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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Sun Jun 24, 2012 9:51 pm Post subject:
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Hi Gang,
Okay, the votes are in! The tally is:
1 vote for the menu structure already posted (2 if you include me)
and
0 votes opposed.
So, I guess we stick with the menu sequence I proposed. That's an overwhelming majority.
Today was spent filling in the setup menus with writes to the registers. Everything is going well and I'm still under 3000 bytes (barely). Also, I was able to get the register read routine working after a bit of diddling. I'm actually holding back a bit; it was a long day of debugging, but it turned out that problem was me, not the circuit. Anyway, it all works now.
I do have all of the menu setup stuff done now and can report that the output is dead on with respect to frequency. I'm quite stunned. When I punch in 100 Hz, that's exactly what I read on the counter, and likewise for all other values. On the other hand, the match to the equally tempered scale is dicey above 1 kHz in places.
Thanks, THeff, for your update. It's good to know someone is actually trying this out. The hardware and software work amazingly well, don't you think? I had originally thought that gremlins would constantly haunt us, but actually the AY chip cooperates with the Picaxe pretty well so far. To your ears, how does the tuning sound when you try your test MIDI program? Thanks again for actually trying this stuff out. I wish we could get others involved to spread the labor out.
Thomas Henry |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Sun Jun 24, 2012 10:03 pm Post subject:
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This fell lower on my priority stack when it didn't seem like firmware development would be visible, but I just completed another project that's been sucking up time (which also frees up the second big breadboard if I need it) so I should have time to actually test along side THeff starting this week. I need to catch up with the circuit mods and additions (output for audio and such) and I expect to be ready to go tomorrow night. |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Mon Jun 25, 2012 6:35 pm Post subject:
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Hiya THeff,
Have you had any luck making the noise generator do its thing? I haven't and am rapidly running out of ideas. I can get the three tones without any trouble, but the noise is dormant so far.
Does it work for you?
Thanks,
Thomas Henry |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Mon Jun 25, 2012 11:57 pm Post subject:
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Meh.
It's WAY too late for a work night.
I'm having no luck with my picaxe, I'm going to have to tear things down and try simpler things first. My own fault for not starting that way to begin with :/. |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Jun 26, 2012 2:18 pm Post subject:
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If anyone is working with the picaxe from a MAC I would appreciate it if you can PM me. I don't want to hijack this discussion with personal troubleshooting (though I will probably report back what finally fixes it). I've ripped the picaxe down to the bare minimum, I'm getting "Hello..." messages and can read the firmware, and I've tried all kinds of variations but still no luck getting the download to go. I'm about to the point of abandoning the sparkfun USB adapter in favor of either 1) the arduino usb/serial which can be used for picaxes with a couple additions or 2) a totally different serial solution. |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Jun 26, 2012 2:45 pm Post subject:
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Thanks Thomas
Searching hasn't gotten me over the hump, and I'm waiting for them to approve me for posting access on their forum. That definitely is on the list as well.... |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Jun 26, 2012 8:11 pm Post subject:
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Thank you, that is very useful information.
Yes, I am using the 22k resistor on the breadboard side.
Since the sparkfun adapter is SMD, are you doing the termination at the breadboard end of things?
I just finished making a "real" serial cable, DB9 -> stereo jack, and I'm about to go try and figure out where I stashed my USB->RS232 adapter from years ago (just had it out this week though, was shuffling stuff). If I can't get that method to work, then I will come back to this sparkfun beastie and try to use your suggestions.
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Tue Jun 26, 2012 8:22 pm Post subject:
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Hi elmegil,
I put the resistors on the breadboard not the Sparkfun adapter. You don't want to use the 22k because it is there to level shift the PC serial RS232 from +12v down to +5V and shunt the -12V at the PIC. The FTDI chip on the Sparkfun board is already at a 5V TTL level.
I believe the 100 ohm/10k resistors are there to prevent ringing on the long cables.
-THeff |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Jun 26, 2012 8:28 pm Post subject:
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Great, thank you for that clarification.
The good news: my hand built DB9 cable works great as is, so I think I'm not going to mess with success . I have a blinking light, it's late-ish, I was up too late last night, and I have an early day tomorrow, but I'm optimistic that I will be in business soon.
I will probably at some point test the sparkfun with those changes just to be able to close the loop for anyone following along, but I want to hear sounds first |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Tue Jun 26, 2012 8:46 pm Post subject:
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elmegil,
I was looking at the axe027 document again and they say you can leave the 22K resistor there even when using the USB cable. It also says you can reduce it to 1k if you want, but they recommend leaving this resistor there just in case you should happen to use a PC serial cable at some point. 22k seems like a lot of series resistance if you are connecting TTL to TTL.
The 22k is needed for sure is your are using the PC serial port.
