PIC based CV Quantizer (now with variable modes)

Peake · Posted: Mon Jun 07, 2010 11:39 am Post subject:

OH, this is extremely welcome...I especially like the voltage addressing of scale type. Don't forget a scale based upon the harmonic series (Yamaha had this as an option for the modwheel for use in horn sounds). Also, an "octave" scale can be nice for transpositions etc. A scale which goes to the fifth, the octave above, the octave above plus a fifth, etc.

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

Uh oh ... I don't have any of the 16F684 myself, wanting to blow this code into one of my PICs, so I've been comparing the datasheets for the 16F684 side-by-side with the 16F689, of which I'd bought 5 of. I were understanding everything in reading each of the 2 PIC's pin functions, until I came to the CCP for the 16F684 and now I'm quite lost. Sad

See, the 16F689 has a fair bit more power for the CCP/P1A than the '684. Converting / setting up the '689 to work in the same way as the '684 has me stuck.

Could anyone out there who has more experience than I with PICs, lend a hand by chance?

I'm trying to teach myself from the ground up, in PIC programming and have basically so far gone only through the first 5 or 6 lessons included with all of the literature for the PICkit 3 and it's companion 18F45K20 demo board. The 'tutorial' though, is assuming that you know many, many things already - so it's been a bit bumpy so far, in comprehending everything - even though I've understand the Basic programming language more and more since 1982 and I have a very ROUGH idea, on a little bit of study in programming in C and C++. (I'm also extremely comfortable with electronics design / building / etc. My biggest trouble so far has been in trying to find a nice 'walk through' in teaching yourself how to work with PICs. MPLab's literature isn't as friendly, as I'd hoped.)

Thanks for any possibilities. Surprised

Junk Rhythm · Joined: Jan 07, 2008 Posts: 81 Location: San Francisco, CA

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

Junk Rhythm · Joined: Jan 07, 2008 Posts: 81 Location: San Francisco, CA

Boogdish · Joined: Sep 21, 2009 Posts: 122 Location: Bloomington, IN

Junk Rhythm · Joined: Jan 07, 2008 Posts: 81 Location: San Francisco, CA

Rykhaard · Joined: Sep 02, 2007 Posts: 1290 Location: Canada

Boogdish · Joined: Sep 21, 2009 Posts: 122 Location: Bloomington, IN

I'm designing a PCB for this project. It'll have an optional onboard voltage regulator for those that don't use a +5V rail and seperate grounds for digital and analog. I've also ported the code for use with a 12F683, so the board should be pretty small (I'm not done, but I'm shooting for 3/4" x 2 1/2").

My goal with this board is that in addition to people being able to build this circuit as a stand alone module it can also serve as a daughter board adding a quantize function to other modules like sequencers, LFOs, etc. I'll be adding a bypass mode for this purpose as well.

Peake · Posted: Sat Jul 24, 2010 1:45 pm Post subject:

Congratulations, superb! I'm excited about this project.

emdot_ambient · Joined: Nov 22, 2009 Posts: 667 Location: Frederick, MD

I would certainly buy some DIY quantizers......if they came with the PIC. I've got enough things to learn just building projects without adding programming chips into it!

a100user · Joined: Oct 28, 2003 Posts: 158 Location: UK

I share emdot_ambient's view, a PIC with a PCB would be very cool.

robotfunk · Joined: Jun 22, 2009 Posts: 20 Location: Netherlands

The first time programming anything, and you start with assembly? I admire your guts.

MickeyDelp · Posted: Thu Oct 28, 2010 3:52 pm Post subject:

Great project Boogdish! Very elegant solution.

You might want to put a zener diode on the input to protect the PIC since control voltages can be higher than 5V. Which raises the question: is a 5V range enough? Would it be better to put a voltage divider on the input and doubler on the output so that it had a 10V range?

