bizarre problem with using custom driver and bankstick on midibox sid

Testing/Troubleshooting
1

Hello,

I have a strange problem using a bankstick  and a vfd attached to my core\sid.

When i use mios 1.8, midibox sid 1.7a and a standard 2x40 lcd the bankstick and display works flawlessly.

With the vfd attached and the driver loaded, the bankstick is not recognized, i can only see the same internal patch.

The vfd driver is the one that’s written by seppoman, he’s been very kind in helping me with this.

His display is the same type.

The only changes to the code i made are:

  • a different app_lcd.inc

  • these lines in main.asm, added immediately below USER_Init:

  ;; select LCD type #7 (custom LCD driver, hooks in app_lcd.inc will be used)

        clrf    MIOS_PARAMETER1    ; variable enable pin not provided

        clrf    MIOS_PARAMETER2    ; variable enable pin not provided

        movlw  0x07

        call    MIOS_LCD_TypeSet

With those changes the vfd display itself is working fine.

Today i tried different combinations of code: mios 1.6,1.7,1.8 and sid 1.6

For the sid 1.6 software, i used sid_init.inc, instead of the extra lines in main.asm

I also checked the hardware connections.

To make it worse, i have 2 cores, (made from pcb’s from mike’s shop) and both show the same behaviour.

Needless to say that my mind is in a bit of disarray!

I hope any of you have a good suggestion.

Stefan

2

Hi Stefan,

could it be, that the VFD consumes so much power, that the core supply falls to <5V? This could evtl. explain, why the BankStick cannot be accessed properly.

Which voltage do you read between the various Vs/Vd pins (ground/+5V) when the VFD is connected, and when not…

(Solution for this case: either a seperate 7805 for the VFD, or a stronger PSU)

Best Regards, Thorsten.

3

Hello Thorsten,

I forgot to say that i use the c64 supply.

But i measured all supply pins of the pic and bankstick. They are a bit above 5 volts.

To be sure, i uploaded the standard 1.7a code and made sure i could play sid and that the presets worked.

Then i connected the vfd display and i could still play sid and use presets.

When i upload the modified code, its is like hello vfd and goodbye patches\sid.

So i don’t think it’s the supply.

kind regards,

Stefan

4

so, the hardware seems to be ok, then it must be a problem with the VFD driver. I don’t know Seppoman’s implementation, could it be that it uses register addresses, which are normaly reserved for the MIOS or the MBSID firmware?

Or in other words: which addresses are used by the driver?

Best Regards, Thorsten.

5

Hi Thorsten,

OK, this is where I come in :slight_smile: I´m sending you the driver source code right now.

I think I didn´t define any new variables or use any variables/registers that are not used by the standard CLCD driver, but I don´t have too much programming experience with Assembler, so perhaps you can see something I´m not aware of.

I don´t have a clue what´s the problem here. My own box with the VFD is ripped into pieces at the moment (needed core modules for other projects and it will be redesigned anyway), so I can´t verify if this problem occurs only with newer versions of MIOS or MBSID. The driver definitely worked with MIOS 1.6 and MBSID 1.6 without any BankStick related problems.

Kind regards,

Seppoman

6

alright, I’ve received the source code, but cannot see any dependency between BankStick and the VFD driver - the implementation of the driver is very good and shouldn’t cause problems.

So, I’ve no idea what could go wrong here

Are BankStick accesses the only problem, or is anything else also not working?

Best Regards, Thorsten.