Thanks again Wilba.
that all sounds like great advice!
I will do some more tests this evening and get back to you.
Thanks again,
Alex
Less CORE PCB’s, more PICs.
It’s too bad you have had such a hard time uploading, I’d recommend just getting a new pic, and checking your boards… Smash’s are pretty straightforward, I even swapped some caps around on the SID and it’s like I have “ghetto bass” as they call it.
If you are getting the upload request sysex string once, that is good, if it is repeating, that isn’t bad. If you can use MIOSstudio, that makes everything a lot easier… When you upload code, the core is supposed to respond with a checksum, MIOSstudio will verify that checksum and continue.
I dont think it’d be a computer or interface problem (by the way @ up, I uploaded code with an old m-audio device)
Hi HL-SDK,
it’s good to know you’ve manage to upload MIOS using an M-Audio interface. I’ve tried several different ones now, so I’d be really surprised if ALL of them don’t work- must be a PCB/PIC-related issue I think.
I’ve been using MIOS Studio (though for some unknown reason, it won’t work on one of my computers).
It does make things nice and simple, though MIDI-OX gives you more options in terms of setting buffers etc.
I’ll give the little test Wilba recommended another go and see what happens.
I guess the reason I’ve been concentrating on trying dofferent MIDI interfaces and setups at the computer end is that I know more about computers than about electronics! To my untrained eye, the soldering on both PCBs looks fine, but it does look as if there are major problems with at least one of the boards and possibly with the PIC as well. The loopback test will help a lot, I hope.
I suspect the fact that I’ve soldered a few MIDI-related boards in the past that have worked fine 1st time (including some quite cool ones from http://www.highlyliquid.com) has given me a false confidence in my soldering abilities 
Maybe it’s the jumpers on the bottom of the v.3 board… was never completely happy with those…
Right, time to break out the soldering-iron again.
Cheers guys,
Alex
OK, I’ve done the loopback test again, as you suggested Wilba.
Both boards ‘pass’ ie if I send MIOS to the out port, I get exactly the same back at the in port, byte-for-byte. Works in MIOS Studio running under Windows and MacOS, incidentally. I haven’t tested all my MIDI interfaces, but it’s probably not worth doing that now.
So, this means that the the PIC should be able to send and receive MIDI on both boards. Something must be different on the 2 boards though, as I get different error messages. I’m using the same PIC on both boards (forgot to order the PIC from Mike when I put in my order for the v.3 boards, though I have one on the way now). The PIC I have currently is the one that came with the SmashTV kit, and is indeed a PIC18F452, with the bootstrap loader already burnt (I don’t have my own PIC burner).
I built the SmashTV kit entirely from the parts provided, though the other board has a replacement optocoupler which I swapped-out on the off-chance that this might help.
Should I wait for my new PIC to arrive, or are there any other tests I could run? I know the PIC is getting power on both boards. I also get a MIDI output from both boards, and when connected, the LCD works on both, though unreliably, as mentioned in previous posts. I ran the loopback test without the LCD or SID modules connected, by the way, as you suggested.
Thanks again,
Alex
Incidentally, HL-SDK, I like the sound of Ghetto Bass’ 
well if the loopback works, then I guess it has to be the PIC not working properly… either its oscillator/clock is bad somehow or there’s still the chance that the MIDI interface is at fault.
You’ve basically validated the electronics and wiring between PC and PIC… so now it’s just a matter of either end being the fault (although there’s still the change the PCB is at fault)… At this point, (if it was me) I would be trying that PIC in another known-working Core, and trying a known-working PIC in the non-working PCB… this would identify if it was the PIC or the PCB.
Hi Wilba,
thanks for getting back to me again.
I have another PIC on the way from Germany (should hopefully be delivered in the next few days), so I can test that when it arrives. Unfortunately, what I don’t have is a known-working core PCB. Is there anything I can do to test the oscillator/clock on both boards while I wait for the new PIC to arrive? I only have a basic multimeter, being a relative newbie, though I may be able to get access to an oscilloscope at work.
Re. the MIDI interface, I’ve tried several different MIDI interfaces, on several different computers, and I’ve used MIOS studio, MIDI-OX and Sysex Librarian under MacOS X and Windows, so I’m reluctant to believe that none of my interfaces work…
Thanks again,
Alex
well in theory, if you receive the upload request, this sort of proves that the PIC is running and its UART is set up with the right baud rate, etc. since your computer is receiving it fine. There are configuration bits burned into the PIC so the bootloader and MIOS know whether to use standard MIDI baud rate or the alternative serial port baud rate (and more recently, whether to use IIC_MIDI instead).
What I’m confused about is the frame errors and overrun errors… because I think they imply the PIC is receiving at a different baud rate, or with serious bit errors… but your loopback test proves that at least your MIDI interface sends and receives at the same baud rate without errors… hmmm…
I was theorizing about the oscillator… it’s definiately working or you would not receive upload requests at all.
