well i finally got my fv-1 based pedal finished and off the annoying breadboard....thanks to the guys on here for their help, much appreciated guys.
uses the internal fv-1 sounds and 2 extra eeproms, for 24 sounds... 8) 8) 8)
now i can play around with patches/banks without removing eeproms etc just plug in my pickit and voila'....programme on the fly. yay.....
i made the pcb so i could either install an fv-1 smd, or use a pre-soldered fv-1 breakout board.
https://www.youtube.com/watch?v=EiJzAPnQYzA&t=325s
https://deadastronaut.wixsite.com/effects
(https://i.postimg.cc/VSwPJBNk/20210213-161429.jpg) (https://postimg.cc/VSwPJBNk)
(https://i.postimg.cc/tY1jw4fp/20210213-161456.jpg) (https://postimg.cc/tY1jw4fp)
(https://i.postimg.cc/BXd00G9D/20210213-161550.jpg) (https://postimg.cc/BXd00G9D)
(https://i.postimg.cc/jDPrqkt1/20210213-161710.jpg) (https://postimg.cc/jDPrqkt1)
(https://i.postimg.cc/vgHRzYfR/20210213-162402.jpg) (https://postimg.cc/vgHRzYfR)
(https://i.postimg.cc/S2ZB1Bfn/20210213-162956.jpg) (https://postimg.cc/S2ZB1Bfn)
(https://i.postimg.cc/DWckLJWd/20210213-163254.jpg) (https://postimg.cc/DWckLJWd)
(https://i.postimg.cc/hhZn2d22/20210213-170028.jpg) (https://postimg.cc/hhZn2d22)
Outstanding!
thanks mark.... a big thanks to the guys on here who know what they are doing ,
im just a noob with this digital lark, but it sure is fun... 8)
well done! wow
Very nice! I especially like the "programming slot"! :icon_biggrin:
How do you know which EEPROM you're programming? Is it whichever one is selected on the front panel somehow?
hi tom, cheers, yeah left toggle is bank A....right bank B. same as on pcb.
and centre is internal.. 8)
Pin 14 on the FV1 (SCK) is a serial clock output from the FV1 (presumably used by the FV1 after a power up or reset).
Does your PickIt connect directly to that pin and drive it with its own clock signal, and if so, does the FV1 mind having that pin treated as if it is an input ?
I connect the PICKit 2 directly to SCK & SDA on my FV-1 board without incident. I guess the FV-1 tri states that pin unless it is doing a read (which it only does at power up or when you change the patch selector lines).
I see IC3 is running off 9V supply. I don't see any measures in place to stop the inputs (pin1 and 2) of the FV1 being limited to the range specified in the Absolute Maximum Ratings on the FV1 datasheet.
Datasheet says voltage to pins 1,2 should be limited to between -0.5 and 3.8V (assuming you are on 3.3V supply).
I am guessing pins1 and 2 are normally sitting there biased at around the halfway level (say 1.65V).
So if a large input signal to the circuit causes the IC3A input buffer to go close to its rails, you'll have a pk-pk signal voltage close to 8V coming out of IC3A. Won't that cause the input voltage limit to pins 1 and 2 to be exceeded?
If so, it might be an idea to add back-to-back protection diodes in there somewhere. I don't know if exceeding the max input voltage at those pins just leads to clipping in the A/D section of the FV1 or to actual damage of the chip.
The alternative to protection diodes is to just have all the analogue chips running off 3.3V too (which is a redesign as I don't think TL072 works well on such low supply).
EDIT: One way to do it can be seen on Engineer's Thumb schematic. At circuit input there are back-to-back red LEDs. You can do similar. Use Green LEDs as they'll have a larger voltage drop. You can put that sort of protection off board at the circuit input.
But that won't give protection at startup if IC3A output goes high for some reason. Best place to put the protection diodes is somewhere after C19 in your schematic. One 1N4148 going to 0V and another going to 3.3V.
DrAlx raises a good point. What exactly happens depends on the chip in question of course, and I don't know the answer for the Fv-1 specifically, but it's unlikely to be a fantastic outcome.
I had this same problem with the Druid DigiDelay pedal. On the dsPIC, if the input goes outside the uP's power rails, it crashes the chip. This isn't fatal, but it reboots almost instantly and forgets the tempo it was running at before. Quite annoying. The solution was (as suggested here) to stick some diodes on the input to limit the signal.
Sensational!!
