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diff --git a/resources/jade/finals/ham/cw-decoder.jade b/resources/jade/finals/ham/cw-decoder.jade deleted file mode 100644 index bc8636b..0000000 --- a/resources/jade/finals/ham/cw-decoder.jade +++ /dev/null @@ -1,77 +0,0 @@ -extends layout-ham.jade - -block prepend menu - - var page = 'cw-decoder' - - var sections = ['Porting to PIC', 'Finishing', 'Future plans'] - -block subtitle - | CW Decoder -block subtitleDate - | January 2017 - -block subtitle-right - +githubLink('camilstaps/CWDecoder') - -block page - h4 Introduction - p. - We discuss a small PIC-based CW decoder, a great help for a beginning ham. - The base is taken from Budd Churchward WB7FHC's #[a(href='http://www.mypetarduino.com/ReadCode/readCode.01.html') Arduino-based decoder]. - My own source code, for a PIC16F88, is #[a(href='https://github.com/camilstaps/CWDecoder') on GitHub]. - - h4 Porting to PIC - p. - While the project is great, I was unable to resign myself to use an Arduino. - Arduino is nice for prototyping, but too many people use it as an end product, wasting space and resources. - Worst of all, they fail to learn principles of electrical engineering and programming on minimal architectures. - p. - Hence, I decided to port the project to a PIC microcontroller. - PIC is a wide range of microcontrollers developed by #[a(href='http://microchip.com') Microchip]. - For this project, a simple 8-bit chip is more than enough. - The only thing we need to look out for is that the clock is fast enough. - I went with the #[a(href='http://www.microchip.com/wwwproducts/en/pic16f88') PIC16F88] which has 5MIPS, for the simple reason that I had it in stock. - Anything will do. - p. - Porting the Arduino code (which is a C++ dialect) to C is relatively easy. - The only complication is the <code>millis()</code> function. - On Arduino, this returns the number of milliseconds since startup. - This is part of the Arduino bootstrapping code, which we do not have on PIC, so a small wrapper for this function had to be written. - The same functionality can be achieved with a timer and an interrupt service routine (which is, I assume, the way it works on Arduino as well). - p. - For the LCD I used a 4x40 display with green backlight. - It is #[a(href='http://www.ekenrooi.net/lcd/lcd.shtml') HD44780]-based but has two control chips, which can be turned on and off using two enable lines. - My #[a(href='https://github.com/camilstaps/HD44780_PIC') HD44780_PIC] C library can deal with this, as well as with 4- and 8-bit interface. - (This is all done through preprocessing <code>#define</code> statements so it does not slow down the code.) - p. - Other than these two points, porting the code was straightforward and no major changes have been made. - - h4 Finishing - p. - There was not much space left next to the display. - I had just enough space for the LED, the reset button and the volume button. - The LED is absolutely necessary on the front for feedback. - p. - The 4x40 LCD performs very well. - A 4x20 or perhaps 2x40 would do the job as well, but I wouldn't go smaller than that. - Sometimes characters are missed or noise is interpreted as a character, so you should expect that perhaps 80% of the character space is used for the actual text. - p. - There is no need to place the frequency potentiometer on the front because it should be fixed to your side tone. - I found that a high-precision potentiometer is very useful to adjust the frequency. - The bandwidth of the audio mixer is relatively narrow. - - h4 Future plans - p. - I intend to make the decoded text not only available on the LCD but also on the UART module. - The RX pin is used already, but one-way communication will be enough. - This way, another module could log QSOs to an SD card, another idea I have been playing with. - p. - Another addition I'd like to make is a fix-frequency button. - This would disable the automatic adaption to the current speed. - It could be pressed at the start of a QSO and released afterwards. - I hope that in this way the decoder can become less sensitive to background noise. - p. - Lastly, some status information would be nice on the LCD. - Concretely, I'm thinking about the estimated WPM. - This should be fairly simple to implement. - It could also be useful to have an accuracy estimation. - Figures that could be used for this are the standard deviation on the length of dits and dahs and the amount of jitter during a dit or dah. |