P.S. We're practically neighbors! I think Lampasas is about 90 minutes from Austin. It would be great if you could come to our monthly Handmade Music Austin workshops.

fonik · Posted: Fri Jun 17, 2011 4:43 pm Post subject:

HELP, i need some help. am i drunk or dumb or both? i dunno.

a couple of weeks ago i burned the rev1 code to a 16F684 using MPLab and the PICKit2. yesterday i built the circuit on veroboard and it worked from the start. so far so good.

then i wanted to burn the varimod code. and guess what? i forgot how to do it...

this is how i did it, but it did not work at all:
i renamed the *.txt file to *.asm
i opened MPLab and started the project manager
i selected the correct device, the MPLab suite assembler compiler, and loaded the varimod asm file (now in the MPLab source folder)
i then selected release mode
then i did a right click on the asm file, selecting "build"
it stated a build success

then i tried to burn directly to the PIC from MPLab: no error message, but the module did not work

then i tried to export the build to a hex file in order to burn it manually using just the PICKit2 programmer. when reading the hex file all fields where 3FFF, so i think that something is completely wrong (suspicious)...

i am puzzled. i did it before and now i cannot get it to work - all the software/pic/programmer stuff is driving me crazy Laughing

so if anybody has any hints... i feel so dumb tonight.

blue hell · Posted: Fri Jun 17, 2011 5:05 pm Post subject:

I usually make a project with the asm file in it as the only file, just like you seem to have done; be sure to also sure to select your programmer as the current programmer and to not have a debugger set; then I hit the compile button from the toolbar, which will then compile and program ... all 3fff is completely wrong indeed - that means nothing got compiled.

fonik · Posted: Sat Jun 18, 2011 7:42 am Post subject:

so i am doing it right in general!? the devil is in the detail... and the awkward thing is that i programmed the PIC successfully weeks ago Laughing

- there must be a little thing that i miss now though. i wished there was someone knowledgable sitting right beside of me when working with PICs.

blue hell · Posted: Sat Jun 18, 2011 7:50 am Post subject:

Can imagine .. hard to see from here .. don't want to start MPLAB here now, being in the middle of a radio session - can try that tomorrow though.

Boogdish · Joined: Sep 21, 2009 Posts: 122 Location: Bloomington, IN

If all you need to do is compile to a hex file from an asm file, open MPLAB without starting a project. Go to File ---> Open, select the asm file, and then go to Project -----> Quickbuild. This should compile the hex file in the folder containing the asm file.

fonik · Posted: Sat Jun 18, 2011 11:31 am Post subject:

guess what? that's exactly what i did right after jan's post. and it worked. i think i must have overdone it when creating a project and all that stuff.
anyways, thanks for taking care, boys!

kingconga42 · Joined: Jul 24, 2009 Posts: 13 Location: CT, USA

Anyone thinking of making PCBs and programmed PICs?

andrewF · Posted: Sun Aug 21, 2011 2:33 am Post subject: Re: PCBs?

kingconga42 · Joined: Jul 24, 2009 Posts: 13 Location: CT, USA

thanks!

LektroiD · Posted: Fri Sep 23, 2011 8:52 am Post subject:

Could someone explain the whole AGND / GND thing to me? I'm not getting the explanation in the documentation at all... I assume it is like this...

with 15V source, use (+15V & AGND)
with 5V source, use (+5V & GND)

is that right?

I'm now wondering which GND/AGND I use to ground the sockets, or is this intended for banana jacks?

If someone could make a simple wiring diagram that would be great, as I'm not translating this from text at all.

Thanks in advance Smile

emdot_ambient · Joined: Nov 22, 2009 Posts: 667 Location: Frederick, MD

My understanding is that the circuit was designed for a +15V power supply, but can run on anything from +9V to +15V.

The circuit also needs a +5V source but that can either come from a separate power supply, OR it can be derived from the +15V supply using the power regulator.

So, if you're using a separate +5V supply, then you SHOULD NOT use the power regulator, and the 0V from the +5V supply can be used for the GND input, and the 0V from your +15V supply to the AGND input, thus keeping the digital and analog grounds separate.

If you're NOT using a separate +5V supply, then you MUST USE the power regulator and you can run both GND and AGND from the same ground. But I think you do have to use both (as in just connect them together).

I'm using a 4-pin MOTM power distribution system (+15V, -15V, and 2 0V wires with no +5V supply). So with the power cable I'm making, I'm connecting one of the 0V lines from the PSU going to GND and the other to AGND. The -15V I'm actually using on a daughter board that's limiting the input of the CV input to +5V.