Looks like I picked the wrong week to give up building Rob's projects...
(https://pbs.twimg.com/media/ClrH3OeWIAAXyTC?format=jpg&name=900x900)
Hmmm... Seems I have an FV-1 going spare... :icon_rolleyes: :icon_biggrin:
Quote from: DrAlx on February 15, 2021, 04:49:10 PM
after C19 in your schematic. One 1N4148 going to 0V and another going to 3.3V.
cheers alex, interesting, i think i get what your saying. but likely not ha ha.. ;D
so a 1n4148 anode points to 3.3v and the other 1n4148 cathode points to ground? and they join between at the junction between the C19, and R6. ? is that correct?.
Nice one! Really nice!
Quote from: bluebunny on February 16, 2021, 04:18:38 AM
Looks like I picked the wrong week to give up building Rob's projects...
(https://pbs.twimg.com/media/ClrH3OeWIAAXyTC?format=jpg&name=900x900)
Shirley you can't be serious!
Quote from: Fancy Lime on February 16, 2021, 05:36:21 AM
Shirley you can't be serious!
You feed me lines like that and expect nothing to happen??
Well, I
am serious. And don't call me Shirley.
Looks like the foot is on the other hand now, Mr. Kramer!
Anyway, you started it!
Rob - have you considered offering some pre-programmed eeproms on your site?
Quote from: deadastronaut on February 16, 2021, 04:44:14 AM
Quote from: DrAlx on February 15, 2021, 04:49:10 PM
after C19 in your schematic. One 1N4148 going to 0V and another going to 3.3V.
cheers alex, interesting, i think i get what your saying. but likely not ha ha.. ;D
so a 1n4148 anode points to 3.3v and the other 1n4148 cathode points to ground? and they join between at the junction between the C19, and R6. ? is that correct?.
Diode clamps like in the link below. My mistake Rob saying 1N4148 diodes would do it. Those will not give enough protection as they have forward voltage drop that is too large. You need Schottky diodes like in the link below as they have forward voltage drop under 0.5V.
https://i.stack.imgur.com/Rx33R.png
EDIT: Those clamps should work on either side of R6. I would put them on the FV1 side right at the ADC input (pins 1 and 2).
^ cool, cheers alex, so a couple of 1n5817's should be ok then...
: marc, hmmmm....maybe, i'll have to see how i go, i'm not a coder by any means, im just using spincad, then exporting a hex file to programme the epproms with pickit2.
but yeah, you never know...
Hi Deadastro- The Fv-24 is looking really nice and sounds very nice as well. Congrats on getting it all built and working the way you wanted.
Regards the clamping diodes on the inputs of the FV-1 for p-p protection, I used to use BAT42 Schottky diodes but later pedal designs I ended up just not putting them in on newer designs as they are not really needed.
Really nice Rob. Do I need one? No. Will I build one anyway? Most likely :)
Quote from: Ice-9 on February 16, 2021, 12:50:58 PM
Regards the clamping diodes on the inputs of the FV-1 for p-p protection, I used to use BAT42 Schottky diodes but later pedal designs I ended up just not putting them in on newer designs as they are not really needed.
The FV-1 reference schematic shows a 1k resistor in series with the inputs. This may well serve to limit the potential of "large" input signals to destroy or lock up the chip. It's just a guess. I know it's also part of some LPF at the input.
Quote from: Digital Larry on February 16, 2021, 01:30:19 PM
Quote from: Ice-9 on February 16, 2021, 12:50:58 PM
Regards the clamping diodes on the inputs of the FV-1 for p-p protection, I used to use BAT42 Schottky diodes but later pedal designs I ended up just not putting them in on newer designs as they are not really needed.
The FV-1 reference schematic shows a 1k resistor in series with the inputs. This may well serve to limit the potential of "large" input signals to destroy or lock up the chip. It's just a guess. I know it's also part of some LPF at the input.
Yeah, this makes sense too. The VCDO chip that I did used a 4K7 resistor in series like this to protect the ADC inputs. It limits the current that can flow through the *internal* protection diodes to a safe level, and thereby negates the need for *external* diodes. And (like in the FV-1 schematic) if you've got a resistor there, you might as well add a cap to ground and get some lowpass filtering to help remove any out-of-band noise.
Quote from: stallik on February 16, 2021, 01:08:38 PM
Really nice Rob. Do I need one? No. Will I build one anyway? Most likely :)
^ this <sigh>
Don't sigh! I think of FV-1 projects as "solder once, tweak endlessly in code". It's the final frontier and all that. :icon_mrgreen:
Fantastic. I love those ambient sounds from around 7:30 onward and again around 9:35. So good.
