Boss DD-20 Mods?

[FosterF]

I got a Boss DD-20 today and I want to do the BPM readout mod (Mod that sends the BPM readout of the pedal to other pedals that take tap tempo).  I know I need to hack into the clock to do this, but I'm not sure exactly where my two points of contact need to be.  Does any have any ideas? or has anyone done this before?  The main clock chip is a M12L64164A-7T. 
Any help would be greatly appreciated! Thanks guys.
-Foster

[Dimitree]

hi, DD-20 service manual is available for free somewhere in the web (I'm sure), I should have it somewhere on my HDD, if you can't find it let me know and I will search

[mth5044]

There is a forum called Boss Area full of people who know a frightening large amount of stuff on just about every boss pedal. Might want to try searching or posting there if you can't seem to find what you're looking for on this forum.

[The Tone God]

If this function is not already in the firmware then it is highly unlikely you will be able to add it. Its a DSP pedal where most of the work is done in software. It is not like a BBD based which has an external clock source you can tap into. The M12L64164A is not a clock chip, it is external memory and of no use for this function. This is not going to be like connecting a few wires. You would need to modify the firmware which is HIGHLY unlikely.

Andrew

[PRR]

> The main clock chip is a M12L64164A-7T.

That's a memory chip, not a clock chip.

Something else is clocking it.

The signal on the CLK pin is probably not directly related to delay time. (When they use a RAM chip they can read and write to different addresses in alternate cycles... what you want is the difference of addresses divided by the sample rate.)

Agree with Andrew. Look for a product which has this feature built-in.

[nocentelli]

There is a forum called Boss Area full of people who know a frightening large amount of stuff on just about every boss pedal. Might want to try searching or posting there if you can't seem to find what you're looking for on this forum.

The forum shut down quite a long time ago.

[Dimitree]

the easiest way I could think (but still quite difficult and not worth the effort) could be "parsing" that info from the LCD (if the LCD shows it), if the LCD is a standard type, you could sniff the infos that the uC sends to it, and use them. That would require a lot of digital programming skills. But I'm not saying that it is possible, but maybe is.
Or, if you set the tempo with your foot on the DD20, you could read that pulses with a uC and traslate them to usefull stuff (just like DD20 does internally). This is doable for sure (for example I added Midi capability to my DD20)

update:
now that I think about it, if I'm not wrong the DD20 also has a led that indicates the delay time.. You could simply take that pulse and traslate it into bpm (but you will need to know the right note division used), again using a uC.

[mth5044]

There is a forum called Boss Area full of people who know a frightening large amount of stuff on just about every boss pedal. Might want to try searching or posting there if you can't seem to find what you're looking for on this forum.

The forum shut down quite a long time ago.

[Jpschefano]

the easiest way I could think (but still quite difficult and not worth the effort) could be "parsing" that info from the LCD (if the LCD shows it), if the LCD is a standard type, you could sniff the infos that the uC sends to it, and use them. That would require a lot of digital programming skills. But I'm not saying that it is possible, but maybe is.
Or, if you set the tempo with your foot on the DD20, you could read that pulses with a uC and traslate them to usefull stuff (just like DD20 does internally). This is doable for sure (for example I added Midi capability to my DD20)

update:
now that I think about it, if I'm not wrong the DD20 also has a led that indicates the delay time.. You could simply take that pulse and traslate it into bpm (but you will need to know the right note division used), again using a uC.

I know this topic has been down for sometime but I thought I may bring some resolution to the topic....
The whole idea comes from the fact that there's a blue LED on DD20 that's constantly blinking in quarter notes regardless of subdivisions. So we can use it to generate continuous tapping for external devices. There's a wonderful electronic component that called solid state relay (or optical relay). It allows isolated switching when current flows through its control pins. So we have to insert this relay into blue LED's circuit and the pulse driving the LED will also drive a relay. Relay closes and opens contacts just like momentary type tap tempo switch.