Whats The Deal With Dsl40cr Pedal Pedl-91016

[TheKman76]

Much kudos, well done.

 

[LAAF]

I finally got a PEDL-91016 and was able to scope it to see how it works. The line switches between 0V and 6V with data riding on the 6VDC. It appears to draw about 40mA of current since the voltage drop goes from 12V to 6V across a 150 ohm power resistor. The data bits are about 200 microseconds wide. Data is transmitted both when the button is pressed and released. It appears that the button status is sent to the amp and the amp responds with data to update the LEDs after about 8 milliseconds. I can see the data change based on the channel being selected. Pretty simple with a slow data rate for reliability. Since this footswitch needs power from the amp, I can see how a slightly poor connection (via the 2 conductor cable) could result in erratic behavior. It could also be caused by cheap capacitors in the footswitch that lose capacitance (increase ESR) as they age. This would affect the ability to hold charge and keep the V+ voltage above the needed threshold to operate reliably. Just a thought. You can see the voltage droop when the data is being sent as expected since the voltage is held up with a diode into a capacitor on the FS.

Also, the PEDL91016 uses the same low-cost ST Micro STM8S005K6 used in the DSL40CR/DSL100HR amp, which makes sense since they talk to each other.

 

[LAAF]

Here is a comparison of the 4 modes (Clean, Crunch, OD-1 and OD-2). You can see the data change between the modes.
The Master and Fx Loop commands are always the same to the amp and it toggles based on the current state. On my MIDI FS, I had to keep track of this.