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P2 IAMBIC Mode B Morse Code App — Parallax Forums

P2 IAMBIC Mode B Morse Code App

PropGuy2PropGuy2 Posts: 358
edited 2023-12-10 03:30 in Propeller 2

All - I have been wanting a P2 IAMBIC Mode B keyer app for some time now.

I finally cobbled together some code for the P2 Module EC. A few short lines of code you can easily embed in your single COG application. It emulates Mode B, but does not have the true DIT and DAH memory function. Simplicity rules.
The app code snippet has some helpful features & notes, some of which you probably will not need, Change to suit: included, DIT input pin, DAH input pin, VGA display graphic option, LED56, LED57 option, Keyer Line output option. Speed equation(s)s function. They are included for your reference.
To use simply load the P2 IAMBIC Keyer Demo onto your P2 Module EC. The Io pin outs are preset, but you can change them to suit your circuit. The Demo also uses JM Sine.spin2 Sine wave application. The CW speed is set to 10 WPM, but is easily changed in the Demo
Four files are included. Have fun...

Comments

  • ke4pjwke4pjw Posts: 1,082

    Well, time for me to dig out my paddles :) Very cool project!

  • PropGuy2PropGuy2 Posts: 358
    edited 2023-12-10 03:27

    Additional user notes:
    (1 ) The DIT and DAH input pins should have a Ferrite Bead (FB) or SMD 100uH ferrite inductor placed in line to protect the P2 pins in a high RF environment.
    (2 ) The Audio out (Sine wave Demo by JM ) tone Pin out line should have a .1uF ceramic cap (104) into a LM386 or LM380 audio amplifier IC. Use a 220uF cap inline to drive your 8-Ohm speaker. (see the data sheet ) The music tone frequency, volume & duration (DIT time) are all adjustable in the application demo.
    (3 ) The CW Line out should have a driver IC, like SN75468. This is a 7-channel Darlington array with clamp diodes included. (See the data sheet ) The 3v3 drive input at 1mA is compatible with the P2. The open collector voltage can be from 6v0 to 100v0, but typically 12v0 should be used.
    (4 ) The IAMBIC logic does not follow the strict Mode-B protocol. That would be a true DIT and DAH paddle memory feature. Instead, any following DAH DIT DAH DIT pattern would have you holding the DIT and DAH paddles closed the whole time of the character sent. Simplicity rules.
    (5 ) That said, the IAMBIC code does not use any recurring code methods. The stack should never over run.
    (6 ) The IAMBIC code app can be stand alone , or embedded in you application. Have fun.

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