once extracted, you will see the pre-built hex file for the ADXL355 demo. Then drag and drop this Hex file to the DAPLINK drive and your ADICUP3029 board will be programmed. The DS2 (red) LED will blink rapidly.
4. The DS2 will stop blinking and will stay ON once the programming is done.
5. For demo purposes, place the board horizontally such that the Z-axis reading will be approximately 9.8 m/s^2.
The EVAL-ADXL355-PMDZ can be used with the MAX32655FTHR or MAX32650FTHR.
The following is the list of items needed in order to replicate this demo.
1. Connect MAX32655FTHR with the FTHR-PMOD-INTZ. Note that MAXIM feather board should have stacking headers for feather board where the interposer board will be connected.
2. Connect EVAL-ADXL355-PMDZ to the FTHR-PMOD-INTZ .
3. Power up the MAX32655FTHR by connecting it to your laptop using micro-USB
4. Open the file explorer. Drag-and-drop the pre-built hex file to the DAPLINK. If the transfer was not completed, update the firmware for the DAPLINK. Follow the steps here: https://github.com/MaximIntegrated/max32625pico-firmware-images/
5. Open PuTTY or other similar software. Check the Device Manager to set correct COM for the MAX32655FTHR. Set baud rate according to hex file used:
Hex file | Baud rate |
---|---|
eval-adxl355-pmdz_maxim_dummy_example_max32655_adxl355 | 57600 |
eval-adxl355-pmdz_maxim_iio_example_max32655_adxl355 | 115200 |
eval-adxl355-pmdz_maxim_iio_trigger_example_max32655_adxl355.hex | 115200 |
1. Using a 10-pin ribbon cable, connect the MAX32625PICO to the MAX32650FTHR.
2. Connect MAX32650FTHR to the FTHR-PMOD-INTZ.
3. Connect EVAL-ADXL355-PMDZ to the FTHR-PMOD-INTZ .
MAX31855PMB1 | FTHR-PMOD-INTZ SPI |
---|---|
Pin 1 (Chip Enable) | CS |
Pin 2 (Not connected) | MOSI |
Pin 3 (MISO) | MISO |
Pin 4 (SCK) | SCK |
Pin 5 (GND) | GND |
Pin 6 (VCC) | VCC |
The final setup should look similar as shown below.
4. Power up the MAX32650FTHR by connecting it to your laptop using micro-USB. Connect MAX32625PICO to your laptop as well.
5. Open the file explorer. Drag-and-drop the pre-built hex file to the DAPLINK. If the transfer was not completed, update the firmware for the DAPLINK. Follow the steps here: https://github.com/MaximIntegrated/max32625pico-firmware-images/
6. Open PuTTY or other similar software. Check the Device Manager to set the correct COM port for the MAX32650FTHR.
7. Set baud rate according to the hex file used available in MAX32650FTHR_demo_ADXL355.hex:
Hex file | Baud rate |
---|---|
eval-adxl355-pmdz_maxim_dummy_example_max32650_adxl355 | 57600 |
eval-adxl355-pmdz_maxim_iio_example_max32650_adxl355 | 115200 |
The expected output viewed in the PuTTY is shown below.
The EVAL-ADXL355-PMDZ can be used with a Raspberry Pi.
The following is a list of items needed in order to replicate this demo.
In order to boot the Raspberry Pi and control the EVAL-ADXL355-PMDZ, you will need to install ADI Kuiper Linux on an SD card. Complete instructions, including where to download the SD card image, how to write it to the SD card, and how to configure the system are provided on the Kuiper Linux page.
Follow the configuration procedure under Configuring the SD Card for Raspberry Pi Projects on the Kuiper Linux page, substituting the following lines in config.txt:
dtoverlay=rpi-adxl355
To set up the circuit for evaluation, consider the following steps:
The original software example for the ADXL355 was developed on the ADICUP360 platform, and is a simple, terminal-based command line interface. This type of example program is being deprecated in favor of tinyiiod-based servers for embedded platforms, however this example is still available for reference here: ADXL355 Accelerometer PMOD Demo on ADICUP360.
The Libiio is a library used for interfacing with IIO devices and is required to be installed on your computer.
Download and install the latest Libiio package on your machine.
To be able to connect your device, the software must be able to create a context. The context creation in the software depends on the backend used to connect to the device as well as the platform where the EVAL-ADXL355-PMDZ is attached. Two platforms are currently supported for the EVAL-ADXL355-PMDZ: Raspberry Pi using the ADI Kuiper Linux and the ADICUP3029 running the no-OS ADXL355 demo project. The user needs to supply a URI which will be used in the context creation.
The iio_info command is a part of the libIIO package that reports all IIO attributes.
Upon installation, simply enter the command on the terminal command line to access it.
iio_info
iio_info -u ip:<ip address of your ip>
Example:
iio_info -u serial:<serial port>
Examples:
There are different commands that can be used to manage and control the device being used. The iio_attr command reads and writes IIO attributes.
analog@analog:~$ iio_attr [OPTION]...
Example:
analog@analog:~$ iio_attr -a -C
The iio_reg command reads or writes SPI or I2C registers in an IIO device. This is generally not needed for end applications, but can be useful in debugging drivers. Note that you need to specify a context using the -u qualifier when you are not directly accessing the device via RPI or when you are using the ADICUP3029 platform.
analog@analog:~$ iio_reg -u <context> <device> <register> [<value>]
Example:
iio_reg -u ip:<ip address> adxl355 0x02
Access the DMM panel to see the instantaneous reading of the x, y and z axis acceleration readings and the device temperature.
PyADI-IIO is a python abstraction module for ADI hardware with IIO drivers to make them easier to use. This module provides device-specific APIs built on top of the current libIIO python bindings. These interfaces try to match the driver naming as much as possible without the need to understand the complexities of libIIO and IIO.
Follow the step-by-step procedure on how to install, configure, and set up PYADI-IIO and install the necessary packages/modules needed by referring to this link.
After installing and configuring PYADI-IIO in your machine, you are now ready to run python script examples. In our case, run the adxl355_example.py found in the examples folder.
D:\pyadi-iio\examples>python adxl355_example.py
Press enter and you will get these readings.
Github link for the python sample script: ADXL355 Python Example
D:\pyadi-iio\examples>python adxl355_no_os_example.py serial:<serial port>,57600
In a Windows machine, you can check the port of your MAX32655FTHR and MAX32650FTHR via Device Manager in the Ports (COM & LPT) section. If your device is in COM8, you have to use python pyadi-iio/examples/adxl355_no_os_example.py serial:COM8,57600.
Press enter and you will get these readings.
Github link for the python sample script: ADXL355 Python Example
EVAL-ADXL355-PMDZ Design & Integration Files
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