If I were in your shoes with what you have at hand, I would get one of those experimenter boards, in Australia they’re called “Wish boards” (brand name), I guess they’re also called breadboards… they’re white or cream coloured plastic boards with lots of holes in them that you can insert components into without soldering… then I’d make up a Core board with that… I guess this assumes you have enough spare bits lying around…
What you’d end up creating is the bare minimum to get the Core sending and receiving MIDI, which is basically the 5v supply (7805+caps), the crystal and its two caps, the optocoupler bit and the MIDI sockets… and also 100 ohm resistor tying the reset pin to 5v.
OK, it’s a big ask I guess, if you’re not really into electronics or have the extra bits lying around… but if you’re keen to keep up the hobby and make more things, one of these experimenter boards are very cool to have around, you can easily whip something up to test circuit ideas etc. or even just test LEDs or chips…
Back to the issue of the two boards giving different error messages…
Can you swap the optocouplers and see if the error messages stay the same? i.e. if they swap their error messages also…
I know both PCBs passed the loopback test but it might be useful to know if one optocoupler produces errors the other doesn’t.
Hi Wilba,
I picked up a book on beginner electronics a while back, which I keep meaning to make a start on. One of the reasons I haven’t got round to it yet is that all the exercises require a breadboard! Looks like I’ll have to pick one up. They’re not too expensive, I don’t think, and as you say, they’ll come in handy for all sorts of things.
I don’t currently have duplicates of most of the Core board parts (except for the replacement optocoupler I bought), and some of the resistors, maybe. I do have a 5V ‘wallwart’ PSU though, so maybe I don’t need the 7805 (I removed it from both boards because I was initially using the Optimised PSU and original C64). I’d just need to pick up the caps, oscillator + another PIC w/ bootloader. I have another PIC on the way anyway, so if that doesn’t work in either of my current boards, then I may do the breadboard thing. It would be useful to me as a exercise in translating circuit-diagrams into working physical circuits, anyway (you wouldn’t believe how long it took me to put together a working Optimised PSU based on the diagram).
So, am I right in thinking that if the crystal oscillator wasn’t working correctly, the PIC wouldn’t work at all? It’s definitely sending out the upload request string on both boards. It won’t do much else, but it seems to do that fine…
I’ll swap the optocouplers around when I get home and see what I can find out from that and get back to you.
Incidentally, could the issue with my LCD module be related somehow? I know I did connect the LCD incorrectly the 1st time, so I wouldn’t be surprised if I had damaged it, but it may be related to my MIOS upload issues.
Cheers,
Alex
One little word has made me a very happy man!
That little word is glowing on the screen of my pink LCD screen right now..
That little word is:
“Ready”
Weeeeeeeeeeeeeeee 
I swapped over the optocouplers from the two boards. Board #2 still doesn’t work, so it’s either a soldering/component error (not unlikely), or the optocoupler that came with the SmashTV kit is dodgy.
I must admit I found Mike’s kit a little more challenging to construct than the SmashTV one, which is nicely labelled with all components. I’ll recheck all the component values and solder joints again. It could well be I used the wrong resistor or capacitor somewhere in there…
As for the SmashTV kit, after I’d swapped the optocoupler, and put my one PIC back in the socket, the MIOS upload worked the first time I tried it! I guess it must have been a dodgy optocoupler, or maybe just something that removing and reseating both chips fixed. I still can’t understand why the loopback test worked perfectly, but the main thing is I’ve finally managed to get MIOS on that bloody chip! I’m a little scared to try uploading the SID application now though, just in case it’s stopped working again…
Fingers crossed.
Thanks again for all your help Wilba (and everyone else who responded to my plea for help). I’m so happy to be able to move on to the next stage, at least with one of my two boards!
Lets see if I can get SID on there now, wish me luck, guys!
Thanks again!
Alex
congrats mate, glad you got it working!
Good to hear!
Just to recap: you swapped the two optocouplers around, so now the SmashTV PCB (which previously was giving the frame errors and overrun errors) is WORKING? and the Mike’s PCB which was only sending out upload requests is unchanged?
You really should swap the optocoupler back and prove it’s really the optocoupler (you seemed to think reseating the optocoupler was the cause, highly doubtful, but make sure anyway). Put a big tick on the “good” optocoupler!!!
So Mike’S PCB is broken in another way. It’s hard to know how, since you had the “good” optocoupler in there, and the PIC which was eventually proved to be good, and the loopback test passed… since it’s sending upload requests, the PIC is powered and oscillator is good… maybe it is continually resetting? Check power supply I guess… and all solder joints around the optocoupler, TX, RX pins…
The best news is, you now have a working PIC + Core PCB + MIDI connection. This makes debugging the second Core a lot easier… because you know what the bug CAN’T be…
Now that you have MIOS on the PIC, when you put it in the other PCB, you should only get ONE upload request, and you have 2 secs to upload a new MIOS, or you can upload an application at any time. What this means is when you put that PIC in the other PCB, if you keep getting upload requests you know the PIC is resetting itself for some reason… I guess you could also try the LCD in the other PCB and check if it’s “READY” also…
Hi Wilba,
Just to recap: you swapped the two optocouplers around, so now the SmashTV PCB (which previously was giving the frame errors and overrun errors) is WORKING? and the Mike’s PCB which was only sending out upload requests is unchanged?