Glad you got it working!
-THeff |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Wed Jun 27, 2012 3:01 pm Post subject:
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Hi THeff,
No joy with the noise yet. I put it aside for the nonce and decided to see how the EG performs.
I'm not thrilled. Attached is a test program you can try. I takes us back to a single tone A, responds to MIDI, but now imposes an envelope with instant attack and a one second release.
See what you think. I could hear the 16 steps of the envelope; in fact it's hard to miss them on my rig.
How's it sound to you?
Thomas Henry |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Wed Jun 27, 2012 3:21 pm Post subject:
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Hi again,
I suppose I should mention that when I tried a USB to COM adapter (four bucks from Amazon!) it worked like a champ on an XP machine but was quite erratic under Windows Seven. That's when I discovered Revolution Education has their own driver. After installing it, the adapter worked well on both machines. So even if your adapter comes with its own driver (mine did), ignore it and use the one from Rev Ed.
http://www.picaxe.com/Software/Drivers/AXE027-USB-Cable-Driver/
Nowadays, I just keep an old laptop on the bench which has a COM port---a far simpler solution.
Thomas Henry |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Wed Jun 27, 2012 5:02 pm Post subject:
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Hi Thomas,
Looks like you missed the attachment.
That's really weird about the noise. Are you sure you don't have a bad AY chip? I don't see how everything else could work and not the noise.
Is it possible that the noise is coming out of a channel that you are not monitoring? That happened to me when I tried testing the chord program in the beginning and I thought it wasn't working.
-Theff |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Wed Jun 27, 2012 7:27 pm Post subject:
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Hi Thomas,
I have some really bad news. The AY-3-8910 that I have been using has a date code of 1982 and the noise works fine. I just bought four newer chips from BG Micro with a date code of 0426 (2004 I guess) and the noise does NOT work on any of these chips!
The three tone outputs worked on the first 2004 chip that I tested and I assume on the other three but I did not test the tones on those yet.
-THeff |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Wed Jun 27, 2012 7:49 pm Post subject:
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I tested the four new 2004 AY-3-8910 chips and the three tone outputs work fine, just no noise.
I'm sure that BG Micro does not know they bad, because they are not easy to test without a dedicated microcontroller and firmware.
-THeff |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Wed Jun 27, 2012 8:15 pm Post subject:
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Hi THeff,
Well, that is a bummer. I have some more arriving tomorrow and will continue your tests.
But what about that envelope and VCA? Does yours sound as bumpy (like horrible DC feedthrough) as mine?
Thanks for the update,
Thomas Henry |
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Wed Jun 27, 2012 8:23 pm Post subject:
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Hey Thomas,
I haven't done much with the envelope & VCA yet, can you send the test file you mentioned earlier?
-THeff |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Wed Jun 27, 2012 9:07 pm Post subject:
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The bad news: the AY chip I first wired up is dead, Jim.
The good news: I have a spare, and it works.
Of course "works" is qualified with "to blink an LED" because I was starting at the beginning to be sure I had things working, since it didn't work first thing out the gate. Not clear whether my previous wiring job or some other gaffe caused the premature demise, but I will proceed slowly and test each step of the way. And order some more backups.
BTW, both of mine are the 0426 date code, though obviously I haven't tested the noise. |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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THeff
Joined: Sep 01, 2006 Posts: 229 Location: Florida
Audio files: 33
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Posted: Thu Jun 28, 2012 4:51 am Post subject:
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Hey Thomas,
I did try the envelope test this morning and heard the steps of the DAC that you mentioned. I guess it sounds jagged just like the picture of the curves in the datasheet. This was with the older 1982 chip, so I guess it is the nature of the beast, not a defect. Using only 5 bits leaves a lot to be desired.
-THeff |
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Thomas_Henry
Joined: Jul 24, 2009 Posts: 170 Location: N. Mankato, MN
Audio files: 3
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Posted: Thu Jun 28, 2012 2:30 pm Post subject:
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Hi THeff,
I'm starting to have some doubts about this project or at least what it's good for. In particular, I don't think that the envelope (four bits actually) is fine enough to be useable for most music. The thumping, presumably caused by the DC bias line shifting (starts at 0.5V and goes downward) interferes way too much with the tone. My assessment is that the envelope generator is good for nothing and we should phrase this circuit as though it were a VCO, adding the envelope afterwards in the usual analog fashion. It's too bad, for the exponential decay of the envelope is way better than the linear one of SN76477; it really trails off nicely.
My additional chips arrived today. Of the five I now have, only one could produce the noise. And two of them had screwed up IO ports, and one more no Tone A. Age seems to have had an effect on this part.
So, how do you think we should proceed with this project?
Thanks for your input,
Thomas Henry |
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