If the current source code posted is up-to-date, I don't think an external keyer will help. ?
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The pin connected to the key input is being polled within a GUI process by code in sbitx_gtk.c . ?Normal processes running on a loaded non-real-time Linux kernel on a single-core Raspberry Pi can have maybe up to 20 milliseconds or more latency when polled without interrupt handlers or kernel mods. ?This is a bit too long for decent CW keying at common WPM speeds. ?The key input handling could perhaps better be done in an interrupt routine, or using pigpio time-stamps to de-jitter the timing. ?Or possibly with some real-time kernel modifications to the standard Raspberry Pi Linux distribution.
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73, Ron, N6YWU
