Transition from PIC 16F to PIC 18F

MIDIbox SID
1

Hi everyone!

I’m working on an unfinished project I got from a really nice person from Germany. He gave me lots of ol’ school stuff (DIN, DOUT…) and a CORE v2 with a PIC16F + SID module v2 with 6581.

 

I managed to debug it and test it without a LCD (it was fried), and I was able to play the basic SID patch with a midi keyboard.

 

But I wanted to get more out of it so I bought a 18F452, uploaded the bootloader with my PIC programmer, made the mods (crystal, connection to pin22 changed to pin 28), installed the chip, connected the two boards following this schematic, connected a 2x16 LCD, tested voltages, and then uploaded MIOS1.9.

 

Everything worked fine : CORE communicating in MIOS, LCD working fine.

 

Then I used the testtone (OK), and the interconnection test (OK). I connected a bankstick, and I uploaded the SID 6581 .hex file.

 

Everything went well again.

 

At restart, the bankstick was formated, and I heard the launching gimmick from the SID.

 

But then, nothing more. Just a sort of phantom, very light clicking noise when I play notes on the MIOS keyboard.

Each time I start again, I can hear the gimmick sound, but I’m stuck with it.

I haven’t connected the CS for now (I’ll go for the minimal CS, option A), but I thought I’d get a basic sound even without the CS…

 

I tried to upload the patches through sysex, but it doesn’t seem to work, whereas formating of the bankstick seemed to work.

 

(I also noticed that the 6581 tend to get quite hot in its middle after a few minutes, but maybe that’s normal…)

 

Any suggestions from the SID masters are welcome, I wouldn’t like to make a permanent damage to the SID…

 

Thanks!

2

The 6581 will get hot, thats normal. And the opening sound is a good sign that the SID is working. Chances are its just a patch problem.

 

That said, I’m running my 6581s on a PIC18F4685 using the SID V2 firmware.  This has a default set of patches.  

 

I say all that to say, I would learn towards an issue with the PIC or firmware and less with the rest of the hardware.  Before you go out and grab a new PIC however, move a different patch to the default patch and then try playing.  Or see if you can send a CC command to change the patch. If you get a new tone then everything is fine and an LCD and a minimal control surface should help you change patches

3

Thanks Digineural, I’ll try this right away!

4

It seems that there is a problem with the Bankstick, as I used cc #0 to change to Bank B, and the LCD reads “no bankstick”.

 

Another weird thing though : when I change the value of cc #0 and then go back to initial value, I get normal sound for a few seconds while playing with the MIOS keyboard (it is the extreme fatness of the initial patch).

But then it cuts, and no more sound. And a weird high pitched hiss (that was gone during the few seconds the SID worked as normal).

It can last 2 seconds, up to 10 seconds. If I play a continuous single note, it seems to last longer. 

Really weird.

Also : how hot is normal for a 6581 ? Is “hot like you can keep your finger on it but you’d rather not” OK ?

Thanks!

 

{EDIT} I changed the 24LC256 on the bankstick, and I formatted normally, like the first one. There was a repeated note for each patch during the formatting process, so no doubt that the SID works.

But I cannot seem to put the patches on the bankstick using the sysex tool from MIOS…

5

… Anyone on how to upload the patches to the bankstick ?..

6

UP?..

7

Are you still trying to run the v2 firmware on a PIC18F452?

This can’t work, because this chip has only 1/3 of the memory of a PIC18F4685, which means that a majority of the firmware is missing (I’m surprised that anything is working… :wink:

 

So: once you are using a PIC18F4685, patches can be uploaded with the SysEx Librarian which is integrated into MIOS Studio.

 

Best Regards, Thorsten.