BUG External Controller Initial Value not honoured

[Rex]

That would require more pins than the existing TRS jack has. So yes, it would require new hardware.

 

[ChristThePhone]

Yes, but that only works with TS plugs. But expression pedals require TRS plugs. All three contacts are in use. Switch-open is identical to toe-up on the pedal. Switch-closed is identical to toe-down. The hardware has no way to know whether you've pulled out the plug, or just rocked the pedal forward.

There could be a technical solution even without extra IO lines used (as long as the TRS jack has a switch, does anyone know?) but it would work unreliably if high-z expression pedals were used.

 

[Rex]

There could be a technical solution even without extra IO lines used (as long as the TRS jack has a switch, does anyone know?) but it would work unreliably if high-z expression pedals were used.

It's a TRS jack. Even if it had a separate switch, there's no circuitry to sense it.

 

[GlennO]

Usually, „detection“ is done with the ring. That’s how it works for active guitar electronic, see here.

That's an unswitched jack though. As I understand it, use of an unswitched jack is the root of the problem here. I'm suggesting using a switched TRS jack to solve this problem in a future hardware revision.

 

[ChristThePhone]

It's a TRS jack. Even if it had a separate switch, there's no circuitry to sense it.

if it had a switch it could be sensed by the voltage drop at a series resistor when the pedal is plugged. the AD converter would then read the max voltage only if no pedal was plugged. the problem with that approach is that the voltage drop would be dependent on the impedance of the expression pedal. could be calibrated but doesn't work well with pedals with a lot higher impedance than the series resistor.