The following items are included in the update:

• This version was built with the bcm2835-1.25 library. All previous versions were built with bcm2835-17.
• This version was tested on 2013-02-09 raspian wheezy. The 2012-10-28 raspian wheezy was used for all previous versions.

iP Solu­tions originally created the Serial Peripheral Interface (SPI) command-line utility for the Raspberry Pi (www.raspberrypi.org) platform for the convenience of hardware debug and to indirectly add SPI functionality to scripting languages such as Bash and Python.

Although a C library exists for the Broadcom bcm2835 with an SPI Application Programming Interface (API) among other things, there are reasons to have a command-line utility, which can be invoked from a shell command line or from within a script. A command-line utility allows easy testing and debugging of SPI slave devices without having to develop a C executable. Additionally, it provides a simple way for bash and python scripts to access the SPI master of the BCM2835 on Raspberry Pi. Although the raspian distribution provides GPIO libraries with the included python installation it doesn’t include an SPI library. spincl, on the other hand, can be invoked from a python (or bash) script.

Check the original post for a full explanation of the Raspberry Pi SPI command-line utility and to download the latest version.

The post Raspberry Pi SPI Command-line Utility 1.3.1 Available appeared first on iP Solutions.

The following items are included in the update:

• Bug Fix:  A bug in the way the number of transmit bytes was calculated has been fixed.  Previously, if the total byte length of the transfer was greater than the number of specified xmit bytes then an attempt to access command-line arguments beyond the number available would occur, which causes a segmentation fault.
• suid bit is now set in the install target of Makefile.

iP Solutions originally created the Serial Peripheral Interface (SPI) command-line utility for the Raspberry Pi (www.raspberrypi.org) platform for the convenience of hardware debug and to indirectly add SPI functionality to scripting languages such as Bash and Python.

Although a C library exists for the Broad­com bcm2835 with an SPI Application Programming Interface (API) among other things, there are reasons to have a command-line utility, which can be invoked from a shell command line or from within a script.  A command-line utility allows easy testing and debugging of SPI slave devices without having to develop a C executable.  Additionally, it provides a simple way for bash and python scripts to access the SPI master of the BCM2835 on Raspberry Pi. Although the raspian distribution provides GPIO libraries with the included python installation it doesn’t include an SPI library. spincl, on the other hand, can be invoked from a python (or bash) script.

Check the original post for a full explanation of the Raspberry Pi SPI command-line utility and to download the latest version.

The post Raspberry Pi SPI Command-line Utility Update appeared first on iP Solutions.

Although a C library exists for the Broadcom bcm2835 with an SPI Application Programming Interface (API) among other things, there are reasons to have a command-line utility, which can be invoked from a shell command line or from within a script.  A command-line utility allows easy testing and debugging of SPI slave devices without having to develop a C executable.  Additionally, it provides a simple way for bash and python scripts to access the SPI master of the BCM2835 on Raspberry Pi. Although the raspian distribution provides GPIO libraries with the included python installation it doesn’t include an SPI library. spincl, on the other hand, can be invoked from a python (or bash) script.  

Description

spincl is a command-line utility for executing SPI commands with the Broadcom bcm2835 from a shell command line (or script).  The utility is based on the bcm2835 C library developed by Mike McCauley of Open System Consultants, http://www.open.com.au/mikem/bcm2835.  It was built with version 1.17 of the bcm2835 library and tested on a Raspberry Pi single-board computer model B with an iP Solutions designed I/O board, which contains SPI accessible ADC and digital I/O expansion.

Invoking spincl results in a full-duplex SPI transfer.  Options include the the SPI clock frequency, SPI Mode, chip select designation, and chip select polarity.  Invoking spincl requires root privilege.  If no command-line arguments are included or if there are any command-line argument errors, a “usage statement” will be printed on stdout similar to the Usage documentation below.

Usage

spincl [options] len [xmit bytes]

Invoking spincl results in a full-duplex SPI transfer of a specified number of bytes.  Additionally, it can be used to set the appropriate  GPIO pins to their respective SPI configurations or return them  to GPIO input configuration.  Options include the SPI clock frequency,  SPI Mode, chip select designation, chip select polarity and an  initialization option (spi_begin and spi_end).

spincl must be invoked  with root privileges.  However, as of version 1.3.0, although the make install target included in the Makefile installs spincl with a root owner, it also sets the suid bit so that users other than root may invoke spincl without a sudo prefix.

