Wilba
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Posts posted by Wilba
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Steven: No, Bunnings. :P
Scratches won't be a problem - Lazertran decal will be baked on, toner side down. Apparently this leaves a fairly tough coating on the panel, protecting the toner.
I wouldn't make a whole case out of 0.5mm aluminium sheet... but this is just the front panel and spans only 5 inches top to bottom, and doesn't support anything except itself. I made mockups with paper and taped them to the C-64 case... they can withstand finger pressure (being taut like a drum skin)... so I'm fairly confidant the panel won't bend through normal use. Even so, I might just add some support in the centre just in case.
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First up, thanks for the feedback.
NorthernLightX: You could upload yours to the midibox portal site.
TK: Thanks for the tips.
0.5mm aluminium sheet is widely available here (in Australia)... it's available in electronics stores for front panels on plastic boxes, but I got 300x900mm for $10 at a hardware store.
I don't see how it can bend during drilling... I'm going to use a drill press.
There's enough overlap around the panel's edge with the C-64 case to stop it bending when attached. I plan to glue it to the case, and the encoders, switches and LEDs poke through it and are mounted on a board that's attached to the C-64 case. Thus there is nothing mounted on the panel itself. This thin panel lets me mount encoders, switches and LEDs on a single board, the buttons poke through 3.5mm, the entire encoder shaft is exposed. (Scale diagram follows)
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Hi all,
I just want some feedback on this design before I proceed... for some reason I feel it's missing something... I know the space in the top right is a bit empty... any suggestions welcome.
(In no way am I suggesting TK's layout needed improvement... I just wanted to be creative)
A hi-res version can be found here:
http://www.avishowtech.com/midibox/photos/MB6581_frontpanel_design_v1_large.png
Design variations from TK's original:
- Slightly taller frontpanel (~5mm)
- The "Assign" encoders are (sort of) aligned with the display.
- Added "Curve Assign" button/LEDs
- Added extra LED to "Envelope Ctrl" group (so encoder can control "Curve" parameter)
- Added "Mod Matrix Ctrl" button/LEDs to support switching of mod matrix mode
(ie. for AOUT outputs or a second mod-matrix mode)
Note: These additions use the unused DIN/DOUT pins.
Construction details:
- Thin aluminium (0.5mm) frontpanel with Lazertran decal artwork.
(Aluminium is simulated in picture.)
- Case is original (brown) C-64 case, painted black.
- Knobs are black plastic (not as spiky as pictured), slightly tapered, 14mm high.
- LEDs are all frosted clear (aka milky white) LEDs, mostly blue.
- Buttons are like TK's - ALPS model SKHHDH (17mm stem height).
- Display is Noritake character VFD (custom parallel interface, will require some driver coding).
TODO:
- only using "Curve" in envelope alternate mode - what to do with the others??
- fix up top right corner artwork
Wilba
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Can I assume that the AOUT module schematic http://www.ucapps.de/mbhp/mbhp_aout.pdf is final and order some MAX525 and MAX6007B samples?
How do you get the +12v/-12v supply?
Can you publish a schematic (or at least chips I should bundle with my Maxim order) for getting the -12V DC supply from the MB SID supply (C64 PSU or 15v DC transformer)?
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In difference to the original AOUT schematic the module has to be connected to pin RC.0, RC.1 and RC.2 (J6 of the core module)
I think TK meant pins RC.0, RC.1 and RC.3, since RC.2 is already used as an optional 1MHz clock for the SID chip.
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Wow...
a special button combination which switches the LED matrix of the control surface between common and AOUT matrix --- I will never change my own panel anymore, therefore this solutionWell if you're never changing the panel, there's no need for me to add any buttons/LEDs/encoders since they'll never get used in any official SID release. I'll post a design concept soon for some expert feedback ;-)
Thanks TK,
Wilba
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Since I'm in the long process of making a MIDIbox SID step C (and redesigning the front panel), I've thought about accomodating some future extensions now - some that I might add and some that are still floating around in TK's head ;-)
I'm anticipating some kind of analog output (to control an external filter, volume control, panning, etc.).
Is this going to involve one MAX525 per core, so that each core (in a multi-SID setup) can modulate up to four analog outputs? Should I therefore add another four rows to the modulation matrix?
Or is this overkill and I should only add one row and use CORE:J5 to drive my own quick'n'dirty 8-bit parallel DAC?
I know this is FAR ahead for me (still in panel design/construction phase) but I'd like to have my panel design accomodate the extensions...
Suggestions welcome.
Wilba
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Great work... wish I could see more detail... all that red stuff around the LFO/oscillator waveform LEDs looks cool...
What's the stuff on the far left (switch, knobs, LEDs?)
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Great work... wish I could see more detail... all that red stuff around the LFO/oscillator waveform LEDs looks cool...
What's the stuff on the far left (switch, knobs, LEDs?)
