No output on Core V2 PIC 18F452 Pin RD6

[Atroxis]

Hi guys,

after I had cancelled my dream C64 SID Synthesizer almost two years ago, because I just couldn't get it running, I now got back to this project in will of bringing it to a glorious end. So first of all a big and warm THANK YOU to TK for keeping dreams alive... :)

Now I've had the chance to connect my MB SID to an oscillator and I was able to do some more checking... But I should start at the beginning:

I do have the minimal setup: 1 CORE, 1 SID and the C64 PSU. All soldering and connections triple checked, there's no short circuit, all voltages are correct at the necessary points (9V for my 8580). Unfortunately, there's no output on my SIC, though MIOS Studio has shown all checksums okay after Updating to Bootloader 1.2, MIOS 1.9 and SID Application 1.7303b.

Connecting my 4 x 20 LC display shows me black bars in row 1 and 3, no sign on row 2 and 4.

Okay, back to my osci: seems like I do not have any output on RD6 from my PIC (18F452). And this on three PICs I've tested. Is this normal? Otherwise: what might be the reason for my non-functional LC and my missing SID output? Clock works fine, MIDI exchange PIC - MIOS Studio works fine. And wiring between CORE and SID has definately been checked and checked again and again.

After two years, I finally want to get this project done and would be really happy for any help! ;)

Thanks,

Markus

[Wilba]

RD6 is used for both the LCD and the SID.

Perhaps you can disconnect the LCD and test if RD6 works without the LCD connected... i.e. perhaps there's a short on the LCD or where you soldered the cable to the LCD or even in the cable or connector itself. RD6 is connected to  RW pin of J15 (the LCD port) so check any shorts between that pin and the nearby pins.

[Atroxis]

Hi Wilba,

thanks for the fast reply! The LCD has already been disconnected, there's no shortcut in the pins...

Best,

Markus

[smashtv]

Connecting my 4 x 20 LC display shows me black bars in row 1 and 3, no sign on row 2 and 4.

Keep in mind this will happen even without a PIC in the socket on most LCD modules.

Okay, back to my osci: seems like I do not have any output on RD6 from my PIC (18F452). And this on three PICs I've tested. Is this normal?

No....It sounds like your PICs were programmed using low voltage programming mode, when high voltage mode is required.  (LVP vs. HVP) if you are reading the datasheets. 

Are you using a JDM?  If so you need a pulldown resistor connected to RB5 to invoke HVP mode.

(See http://www.avishowtech.com/mbhp/mbhp_jdmR2.html under "Design Modifications:")

Burning the bootloader in LVP mode allocates port pins to serial ISP that MIOS needs for other things, notably LCD display pins.

Hoping this is the issue, since it's an easy fix.  :)

Best Regards

SmashTV

[Atroxis]

No....It sounds like your PICs were programmed using low voltage programming mode, when high voltage mode is required.  (LVP vs. HVP) if you are reading the datasheets. 

Are you using a JDM?  If so you need a pulldown resistor connected to RB5 to invoke HVP mode.

(See http://www.avishowtech.com/mbhp/mbhp_jdmR2.html under "Design Modifications:")

Burning the bootloader in LVP mode allocates port pins to serial ISP that MIOS needs for other things, notably LCD display pins.

Hoping this is the issue, since it's an easy fix.  :)

Thanks for that hint - might be exactly the reason. I don't have a JDM, but I've burned the pic at my company on an EEPROMer. I have to admit that I was not really sure how it worked, but I found the 18F452 to programm in the software and burning the pic went without any error messages, so I thought it went just fine. Additionally I didn't have any problem with uploading any software via MIOS Studio... Well...

I'll check if there's a way in burning that PIC in HVP at work (I'm not a technician)...

Thanks again,

Markus

[Atroxis]

Hmmm... just in case it won't work at work with that burner - any idea where I can get preburned PICs here in Germany? I'm not sure yet, but it might be worth just buying them functional instead of having the hassle building a JDM... :) Or any Germans here who can burn my 4 PICs for me? For a small fee maybe?

Best,

Markus

[smashtv]

Hmmm... just in case it won' work at work with that burner at work - any idea where I can get preburned PICs here in Germany? I'm not sure yet, but it might be worth just buying them functional instead of having the hassle building a JDM... :) Or any Germans here who can burn my 4 PICs for me? For a small fee maybe?

Mike has them stocked in his shop ready to use, and there are also guys there who will burn it for you no fee (you pay shipping though).

If no one steps up let me know, it's quite cheap to ship just 4 PICs (I'll erase/burn/test no fee if you pay the approximately $3usd return shipping)

Best Regards

SmashTV

[Atroxis]

Hey wow, this is just great! I'll get back on that if I don't find anyone here, thanks a bunch!!!

Best,

Markus

[TK.]

You can also send the PICs to me (Munich/Germany) - this will only cost you the return postage-

Best Regards, Thorsten.

[Atroxis]

You can also send the PICs to me (Munich/Germany) - this will only cost you the return postage-

Thank you so much! I will check the burner at work on monday and try to find out if it supports High Voltage Mode at all. If not, I'd be very happy to send you my PICs for burning them. This is really great... :)

Best,

Markus