This version (24 May 2023 03:02) was approved by Richmond Eustacio.The Previously approved version (24 May 2023 02:59) is available.
Table of Contents
MAX11205PMB1 Ultra-Low Power, Delta-Sigma ADC PMOD User Guide
The MAX11205PMB1 peripheral module provides the necessary hardware to interface the MAX11205 16-bit ADC to any system that utilizes PmodK-compatible expansion ports configurable for the GPIO interface. The IC is an ultra-low-power (< 300FA max active current), high-resolution, serial-output ADC.
Hardware
Power Supply Requirements
The voltage reference for the IC is supplied by a MAX6037 (2.5V) that is also on the module. The filtered power-supply voltage from the host can be optionally passed (jumper selectable) through a MAX8510 ultra-low-noise LDO, allowing empirical evaluation of performance with different power sources. For complete PMOD power specifications, please clickhere.
Serial-Digital Interface
The MAX11205PMB1 peripheral module interfaces with a host using a 2-wire serial interface. When an ADC conversion is complete, the IC pulls the data line low. The host must then supply a clock signal to shift out the conversion data.
Digital Interface (PMOD)
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 MAX11205PMB1 peripheral module can plug directly into a Pmod-compatible port (configured for SPI) through connector J1. Connector J1 provides a connection of the module to the host. The pin functions and pin assignments adhere to the Pmod standard recommended by Digilent.
| P1 Pin Number | Pin Function | Mnemonic |
|---|---|---|
| Pin 1 | N.C. | CS |
| Pin 2 | N.C. | MOSI |
| Pin 3 | Master In Slave Out | MISO |
| Pin 4 | Serial Clock | SCLK |
| Pin 5 | Digital Ground | DGND |
| Pin 6 | Digital Power | VDD |
Device Driver Support
There are two device driver solutions that are provided for controlling the MAX11205PMB1:
- MAX11205 no-OS Driver
- The MAX32655FTHR example application uses the MAX11205 no-OS driver and emulates the Linux IIO framework through the tinyiiod daemon library. This driver is used in bare-metal applications, typically running on low-power, embedded microcontrollers. The application communicates with the host computer via the serial backend, over a USB-UART physical connection. This facilitates rapid application development on a host computer, independent from embedded code development.
- MAX11205 Linux Driver
- The MAX11205 Linux driver is used in applications running the Linux operating system, typically on larger processors and SoC devices.
- The MAX11205 Linux driver uses the Industrial Input/Output (IIO) framework, greatly simplifying the development of application code via the cross-platform Libiio library, which is written in C and includes bindings for Python, MATLAB, C#, and other languages. Application code can run directly on the platform board, communicating with the device over the local backend, or from a remote host over the network or USB backends.
System Setup Using MAX32655FTHR
The MAX11205PMB1 can be used with the MAX32655FTHR.
Demo Requirements
The following is the list of items needed in order to replicate this demo.
- Hardware
- MAX32655FTHR or
- Micro-USB to USB cable
- PC or laptop with USB Port
- Software
- For MAX32655FTHR,
- Pre-built hex file “max11205_maxim_basic_example_max32655.hex” in max11205_max32655.hex
- PuTTY or other similar software
MAX32655FTHR
1. Connect MAX32655FTHR with the FTHR-PMD-INTZ. Note that MAXIM feather board should have stacking headers for feather board where the interposer board will be connected.
2. Connect MAX11205PMB1 to the FTHR-PMD-INTZ .
| MAX11205PMB1 (P1) | FTHR-PMD-INTZ SPI (P6) |
|---|---|
| Pin 1 (Not connected) | NC |
| Pin 2 (Not connected) | NC |
| Pin 3 (MISO) | MISO |
| Pin 4 (SCK) | SCK |
| Pin 5 (GND) | GND |
| Pin 6 (VCC) | VCC |
3. Connect MAX32655FTHR pin P0_22 (MISO) to P1_6.
The final setup should look similar as shown below.
4. Power up the MAX32655FTHR by connecting it to your laptop using a micro-USB cable.
5. Open the file explorer. Drag-and-drop the pre-built hex file “max11205pmb1_maxim_basic_example_max32655.hex” 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 correct COM for the MAX32655FTHR. Set baud rate to 57600 when running max11205pmb1_maxim_basic_example_max32655.hex available in max11205_max32655.
The expected output viewed in the PuTTY is shown below.
Application Software (All Platforms)
Hardware Connection
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 MAX11205PMB1 is attached. One platform is currently supported for the MAX11205PMB1: the MAX32655FTHR running the no-OS MAX11205 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.
For Windows machine connected to MAX32655FTHR:
iio_info -u serial:<serial port>
Examples:
- In a Windows machine, you can check the port of your MAX32655FTHR via Device Manager in the Ports (COM & LPT) section. If your device is in COM4, you have to use iio_info -u serial:COM4 as your URI.
- In a Unix-based machine, you will see it under the /dev/ directory in this format “ttyUSBn”, where n is a number depending on how many serial USB devices attached. If you see that your device is ttyUSB0, you have to use serial:/dev/ttyUSB0 as your URI.
IIO Commands
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:
- To look at the context attributes, enter this code on the terminal:
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 MAX32655FTHR platform.
analog@analog:~$ iio_reg -u <context> <device> <register> [<value>]
IIO Oscilloscope
Make sure to download/update to the latest version of IIO Oscilloscope found on this linkhttps://github.com/analogdevicesinc/iio-oscilloscope/releases
- Once done with the installation or an update of the latest IIO Oscilloscope, open the application. The user needs to supply a URI, which will be used in the context creation of the IIO Oscilloscope and the instructions can be seen from the previous section.
- Press refresh to display available IIO Devices, once MAX11205PMB1 appeared, press connect.
Debug Panel
Below is the Debug panel of MAX11205PMB1 wherein you can directly access the device attributes.
DMM Panel
Access the DMM panel to see the instantaneous reading of the voltage.
PyADI-IIO
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.
Running the example
After installing and configuring PYADI-IIO in your machine, you are now ready to run Python script examples. In our case, run the max11205_example.py found in the examples folder.
analog@analog:~$ python pyadi-iio/examples/max11205_example.py serial:<serial port>,57600
In a Windows machine, you can check the port of your MAX32655FTHR via Device Manager in the Ports (COM & LPT) section. If your device is in COM4, you have to use “python pyadi-iio/examples/max11205_example.py serial:COM4,57600”.
Github link for the Python sample script: MAX11205 Python Example
More information and Useful links
Schematics, PCB Layout, Bill of Materials
Additional Information
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resources/eval/user-guides/circuits-from-the-lab/max11205pmb1.txt · Last modified: 24 May 2023 03:01 by Richmond Eustacio