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eBay auction - Nice panel full of faders and knobs which could be good for a conversion to a MIDIbox.
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=2371221670&category=41479
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I also have thought about reverse engineering the SID station patches to get some inspiration for new sounds (and try to get some of the Giraya sounds I heard on their website!)
Since I don't have the specs on some things (ie. how fast the LFOs oscillate), I can't write a converter just yet - also some things aren't convertable without some clever wavetable useage (eg. interleaving an envelope and an LFO - aka. "lace").
But my curiosity has got the better of me, so I will write a tool to view the SIDStation patches in human-readable format. At least then we can see what they do and manually make a patch to emulate it with the MB SID. (This of course will be multiplexed along with MB SID construction and other MB programming tasks ;-) )
Regards,
Wilba
P.S. We need to locate and interrogate a SIDstation owner.
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I don't think there's a need to get a hotter soldering iron just for pots. You should be able to solder pots with a 15W iron. There's nothing special about the leads, they're just often much thicker than other components. Pots are pretty heat tolerant. The converse is not true though: you can fry components with too hot an iron.
My miscellaneous soldering advice:
Get one with a small tip.
Use very thin solder.
Cut component lead close to PCB, bend a little to hold in place.
Heat component lead and add solder to the joint. Do it quickly. If it isn't done in three seconds, leave it to cool before trying again.
Don't carry solder on the iron to the joint!
Exceptions: tinning wires, tacking one lead in place while you solder other lead properly.
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I don't think there's a need to get a hotter soldering iron just for pots. You should be able to solder pots with a 15W iron. There's nothing special about the leads, they're just often much thicker than other components. Pots are pretty heat tolerant. The converse is not true though: you can fry components with too hot an iron.
My miscellaneous soldering advice:
Get one with a small tip.
Use very thin solder.
Cut component lead close to PCB, bend a little to hold in place.
Heat component lead and add solder to the joint. Do it quickly. If it isn't done in three seconds, leave it to cool before trying again.
Don't carry solder on the iron to the joint!
Exceptions: tinning wires, tacking one lead in place while you solder other lead properly.
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This is how I got my JDM programmer (for PIC16F84s) going (scroll down to section with orange background):
http://www.talkingelectronics.com/FreeProjects/MultiChipPgmr/MultiChipPgmr-P3.html
You don't need to change serial port settings in Device Manager. JDM doesn't work like that - it's not doing RS232 communications.
Also: just because the hardware worked a year ago is no guarantee there's not a problem now. Maybe there's a broken track or bad solder joint. Use the JDM troubleshooting guide to verify programming voltages and IC-Prog configuration.
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This is how I got my JDM programmer (for PIC16F84s) going (scroll down to section with orange background):
http://www.talkingelectronics.com/FreeProjects/MultiChipPgmr/MultiChipPgmr-P3.html
You don't need to change serial port settings in Device Manager. JDM doesn't work like that - it's not doing RS232 communications.
Also: just because the hardware worked a year ago is no guarantee there's not a problem now. Maybe there's a broken track or bad solder joint. Use the JDM troubleshooting guide to verify programming voltages and IC-Prog configuration.
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I have a question regarding the power supply for 4x CORE and 4x SID modules. I'm not using a C64 power supply, just a transformer with 15v DC output.
I plan to model it on the diagram in mbhp_4xsid_c64_psu_optimized.pdf. 15v DC into a 7812 regulator, the 12v going to all SID modules. 15v DC into a 7809, the 9v into a 7805, the 5v powering the SID and CORE modules in two separate 5v/GND supply lines.
What I don't understand in that diagram is why the VS pins of the J11 ports on the CORE modules are connected... there's already connected VS pins in the J2 ports.
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I got it working, finally... ;D
To cut an already long story short:
I isolated the reset clock line - using a wire direct from PIC to shift register's reset clock pins. Problem persisted. BUT... I was lucky to notice some audio difference when I moved the logic probe near the reset pins.
More debugging... I discovered that touching this wire (ie. grounding it with my body) made it WORK. I start to think my ground rails are at fault... then realise my fundamental mistake (aka. major F.U.)
My power supply is currently on a breadboard, and consists of 15v DC from transformer going into a 12v regulator and a 9v regulator. The 12v output goes to the SID. The 9v output goes to a 5v regulator, this 5v output goes to the SID.
I was connecting the 9v output of my power supply to J1 on the core. That's the setup that DOESN'T WORK.
When I connect the 5v output of my power supply to J2, then that WORKS.
By powering the core with the 9v at J1, it's going through the bridge rectifier before it gets to the 5v regulator, and that means it's going through diodes, which means that the ground of the core is actually 0.7v higher than the ground of the power supply and the SID module, which (I assume) means PIC outputs will be shifted up by 0.7v as well.