The following are the options, which must be a single letter  preceded by a ‘-’ and followed by another character:

• –ix where x is the SPI init option, b[egin] or e[nd].  The begin option must be executed before any transfer can happen.   It may optionally be included with a transfer.   The end option will return the SPI pins to GPIO inputs.   It may also optionally be included with a transfer.
• –mx where x is the SPI mode, 0, 1, 2, or 3
• –cx where x is the exponent of 2 of the clock divider.   Allowed values  are 0 through 15.  Valid clock divider values are powers of 2.  Corresponding frequencies are specified in bcm2835.h.
• –sx where x is 0 (CS0), 1 (CS1), 2 (CS1&CS2), or 3 (None)
• –px where x is chip select polarity, 0(LOW) or 1(HIGH)

len: The number of bytes to be transmitted and received (full duplex).

xmit bytes:  The bytes to be transmitted if specified.  If none are specified, 0s will be transmitted, which may be the case when only the received data is relevant.

Examples

Use spincl to just intialize the SPI pins: spincl –ib

Use spincl to intialize the SPI pins and read three bytes (note xmit bytes are not specified).  Mode is 2, clock frequency is 15.625Mhz (see bcm2835.h), chip select is 0, and polarity is active low:  spincl –ib –m2 –c4 –s0 –p0 3

Use spincl to transmit 2 bytes (specified) and read back 2 bytes, which may or may not be relevant.  Mode is 1, clock frequency is 7.8125MHz, chip select is 1, and polarity is active high.  Note that no initialization has been specified so SPI pins must have been previously initialized:  spincl –m1 –c5 –s1 –p1 2 0x5c 0x13

Use spincl to read two byte with mode 3, clock frequency of 15.625Mhz, and no chip select (done by user some other way).  When the SPI tranfer has been completed, the SPI pins will be returned to GPIO inputs:  spincl –ie –m3 –c4 –s3 2

Use spincl to just return the SPI pins to GPIO inputs:  spincl –ie

Build

Of course the spincl executable will work as is.  However, if you want to make edits to the source, a Makefile is included to rebuild the executable.  The Makefile assumes that the bcm2835 library has been installed.  In other words, bcm2835.h is in /usr/local/include and libbcm2835.a is in /usr/local/lib.  To “make” the executable, type make at the command-line prompt from the spincl directory.  Again, the version of the  bcm2835 library that was used to build the executable included in the download is 1.17.  You may wish to try building spincl with the most current version.  An example “install” target is included in the Makefile, which installs spincl in /opt/bin with root ownership and group with appropriate privileges, including setting the suid bit.  Edit them as required for your application.

Get Free Download

Click here to download latest update of spincl.tar.gz     Download

Place the tarball file in the desired directory and then execute:

• tar –xzvf spincl.tar.gz (spincl_1_3_1.tar.gz as of 7/31/13)

to get the expanded source directory.

Updates

• Version 1.3.0, 5/19/24:
  • Bug Fix:  A bug in the way the number of trasmit bytes was calculated was fixed.  Previously, if the total byte length of the transfer was greater than the number of specified xmit bytes then an attempt to access command-line arguments beyond the number available would occur, which causes a segmentation fault.
  • suid bit is now set in the install target of Makefile.
• Version 1.3.1, 6/25/13:
  • This version was built with the bcm2835-1.25 library.  All previous versions were built with bcm2835-17.
  • This version was tested on 2013-02-09 raspian wheezy. The 2012-10-28 raspian wheezy was used for all previous versions.

iP Solutions in no way warrants or guarantees correctness of the downloaded code or that it’s bug-free.

The post SPI Command-line Utility for Raspberry Pi appeared first on iP Solutions.

iP Solutions brought extensive knowledge of Embedded Linux DSP systems hardware and software to the Nevada Nanotech Systems (NNTS) project for explosive chemical and radiation threat detection and  analysis. The project, CScout, was targeted for shipping container security.

Previous experience with complex embedded control and data acquisition systems enabled iP Solutions to immediately begin contributing to this project.  The primary goal was to design both hardware and software for using an NNTS Molecular Properties Sensor (MPS) to collect, analyze and present explosive chemical vapor threat data.  Additionally, radiation spectrum data was to be collected and analyzed for any radiation threat components.  This system was to be controlled and results communicated remotely through a wireless interface, the Maritime Asset Tag Tracking System (MATTS).  Also, a hardwired network connection was to enable more extensive maintenance and engineering modes with web-based and terminal based interfaces.

The CScout system was successfully completed with impressive measurement results. This system will be used for demonstration of NNTS sensor capabilities to potential customers.

MPS Sensor

The NNTS CScout project was designed around requirements to stimulate and measure the output of various types of NNTS MPS sensor devices. The MPS devices typically contain one or more tiny specialized cantilevers for performing calorimetric, temperature and mass measurements. These cantilevers are tiny diving board like fingers that protrude from bulk silicon and are surrounded by air. These are considered MEMS (micro electro mechanical systems) or NEMS (nano electro mechanical systems) depending upon the dimensions involved.

