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CBM 8032 software mod 40 column screen too small

terryfi

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Jul 5, 2022
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Hello everyone,

I recently fixed a broken 8032 PET by replacing its CRTC with Rockwell R6545-1P.
This PET is 80 columns by default so I decided to use cbm4032 any hz.prg to soft mod it to 40 columns.

The 40 columns work but screen is too small, is this expected?
I understand if pixel size doesn't change 40 column would take half of width but can't we get the pixel size being adjusted proportionally so we have a full-screen 40 column mode?
Does doing the hardware mod, changing jumper connections on motherboard, fix this issue?
 

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daver2

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>>> The 40 columns work but screen is too small, is this expected?

IMHO - yes.

>>> Does doing the hardware mod, changing jumper connections on motherboard, fix this issue?

Yes.

However, you can have 40 or 80 columns - not both. There is a little third-party 'switch board' to permit changing from 40 to 80 columns 'on the fly'. But you may also require a modified EDIT ROM.

Dave
 

Eudimorphodon

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Long and short of it, you can’t fix it in software. The program you’re using is changing what it can, IE, how many characters it displays per scanline. The CRTC has no control of the actual pixel generation hardware and therefore cannot change the dot clock. (Machines with CRTCs that do support different resolutions have to implement the soft switches for this on their own.)
 

terryfi

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Last edited:

daver2

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It has to be a universal or a universal 2 to have the 40/80 jumper block - but I might be wrong on this count...

Dave
 

MikeS

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It has to be a universal or a universal 2 to have the 40/80 jumper block - but I might be wrong on this count...

Dave
No, you're quite right!

There are three board versions:
8032089 - this is the one for which the switcher was designed.
8032080 - the switcher can be made to work with this one with a minor adjustment.
8032030 - incompatible with the switcher since there is no jumper block.

See the enhanced switcher here for more info:

And the board layout for the 8032089:

m
 
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