Nerds assemble: programming the ATmega88PA?

PolarityMan

Nice work.

olafgarten

I missed this post, but if you have any questions I have a bit of experience programming a 328.

I'd switch to using the Arduino MIDI library as soon as possible, I also have worked with MIDI on a seperate project and it's pretty weird, you might find some weird issues that don't make sense that they have probably accounted for in the Arduino library. 

digitalscream

olafgarten said:

I missed this post, but if you have any questions I have a bit of experience programming a 328.

I'd switch to using the Arduino MIDI library as soon as possible, I also have worked with MIDI on a seperate project and it's pretty weird, you might find some weird issues that don't make sense that they have probably accounted for in the Arduino library. 

Yeah, I'm planning to rewrite it at some point so that it responds to CCs as well. I'm also not sure about the MIDI Thru functionality - haven't tried it, but I'm not convinced that the code involved will work 100%.

digitalscream

As a final update...this episode has inspired me to make a delay pedal. Basically, I can't find any pedals that do everything I want, so I'm going to start off by taking the Joyo Quattro I've got in a drawer somewhere, rip the guts out, replace the pots with digitally-controlled pots, connect it all up to an Arduino of some sort, put a display on it, and write some code to control it all via MIDI. If that works (and I've got enough spare ports on the Arduino), I'll get another Quattro and do the same but control it from the same Arduino.

The idea is that there were many things I liked about the Eventide Time Factor I had, but all of the non-digital-delay modes were pretty awful. I love all the sounds in the Quattro and it's got proper trails bypass, so...I'll basically make a Time Factor out of them.

In fact, it may not even end up being a pedal - I might stick it in the back of the preamp/power amp rack.

PolarityMan

How important was ahving the original source code to making this work? Where I'm going with that question is....do you think it is liekly you could mod a JVM in the same way to reduce the switching lag?

digitalscream

PolarityMan said:

How important was ahving the original source code to making this work? Where I'm going with that question is....do you think it is liekly you could mod a JVM in the same way to reduce the switching lag?

Immensely important - for the sake of achieving a good result in a reasonable amount of time.

Without the source code, I'd have had to reverse-engineer the circuit to figure out which relays did what, and from there work out the correct combination of relays needed to switch each channel. Then I'd have to write some code to handle all the controls (both from the front panel and via MIDI).

That would've been pretty time-consuming, and could potentially have resulted in me doing something silly that might damage the preamp.

With regard to the JVM...I'm sure an amp tech would be able to advise on the right combination of relays for each channel (although the different modes on each channel make it much more complex). Also, there's the fact that we don't know what the controller is - it's guaranteed to be a lot more complex and involved than the simple 3-channel switching on the X88R. You also have to consider the fact that there's a reason they put that gap in; it covers a thump when switching via MIDI. Take away the gap, and you might end up with something even more annoying.

That brings me to the absolute most important aspect here - the fact that it's an Atmel chip (ie one of the most popular hobbyist microcontrollers around) is what made this possible.

Emp_Fab

I'm in awe.

In the same way a farmer would be watching two wizards discussing magic spells might be.

WiresDreamDisasters

I'm in awe too.

In the same way two blacksmiths would be watching two flooring specialists install some laminate!