Why that should matter, why the reset clock goes intermittant and yet the other shift register inputs aren't affected... no idea. I don't think it matters... I've got a working SID synth... hooray! ;D
Regards,
Wilba
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(Wilba checks Meeshka's profile)
Meeshka: You live in Melbourne, Australia. Unbelievable coincidence - so do I! ;) I've sent my email address in a private message, perhaps I can help you out.
Wilba
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I can only suggest my fix for low voltages: try using a 9.1v zener diode instead of an 8.7v (or an 8.2v substitute). That should increase programming voltage. The 9.1v zener is the only thing different in my JDM and what made it work!
Make sure you're testing MCLR voltage against the VSS pin, not the GND of the RS232 socket.
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The mystery is almost solved! (This post is mostly to sate TK's curiosity!)
SID player works because it doesn't do any BankStick or DIN/DOUT handling, thus there's no clocking of J4:SC/J8:SC/J9:SC (shared serial clock) other than the SID register updates, and thus there's no "garbage" getting shifted into the shift registers.
MIDIbox SID app has BankStick and DIN/DOUT handling, thus garbage (zeroes?) gets shifted into the shift registers in between SID register updates, but it shouldn't be LATCHED. In my case it does get latched, therefore the shift register's RCLK pins must be going from low to high.
If I ground SID module's J2:RC, I still get garbage latched to the shift registers. If I force J2:RC high, no garbage gets latched.
Maybe there's a spike getting into the RCLK tracks on my SID module (latching occurs on the low-to-high edge transition of the RC line). It's too fast for my logic probe to see, but it has to be there.
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You can download and use a 30-day "trial" version of the latest Protel. Slightly unintuitive at first, but it grows on you. You do have to create a few custom components and footprints (ie. for capacitors, upright-standing resistors, etc.) but the end result is professional.
My tips for beginners:
* learn about net labels and power ports (ie. ground symbols, +5v symbol etc) - these simplify schematics and you can set preferred track widths per "net".
* use vias and top layer tracks to represent bridges (if you're doing a single-sided PCB)
* use the Inspector window to change properties
* always route manually!
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Unfortunately, capacitors have very small labels - it should have a three digit code on it (sometimes among other numbers on both sides, to confuse matters).
Here's the basics:
471 = 47 plus 1 zero = 470pF
102 = 10 plus 2 zeros = 1000 pF = 1 nF
104 = 10 plus 4 zeros = 100,000 pF = 100 nF
334 = 33 plus 4 zeros = 330,000 pF = 330 nF
NB: capacitor colour/size/shape doesn't indicate capacitance value, although it does relate to the type of capacitor - ie. ceramics are usually terracotta colour, flat discs.
From experience, the small signal diodes 1N4148 have always been a reddy orange colour and slightly transparent, and smaller than a standard resistor. They should be marked with the code. Power diodes are black and fatter, and zener diodes are a mixed bag of colours (yellow, blue, etc.) They all have the cathode marked (the pointy end of the diode symbol).
Hope this helps.
Regards,
Wilba
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Did memory peeking, MIDI note stacks all ok.
The problem has something to do with the reset pin on the SID chip.
When using SID player, this pin is low when nothing is playing, then goes high while the song is being played, then back to low when it's done.
Whe using SID synth app, it goes high while in an explicit call to SID_TUNE_Play1 (in sid_init.inc right after the "reset" of the SID)... then it goes low most of the time and occasionally goes high when a note is played or when a patch has a wavetable. The tunes don't play when it reads the bankstick.
I added a 10k pullup to the reset pin (as per original schematic/PCB) which did nothing.
I changed code to always set the reset pin high and it didn't appear to change anything.
I hardwired the reset pin high (disconnect shift register completely). Success! MIDI notes play!
I'm not fully understanding what the real problem is, but I guess I'm getting closer. It's basically because the reset line is brought low whenever the shift registers aren't being used... this all seems to suggest it IS a hardware problem after all. TK, what should I expect the reset pin state to be most of the time?
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I'm just about to add some debugging output - was planning to write to LCD but sending MIDI is a better idea, thanks.
I tried adding a BankStick last night which didn't fix the problem. I turned on the "Link to Slaves" (I don't have slaves yet) and I get an echo of the note on/off events. I definitely get a change of state (ie. noise increase) with a note on event with some patches (like ones with WT) as if the WT gets started up, and this stays noisy even after the note off.
My SID PCB is slightly different (missing pull-up resistor on reset pin, which you said was OK). Since the SID file player works, I don't think I had a hardware problem.
No one is more curious than I am!
Lucky for me I'm a coder by trade or I'd be LOST trying to debug this problem! (I think I'll have to write a SID troubleshooting guide after this!)
Merry Christmas to all!
Regards, Wilba
cheap alternative screen
in Design Concepts
Posted
More info in this thread:
http://www.skippari.net/phpBB2/viewtopic.php?t=474
I might try this on a Nokia 8210 LCD I salvaged (after replacing the screen assembly).