Antenna Analyzer Prototype Vector of EA4FRB
been a few months without publish news about project progress. This does not does it mean that the project has been stalled, which has happened is that I have decided to make some pretty significant changes and has taken some time to put into place.
The first change has been quite significant and "park" the solution based on the micro-controller and switch to PSoC5 STM32 ST Microelectronics. There have been many reasons for this decision, to begin to highlight the lack of visibility by Cypress in the availability and price of component, and specifically whether it really is interested in the amateur market and offer a competitively priced product. Quite the opposite is true of the STM32 family of STM which has tens of devices with both cores now Cortex Cortex M3 and M4, there are plenty of evaluation boards and development at competitive prices (the Discovery Kit is available $ 10), and have a very good support software. The STM32 is not as flexible and analog circuitry as high performance but is more than enough for most applications.
The second change has been decided to use a color TFT display. The monochrome display seemed very limited use to display graphics and being now in 2011 seems a bit anachronistic to use this technology. The good news is that you can find on the market size TFT display 2.8 "to 3.2" at very affordable prices, in fact even cheaper than monochrome. These displays also comprise a controller so it is very easy to control from a micro-controller as the STM32. Another important point is that you can find on the market "breakout boards", ie plates that make up the display and some additional hardware and connection type spike strip making it very easy to prototype with them. Also comment that some of the evaluation boards feature displays of this type. An example is the Mini STM32 V4 http://www.micro4you.com/store/mini-stm32-stm32f103-tft-lcd-board-v4/prod_164.html available at a price of $ 50.
The latest news is that I'm moving in the possible development as a commercial product (for the amateur segment.) The main features would be the pocket size (90x60x14.5 cm), 3.0 TFT display, Lithium Polymer, frequency range up to 200Mhz, USB and internal USB drive, and code open. I'll report in future posts on the blog about the progress of this implementation. In the event that the project not go ahead, publish in any case the necessary information and self-constructed source code for the analyzer in the coming months.
Moving into the more technical part, for the new prototype analyzer hardware I have used as a V3 and Mini STM32 STM32 STM32 Discovery Kit The Mini is one of the STM32 evaluation board that features a TFT display 2.8 " two USB connections, an SD slot, some LEDs and buttons, and a series of spike strips to access ports on the STM32. The downside is that there are very few ports available, although not a big problem for some software development. Reciemente have released version V4, which has many more ports available and it will be more suitable for prototyping the analyzer.
The STM32 Discovery Kit is used only for debugging functionality. The kit includes ST-Link, which is a debug interface that uses the SWI and allows external use, so I've configured this way to connect to the Mini STM32 for debugging.
The selection of software development tools has been a little headache. There are several commercial tools, free versions of commercial versions with different constraints, and completely free of GNU compilers. Finally, my decision was to use the "Lite" version of Atollic TrueStudio. This tool has no limitations on code size and the Lite version is fully functional development of analyzer software. The TrueStudio is based on the Eclipse IDE which makes it quite productive.
The original porting of the prototype analyzer for PSoC5 has been pretty straightforward. The library for the STM32 peripherals management provided by STM is very powerful allowing peripherals start very easily. To control the LCD I have used as base basic initialization routines provided by the manufacturer and from there I developed a library of graphics primitives. STM is developing a comprehensive graphics library but is currently available only in beta under NDA, so can not be used in this project. For
functionality USB, I used the STM library also provides for the purpose. It is also very easy to implement and so far I've tried the HID and Virtual COM clients. Are also available USB disk, audio, etc. As file system I carried the Chan FATFS currently using a SD hardware. Subsequently mount the file system on internal flash disk.
The user interface design and software implementation are not 100% complete but is already starting to take shape. The functionalities provided will be the impedance plots for the analysis of antennas analysis of cables and transmission lines through reflectrometría in the frequency domain, and Smith chart.
The basic graphics functionality is the most advanced impedance. The diagram will show up to two axes, for example to display the graph of R + X, or Rho + Phy, or any two variables selected by the user. It will provide up to two marks (Marker), selectable by the user or automatically. Also show the complete impedance parameters at the center frequency or any of the marks. Other features are, for example, the storage or retrieval of charts. The STM32 is enough memory so there is enough space for a number of features and future developments.
The following example screen, the first axis shows the ROE and second impedance module, and the two brands are activated.
Any comments or suggestions for this project are welcome.
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