That’s about the size of it. The 2nd kit still just sends out upload requests, but the second one seems now to work fine. I’ve managed to upload MIOS, the SID application and the SID Interconnection test app so far. I have another spare optocoupler now, so I will try that in the Mike’s board, though I don’t expect it to make any difference. I’ll also try swapping the optocouplers back again, as you suggest, just to see.
I’ve been using 2 different PSUs (a 5v ‘wallwart’ one and an Optimised PSU/C64 brick one), but both seem to work with the SmashTV board.
Now that you have MIOS on the PIC, when you put it in the other PCB, you should only get ONE upload request, and you have 2 secs to upload a new MIOS, or you can upload an application at any time. What this means is when you put that PIC in the other PCB, if you keep getting upload requests you know the PIC is resetting itself for some reason… I guess you could also try the LCD in the other PCB and check if it’s “READY” also…
I’ll definitely try this, though I’m getting increasingly nervous about removing and reinserting the PIC chip- those pins are so delicate!
I’m at work at the moment, but as soon as I get home, I’ll try the tests you suggest, and let you know what I find out. I may even pop home at lunchtime and give it a try…
Thanks once again for all your help and encouragement,
Alex
Just a small remark: You dont have to push the PIC all down into the socket, as long as all pins connect. It will make it easier to uninstall from the socket, if you just place it lightly - atleast as long as you´re troubleshooting.
I really hope you will have some succes soon, im glad its not me havent your problems.
/carsten
another tip: put the PIC in a spare IC socket (assuming you use the cheap ones, not the expensive machine pin ones)… this makes it easier to insert and remove from the PCB as well as preventing the pins being bent. An old trick from when I was constantly moving PICs between PCB and burner.
You should also get an IC removal tool… just a cheap one that looks like a really wide pair of tweezers… I can’t believe I went so long without one, cursing every time I had to pull an IC out… if only to give the SID chip some respect, get one ;D
Just a small remark: You dont have to push the PIC all down into the socket, as long as all pins connect. It will make it easier to uninstall from the socket, if you just place it lightly - atleast as long as you´re troubleshooting.
Ah, that’s good advice Carsten. I didn’t realise that.
another tip: put the PIC in a spare IC socket (assuming you use the cheap ones, not the expensive machine pin ones)… this makes it easier to insert and remove from the PCB as well as preventing the pins being bent. An old trick from when I was constantly moving PICs between PCB and burner.
So you mean put the IC in a socket, then put that socket into the socket soldered to the board?
Genius…
I’ll add a spare socket to my little (but growing) list.
You should also get an IC removal too
I will try to track down one of these. Sounds very very useful. I’ve been using a screwdriver pushed underneath the IC, but it’s quite hard to lever the chip out without bending the pins.
…if only to give the SID chip some respect
I always treat my SIDs with respect and wear the ceremonial gloves, hat and cloak when handling it
Alex
Just got the first sound out of one of my SID boards!!!
I’m very happy
Still loads of work to do- need to get the Mike’s Core up-and-running. I put a new optocoupler in it and put the PIC (now with MIOS installed) back in the socket. I still can’t upload anything to it, but I now get MIDI Frame Errors, rather than nothing except Unexpected Upload Requests. It’s not rebooting all the time, anyway, so it’s definitely progress! I’ll recheck solder joints and component values again later.
The working SID board is the one I got with the kit From Mike, which I just put together this evening. For symmetry’s sake though, I’d like to get the Mike’s MIDIShop Core, and SmashTV SID working too, of course. Unfortunately, that means desoldering and removing all the pins from the SID socket I managed to break while testing voltages a while back. I’m going to need to invest in some desoldering braid, I think, because my desoldering pump isn’t doing the job.
I’m so glad I’ve managed to get a sound from it at last!!!
Alex
I wonder have you been able to fix that board from Mike’s shop? I’m having exactly same problems now and don’t know what to do. Please help if you have solution.
Thanks
I wonder have you been able to fix that board from Mike’s shop? I’m having exactly same problems now and don’t know what to do. Please help if you have solution.
Thanks
Hiya,
it’s a while since I did any MIDIBox stuff I’m afraid (got sidetracked into other things).
I honestly can’t remember if I did get the Mike’s MIDIShop boards working, but I suspect not. I know I did manage to burn out one of my PICs by sending 14v instead of 5v through it, and that the working SID synth setup I have so far consists of 2 Smash TV boards (no control-surface yet, though I was only planning a ‘Step-A’ to start with) . Unfortunately I don’t have time at the moment to troubleshoot the Mike’s boards, but I’ll have another look next month when I have a bit more spare time.
Sorry I can’t be more help right now, and good luck with it!
Cheers,
Alex