Forum FV-1 project

[slacker]

I agree with Taylor what the FV-1 needs is a "killer app" something that will make people sit up and take notice enough to get over their fear of SMD, dislike of digital effects or whatever it is that's stopping them from taking the plunge. The built in effects are nice enough and usable, but apart from the reverbs they aren't going to excite many people here.

Me I'm just building son of Echo Base with mine, but that ain't gonna do it.

[Skruffyhound]

I'm not too surprised by the low level of interest. We don't know how many lurkers there are but out of the 150 people (I'm guessing) that regularly post on the forum, there must be 50 that being newbies are scared off (I would have been a year ago) 50 that can do it for themselves and 50 with diverse interests and a backlog of projects.
I think it's very cool of Mick to take this on, and it's certainly saving me a lot of effort, so I'm just posting my support.

@Taylor, generous to offer your code, thanks.

[Taylor]

I have actually, a couple of times, started to type up some simple FV1 tutorials, but decided I could point my energy towards other DIY stuff since so few people have a way to work with the FV1. So when the project comes out I will work on that some. The Spin site is great, but I'm thinking that a more entry-level tutorial would be helpful. I know I wished there was one when I started playing with the chip!

[octfrank]

Um, Taylor, you went from "what is this thing" to writing kick-a$$ code in a week. I think a tutorial would have slowed you down. 

But, on topic, we sell a number of the SKRM modules to people that use them in their through hole designs. I have no idea why they haven't posted these designs somewhere. Quite a few are reprogramming them with their own code sets and wrapping analog effects around the board.

[Taylor]

That's very kind, but an overstatement! I'm still a hack. However, I do think that the FV1 is really intuitive, which is why I like it so much. I'm still struggling with understanding analog concepts like impedance and basic Ohm's Law stuff, long after successfully programming all kinds of crazy advanced stuff in the FV1. That's not because I'm a genius, just that the FV1 is an awesome tool that makes things really intuitive once you get into it.

I think one of the obstacles to understanding the FV1 is: what is the accumulator? Most of the errors I see in code, and many of my own fumbles, have to do with understanding this basic concept. I hope to help explain that a bit.

[Govmnt_Lacky]

I am very interested in the FV1 but I am a newby as well. Questions I have are:

What do you use to write the code?
What do you use to program the RAM chip OR the FV1?
Do I need a seperate setup to program it? Like a proto board?

I know I would appreciate a tutorial on programming it. I would like to experiment with this chip but I really get nothing from the website.

[chromesphere]

I would love to build something with the FV1, but my electronics knowledge is limited.  If the project was based around "cloning", where little electronics knowledge is need, i would definitely give it a go!  I've wanted to do a DSP project for a while now, but honestly, i just dont know where to start....there doesnt seem to be any noob-friendly projects for DSP...?

Paul

[Taylor]

I am very interested in the FV1 but I am a newby as well. Questions I have are:

What do you use to write the code?

Spin has their own assembler program, SpinASM. Download here. Someone else has written a different program, but it's kind of over my head, so probably not a good start for a beginner.

What do you use to program the RAM chip OR the FV1?
Do I need a seperate setup to program it? Like a proto board?

The FV1 itself isn't programmed, you load your programs onto an EEPROM, which is an 8-pin DIP or SMT IC that's hooked up in-circuit to the FV1. I have the development board, and that's what I use to program my EEPROMs. You can also get standalone programmers, but I'm not sure which ones will work. I have a "Willem" programmer I bought on ebay, which might do the job, haven't tried yet.

So basically, if you have the development board, you just plug it into your computer via USB, then you can either load a single program into it, or you can make a "project" which is a set of 8 programs that you can switch between once you have your hardware built.

You can utilize the programs within a project in different ways:
-you can have 8 different effects, and use a rotary switch to switch between them (in each program, you can have multiple effects happening at once, but you can't have more than one program on at a time - think of a program like a channel on your tv)
-you can have 3 toggle switches to turn on/off three different functions
-you can have a 4-position rotary and one toggle.

So for example, you could have a reverb pedal with 4 main programs (e.g. spring, hall, flangerverb, pitch shifted verb), then a toggle switch to toggle between a bright and dark version of each of those programs. And that's not taking into account the 3 pot inputs.

[Fuzz Aldryn]

If people need a hint what its capable to do: http://www.zcatpedals.com/

[Ice-9]

To be really interested, people need to see what it can do, how it can sound, and preferably be shown a video of Jack White using it in concert. I think they're also probably turned off by the SMD. This and other reasons are why I never decided to offer any of my FV1 designs as PCBs for sale.

I think Mick just needs to do it and then show people all it's capable of. I will post some programs for them to use when it's available.

The effect isn't that far away from being finished, a couple of free nights to sort the loose ends out is all it should take. I think its great that you could post some programs when i have the PCB finalised.

This version is SMD simply as i wanted to contain the whole lot in a 1590bb, but once finalised i will draw up a through hole PCB as well. Also the addons PCB's are to come as well.

[slacker]

You can also get standalone programmers, but I'm not sure which ones will work.

I use a Pickit 2 programmer which you can pick up for about £25 or so. At the minute I program the EEPROM and then plug it into the FV-1 board, but I think you can use it to program the EEPROM in situ, it's something I need to experiment with.

[Ice-9]

Just a little update.

This morning before going to work I populated the PCB with all the components except for the FV-1. ( I wanted to test before soldering the FV-1 chip in) It all worked fine, the buffers and other circuitry had the same levels and tone as in bypass so is not colouring the the sound. When I got in from work tonight I placed the FV-1 chip in and wired in a data pot, but no control pots as yet, I just left those inputs floating as I only wanted to test that all was working. So later I will try and etch a PCB to mount the three control pots on, having these on a pcb cuts down on the wiring to the main FV-1 PCB.

