IK0WRB Radio Site - PIC Projects

IK0WRB Keyer version 2.2

Released June 30, 2001

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General description

To know what is a keyer and what it's supposed to do, and also for a general description of the circuit I designed, please read the page about version 1.0 of the keyer.
Version 2.2 uses the same circuit of version 2.1, with the possibility to use a rotary switch either binary (16 positions numbered 0 to F) or BCD (10 positions numbered 0 to 9).
Moreover you can install either a 2 MHz or a 4 MHz crystal, depending on availability and price (I was very surprised to find that in my town 2 MHz crystals cost often three times a 4 MHz piece and are far less common).
I changed also many other things in the program, as described below.

The circuit

What follows is the circuit of the IK0WRB Keyer version 2.2

If you need this drawing at a higher resolution, press here.

The components list

The program

You can download here the hex module you need to program the Microchip PIC 16F84 you need for keyer. This is the software for version 2.2 of the keyer. New versions of the circuit (and related software) may be released in the future.


The zip archive contains the circuit drawing, this page and the hex module.

How to use the keyer

The use of the keyer is basically identical to version 2.1 of the keyer, but I totally rewrote the manipulation (iambic) routine, after some very high speed CW enthusiasts criticised a bit my keyer. I think now iambic is ok even for these strange chaps :-)
Due to difficulties to find 4-bits (thus 5 pins) 16-positions binary rotary switches, I mapped the positions A through E also on positions 5 to 9, that were unused before. So now, for example, to set audio on/off you can rotate the switch to 5 or to A, at your choice. This means that you can now also install a 4-bits (5 pins) 10-positions BCD switch, witch is more easy to find.
For the same market reason, I decided to support both 2 and 4 MHz quarz crystals, but for this you must tell the chip in some way (no, wispering doesn't work...) what crystal you are using. Since I got 2 unused pins, one of them is used now for this purpose. So, leaving pin 13 of the 16F84 free (logic 1) tells the chip that you are using a 2 MHz crystal (this is compatible with previous versions of the circuit), while connecting pin 13 to ground (logic 0) tells the chip that you are using a 4 MHz crystal.
All these changes were possibile because I changed the way to compute delays for each transmitting speed. Up to version 2.1 I used a pre-computed table stored in program memory, but now I execute a division routine and the space occupied by the table is now used for real istructions.
Thus I could add also a new feature to direct mode: pressing the button will trasmit a 5 seconds carrier, very useful for tuning.
I prolongued also the timeout for sleep mode, from the very short 33 seconds to a more normal 2'45". This doesn't affect the way you use the keyer, it's only a psycological trick: the keyer doesn't look dead while listening in a CW QSO.
Finally, I measured the actual trasmitted speed of the keyer and found it was about 9.8% slower than it should have been. Not a real problem, but I tuned delay constants anyway.
The following table shows how to operate the keyer version 2.2.

Operating version 2.2 of the IK0WRB Keyer
Rotary switch
Status LED color Left paddle Right paddle SET button
0 Sleep Off No effect No effect No effect
1 Ready Green while rx.
Red while tx.
Yellow if tx local.
Dot Dash Send single CQ message
2 Speed Yellow Decrease speed Increase speed Sound current speed
3 Weighting Yellow Decrease weight Increase weight Sound current weight
(Wn or Wn.5)
4 TX Green if disabled.
Yellow if enabled.
Enable transmitterDisable transmitter Sound status
(TY or TN)
5 or A Audio Green if disabled.
Yellow if enabled.
Enable audio monitor Disable audio monitor Sound status
(AY or AN)
6 or B Beacon Green if message present.
Off if no message.
Starts Beacon sequence.
During carrier: immediate call.
During call: go to carrier.
During carrier: more carrier.
Starts Beacon sequence.
During tx or carrier: stops Beacon sequence.
Autostart beacon sequence at power on
7 or C CQ Green if message present.
Off if no message.
Starts CQ sequence.
During pause: immediate CQ.
During CQ: go to pause.
During pause: more pause.
Starts CQ sequence.
During CQ or pause: stops sequence
8 or D Direct Green Carrier while pressed Carrier while pressed 5 seconds carrier
9 or E Enter Green Store a dot Store a dash Single pressure: insert inter-word space.
2 consecutive pressures: delete last char.
Store an inter-character space when pausing 0.25 sec.
F Sleep Off No effect No effect No effect


Changes from version 2.1 to 2.2 are in bold.

Future releases

I had said that no further developments were possibile. I was wrong :-)
Meanwhile on OM said it has extended the keyer circuit. You can look at this design on the YO7LHC page.
v1.0 v2.0 v2.1 YO7LHC Beacon PIC Projects Index IK0WRB Home page

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