 CScout System

At the core of the CScout system is an embedded Linux General Purpose Processor (GPP) platform with a slave Digital Signal Processor  (DSP).  This was implemented with a TI OMAPL137 which also includes other IP cores such as Serial Peripheral Interface (SPI) masters (2) and Pulse-width Modulator PWM channels (6).  These cores were used to drive additional iP Solutions-designed circuitry for implementing the calorimetric, temperature and mass measurements.

Services Performed for NNTS

iP Solutions performed the following tasks for the Nevada Nanotech Systems CScout project:

• Hardware and Software specifications
• Evaluation of laboratory proto-type testing
• Design of new electronics
  • MPS piezoelectric cantilever stimulus and response at 10 microsecond per stimulus-measurement cycle (1 channel)
  • MPS cantilever resistor stimulus and response at 15 microsecond per stimulus-measurement cycle (12 channels)
  • SPI driver circuits (Linux and DSP)
  • Power system
  • Radiation sensor interface
  • MATTS wireless communications interface
  • Pump controller (2)
  • Fan controller (2)
  • Heater controllers (4)
  • Peltier controller (1)
  • Integration of OMAPL137 processor board
• Design, build and test Printed Circuit Boards (10)
• Design and write software
  • Boot loader configuration to mount USB root file system
  • Linux kernel enhancements
    • kernel SPIdev enhancements to handle non-standard chip select scheme
    • USB drive implementation
  • Linux Drivers
    • SPI
    • PWM
    • General-purpose OMAP register access
    • Modified / enhanced an existing General Purpose I/O (GPIO) driver
  • Linux daemons (services)
    • State machine central controller
    • Proportional Integral Derivative (PID) / PWM service provides access to and controls the heaters (4) and pumps (2) of the CScout.  Also, the daemon monitors ambient temperature and humidity.
    • MATTS service, which features the ability to process requests from the Maritime Asset Tracking System.  The MATTS service continually monitors and parses requests, and then based on specific requests passes control to user-designated and user-designed scripts for appropriate processing.
  • Linux utilities: some utilities are low-level “wrappers” for accessing the drivers.  Other utilities, built on the lower-level utilities, provide higher-level functionality.
  • DSP drivers
    • DSP SPI driver (high speed)
    • Precise timing control
  • Protocol drivers, which consist of a pair of executables, one of which operates in the OAMP L137 GPP and one that operates in the DSP.  The GPP executables provide the interface to the protocol drivers, while the DSP executables directly interface to the CScout hardware to drive and acquire data from an MPS.
  • Radiation detection and analysis
  • Web server and web application implemented with Cherry Pi for maintenance and engineering interface.
  • Self-test
• Test protocols for testing drivers and controllers written in both Python, Bash and C code (many)
• Production protocols for MPS (many variations) written in C code
  • Calorimetric (up to 12 channels)
    • Cantilever resistor current sweep
    • Cantilever resistor power sweep
    • Cantilever resistor voltage sweep
    • Cantilever resistance measurement
    • Cantilever voltage measurement
    • Cantilever resistor Power measurement
    • Peltier heating/cooling control
    • Pump control
    • Fan control
    • Heater control
  • Piezoelectric cantilever (many variations)
    • Frequency sweep
    • Auto-null
    • Auto-peak detection
    • Integrate with resistor measurements
    • Peltier heating/cooling control
    • Pump control
    • Fan control
    • Heater control
  • Implement GIT software revision control system
• Build and test complete systems and software protocols(10)
• Training
• Documentation
• Final report

The post Embedded Linux DSP System for Chemical and Radiation Threat Detection appeared first on iP Solutions.

Link to Final Report at the DRRC

The post Invitation to Join DRRC Industrial Controls Experts Group appeared first on iP Solutions.

Crop irrigation requirements vary in time with weather and soil conditions. Precision
irrigation provides a means for evaluating a crop’s water requirements and a means for
applying the right amount at the right time. Often in the literature, precision irrigation is referred to as irrigation scheduling: That is scheduling based on environmental data, whether that data comes from local field sensors or from more global sources such as regional meteorological information.

Applying precision irrigation practices offers significant potential for saving water,
energy, and money. Further, it has the potential to increases crop yield. There is an
additional positive environmental impact from precision irrigation in that farm runoff, a major source of water pollution, can be reduced.

While precision irrigation has value for all types of irrigation in any region of the world, this paper focuses on the irrigation of California agriculture, which uses nearly 80% of the state’s water and more than ten billion Kilowatt hours of electricity annually. That is enough electricity to power one million typical American households each year. The approximate power plant capacity required to power California irrigation through the months of May through October is 2500 MW, which is equivalent to 250 Min-Nuke power plants running at an average of 10MW each. The carbon footprint associated
with the power is approximately six million metric tons of CO² per year.

See full paper…

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