Here are two pics, one close up of the FV-1 PCB fully populated except for the external eeprom. The 8 pin IC at the bottom left if a 3.3v reg (i have lots of these so wanted to use them) I also have a PCB layout that will take a more usual 3 pin reg so depending on what reg anyone wants to fit it will be possible.



Second picture shows the other bits connected. 4 wires to a data pot. The same four connections can be used to connect an add on board which will allow a stomp switch to be used to scroll through the patches and will also have some sort of LED indicator. The other board is one of my jack/bypass boards, this one only has mono output but the main PCB has both outputs working for stereo.

[Ice-9]

The effect is fully working now after having one or two problems.
The first problem was after soldering the FV-1 chip on the pcb in effect mode I had lots of HISS. I tracked it down to the 3.3v line and as I didn't bother to fit any caps on the input and output of the 3.3v regulator decided to put those on before checking anywhere else and that removed all the hiss. So one problem solved.

The second problem isnt fixed yet, I am using my own true bypass PCB as you can see in the pictures above and I have never had any problems before with switch popping but on this FV-1 circuit the popping is huge.

Here is a picture of work so far , I now have the pots, data switch and true bypass wired up.



I'm also thinking of changing some of the design, there are three control pots for the FV-1 chip but the third pot is used to change the level of the effect, ie chorus,flange,tremolo.
How this works is that all the signal passes through the FV-1 chip including the dry, the pot adjusts the mix of dry/effect meaning the dry sound has to pass through the FV-1 also. I think it might be better design to pass the signal from the input buffer directly to the output buffers using a pot to control the mix between dry and effect, so that the dry bypasses the FV-1 if you follow what i mean. This would mean the third FV-1 pot could  be removed or could be used to control a different parameter when programs are written for the external eeprom,.

[earthtonesaudio]

What's the best option for developing on the FV-1 using a Mac?  I know I can install Windows on my machine, but I'd rather avoid that if possible.

[Govmnt_Lacky]

Nice looking work Mick! 

The rotary switch you are using..... Is it a Binary encoder? How are you doing the switching between effects in place of the 3 switch format?

[slacker]

What's the best option for developing on the FV-1 using a Mac?  I know I can install Windows on my machine, but I'd rather avoid that if possible.

If you want to use the Spin development tool I think the only option is to use Windows. I tried to get it running using wine on my Linux machine, which would also be an option for Macs, but unfortunately I couldn't get it to work. I ended up buying a cheap OEM copy of Windows XP and installed that on a virtual machine, which works fine. Then you need a Mac compatible EEPROM burner, I use the Pickit 2 which has a command line tool for Linux and Macs which is all you need to burn chips.

Like Taylor already posted there is a Java based development tool available http://www.andrewkilpatrick.org/?p=elmgen but this doesn't use the Spin assembly language so unless you've already got some programming skills it's probably not a good option as you won't be able to get the support of the existing Spin community.

[slacker]

I think it might be better design to pass the signal from the input buffer directly to the output buffers using a pot to control the mix between dry and effect, so that the dry bypasses the FV-1 if you follow what i mean.

That's what I've been doing and it works fine, it seems a waste to have one of the FV-1's pots tied up doing that job. I'd definitely add it as an option. The PCB looks great by the way.

[wavley]

I'm not too surprised by the low level of interest. We don't know how many lurkers there are but out of the 150 people (I'm guessing) that regularly post on the forum, there must be 50 that being newbies are scared off (I would have been a year ago) 50 that can do it for themselves and 50 with diverse interests and a backlog of projects.
I think it's very cool of Mick to take this on, and it's certainly saving me a lot of effort, so I'm just posting my support.

@Taylor, generous to offer your code, thanks.

Well, I've been following this thread, I fall into the backlog of projects/married category.  I'm very interested in building it, not at all afraid of SMD (I work in the GHz all day long under a microscope, SMD will be refreshing!), but I have very little experience with DSP other than service manual stuff when I was a repair guy, and I am terrible at coding, so I haven't really had anything worthwhile to contribute.

BUT, maybe if I can build this (combined with the Meeblip I just built) then I'll be able to learn enough to have something worthwhile for it's continuing development or next project.

I just wanted to say GREAT WORK GUYS!!

[Ice-9]

Nice looking work Mick!  

The rotary switch you are using..... Is it a Binary encoder? How are you doing the switching between effects in place of the 3 switch format?

The switch is a binary encoder, and the cheapest i could find, if memory serves me correct it was about £1.50 or about $2. Three conections to the 3 pins on the fv-1 that control the switching and a fourth connection to ground is all thats needed. The switch is adjustable upto 16 positions, so all 8 internal and 8 external programs could be accessed from this one switch. I have mine set to 8 positions only.

[Ice-9]

I think it might be better design to pass the signal from the input buffer directly to the output buffers using a pot to control the mix between dry and effect, so that the dry bypasses the FV-1 if you follow what i mean.

That's what I've been doing and it works fine, it seems a waste to have one of the FV-1's pots tied up doing that job. I'd definitely add it as an option. The PCB looks great by the way.

Yeah I think the next revision PCB will have this done as it will be an improvement on the circuit.
First I have to track down this popping when switching the effect on from the footswitch. I will post an up to date schematic as soon as I can with the switching on if anyone can spot something I have overlooked that could be causing the popping I would appreciate that.