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CW Keyer – Assembly and programming notes



Board Layout

PIC Basic code

Compiled PIC code (hex file)


 The assembly of the CW Keyer is straightforward and all parts are shown on the PCB layout diagram and parts list.

1)    Insert the IC socket first ensuring it is aligned with the notch towards the DB9 socket

2)    Insert all fixed resistors and capacitors checking that C7 is 10n (103) and that C1` is the polycarbonate timing capacitor (ivory body)

3)    Insert the regulator (U2), the keying transistor (Q1) and the diode D1 – check the orientation of each of these components.

4)    Insert the 4MHz resonator (RES1) – it can go either way round

5)    Insert J2 making sure the legs are properly soldered

6)    Insert the remaining large components – K1, S1, J1 and R9.

7)    The push switches S2 and S3 are wired to the board so they can be used wherever is convenient for operation

8)    Before inserting the PIC (U1) connect a supply to J3 (9 – 12 volts , it is not critical) switch on and check that you have 5 volts at pin 14 of U1

9)    If all is well, switch off and insert the PIC into its socket, ensuring the notch is towards K1

10)  That is the assembly complete.


1)    Connect a speaker or the sounder to SKR1

2)    Insert a paddle key – either a single paddle  or a dual paddle squeeze key into J1

3)    Operating the key should produce dits and dahs from the sounder and with a squeeze key it will operate in Iambic mode, R9 will adjust the keying speed

4)    If the range of keying speed adjustment is inadequate it is possible to reduce R6 to increase the upper limit or to increase the value of R6 to reduce the lower limit.  Do not reduce R6 below 100 ohms otherwise the keyer may lock up.


5)    Memory Operation:

A quick press and release of S3 should send the CQ routine including your callsign

A quick press of S2 should send the programmed contest report including a serial number (ur rst 599001 rst 5nn001 tu)

A press and hold (for more than 1 second) of S2 will send a contest signoff (73 gl callsign qrz) this also automatically advances the contact serial number and stores it for the next contact – this is stored in non volatile memory so the keyer can be turned off but the serial number is retained.

Pressing and holding S3 (for more than 1 second) puts the keyer into programming mode

In addition to these functions there is a beacon function provided. This will put the keyer into a continuous mode sending a pre-programmed beacon message and then holding key down for 20 seconds. This repeats until the keyer is switched off. To access this mode press and hold both buttons simultaneously for at least 1 second. This function is NOT reprogrammable by the RS232 port and must be hard programmed.


The keyer memories can be accessed to reprogram them via a serial port from a PC. The parameters for the port are 9600 baud, 8 data bits, 1 stop bit, no parity – I use “puTTY” as a program for access as it is freely available from the internet.

1)    Connect the keyer to a serial port and activate whatever program you normally use to communicate via this port

2)    Switch the keyer on and hold S3 for at least a second and you should see an introductory menu displayed on your monitor

3)    Enter whichever letter you want for the memory to be changed (eg “C” for callsign)

4)    The keyer will prompt you to enter the first character (any valid letter or number or /  or ?); as you enter the character it will be written to memory and you will be prompted to enter the next character – do not try to type ahead as it will just ignore you!

5)    End data entry with “~” ; if you have exceeded the memory space available the program will end automatically and nothing else will be entered

6)    When you finish data entry the program terminates and returns you to normal keyer operation; to change another memory it is necessary to run the complete procedure again.

7)    It is not possible to change the beacon memory (lack of program space on the PIC to implement this)

8)    There are some shortcut keys to insert certain prosigns, your callsign and the contest serial number into the memory – this is done to save space:

a)    Callsign – “@”

b)    Serial Number – “#”

c)    KA – “:”

d)    KN – “;”

e)    AR – “<”

f)     BT – “=”

g)    SK (VA) – “>”

h)   And just a reminder – end of message “~”

That’s about it, any problems give me a call; if there are any changes to the firmware I will reprogram your chip for you and if you want to change the beacon facility let me know and I will do that for you as well

Barry Horning  GM4TOE