It would be fabulous to have trails when switching presets.
Quote from: Digital Larry on February 16, 2021, 05:57:58 PM
Don't sigh! I think of FV-1 projects as "solder once, tweak endlessly in code". It's the final frontier and all that. :icon_mrgreen:
I was afraid of that... Software is my day job, so coding isn't necessarily my idea of fun. Having said that, I downloaded SpinCAD yesterday and had it up and running on Linux in no time... Must. Resist. . . .
^ cool , yeah its great that you can use spincad with just a wave file....
excellent for previewing/ testing patches..
i use a guitar wave with staccato and long chordy stuff...
Quote from: jonny.reckless on February 17, 2021, 03:32:40 AM
It would be fabulous to have trails when switching presets.
Can't be done with a single FV-1.
Yup. Decided I definitely won't be going down this rabbit hole.
.
.
.
No hurry with my order Rob ::)
^ aha...its a good rabbit hole though.... :icon_mrgreen:
Will pop in post ... 8)
That was quick Rob, lovely looking board
FV-1 finally arrived a few days ago. Looking forward to finally play with this
Cool, youll love it, i built 2 , the pedal, and put the other in a rack... :icon_cool:
Look forward to your build.. 8)
Very nice Rob
You should look into adding the 4049 clock module into your design. It adds more control to the effects. I added one on my FV project and a switch to be able to switch between the crystal and 4049 clock.
So, I've had this board for a year now and only just started populating it :icon_redface: Have a few parts on order but am looking forward to going down this rabbit hole in the new year.
With zero live experience but a little time playing with SpinCad, I have a question. This board is mono using the left output from the FV-1. Would it be possible to use the right output and the relevant circuitry after it and (perhaps using dual pots) create a stereo version usable with a dual amp setup? As I'm not using the FV-1 daughter board, there should be enough room to mount another board above the chip and still keep the same size enclosure.
Or, are patches which use such stereo effects going to be too limited by the processing power of the chip?
Quote from: stallik on November 29, 2022, 04:06:24 PM
So, I've had this board for a year now and only just started populating it :icon_redface: Have a few parts on order but am looking forward to going down this rabbit hole in the new year.
With zero live experience but a little time playing with SpinCad, I have a question. This board is mono using the left output from the FV-1. Would it be possible to use the right output and the relevant circuitry after it and (perhaps using dual pots) create a stereo version usable with a dual amp setup? As I'm not using the FV-1 daughter board, there should be enough room to mount another board above the chip and still keep the same size enclosure.
Or, are patches which use such stereo effects going to be too limited by the processing power of the chip?
depends on what you're doing. the max delay time is 1second (when using the normal crystal). so for stereo you only get 500ms of delay, and it takes twice as much code (since you need to write each channel individually). with only 128 instructions per program, you can run out of program space pretty quick too. a true stereo pitch shifter should be doable. a true stereo reverb will be tough to fit but doable. ultimately i don't think it's worth it, which is the reason nearly all fv1 designs are mono (despite the stereo in/outs).
what bugs me is hardly any of the mono designs i see use the stereo i/o pins for differential i/o. i guess pedals are always going to be noisy haha
Congratulations and respects !
Quote from: stallik on November 29, 2022, 04:06:24 PM
So, I've had this board for a year now and only just started populating it :icon_redface: Have a few parts on order but am looking forward to going down this rabbit hole in the new year.
With zero live experience but a little time playing with SpinCad, I have a question. This board is mono using the left output from the FV-1. Would it be possible to use the right output and the relevant circuitry after it and (perhaps using dual pots) create a stereo version usable with a dual amp setup? As I'm not using the FV-1 daughter board, there should be enough room to mount another board above the chip and still keep the same size enclosure.
Or, are patches which use such stereo effects going to be too limited by the processing power of the chip?
You can also put in a feedback loop, perhaps with some clipping diodes to get some crazy effects :D
Thanks for the replies guys.
Seems to me that if I were to introduce a daughter board for the right channel of the fv1, I wouldn't necessarily have to use it on every patch. So far, I've only played with SpinCAD but some of the stereo patches I've put together sound promising though I've no idea how they would fare in real life.
I think this rabbit hole is going to be fun - it's going to be too cold in the workshop for woodworking till spring