Connecting the Keyer

Primary Pins

Here are the main pins you need to connect up to get started:

Left Paddle – pin 2 – connect to your left paddle (grounding will send dits)

Right Paddle – pin 5 – connect to your right paddle (grounding will send dahs)

Transmitter Key – pin 11 – goes high for key down; use to drive a transistor to ground the TX key

Sidetone – pin 4 – this outputs square wave sidetone to drive a speaker (schematic coming out shortly for driving with a transistor). The sidetone can be deactivated on transmit for transmitters that generate their own sidetone.

The command button – pin A1 and at least R7, see schematics and the Memory buttons section for expansion of this

Memory buttons - up to 12 memory buttons can be added to the command button. Add buttons and resistors R8, R9, R10, etc. (You can do just a few memory buttons, all 12, or none at all. See schematics for details.

Optional Pins

Additional pins you may be interested in for other functionality:

PTT (push to talk) - described in more detail in the wiki

Additional TX Key lines - add support for multi-transmitter capability

Potentiometer Speed Control – pin A0 – connect one end of the pot to +5V, the other end to ground, and connect the wiper to pin A0 to quickly adjust the speed

Rotary Encode Speed Control – no default pins are defined; two pins are required, defined by the following options in keyer_pin_settings.h:

rotary_pin1 
rotary_pin2

Changing Pins

Almost all pins can be easily changed if desired in keyer_pin_settings.h. Be careful not to assign the same pin to multiple needs.

Please note the following exceptions:

If using a PS2 keyboard, the clock pin must remain at pin 3 due to interrupt requirements.
If using an Adafruit I2c display, pins A4 and A5 are needed for I2C.