Finally I got a boot screen so I wish to share my experience with future builders...
- I do confirm that you can use PAL 6561-101 VIC chip. You need to use a 4.433618 MHz crystal (as as described in the readme.md) AND the PAL Kernal.
For the sake of simplicity, I'm attaching here a zip with the PAL Kernal ROM (both 256k and 512k). It also includes a dual char ROM; you can swap between VIC-20 and C=64 characters generator (I've noticed you can swap it on the fly, without to switch off the computer).
VIC2020 PAL kernal and char ROM.zip
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EEPROMs like ATMEL AT28C256 for Basic + Kernal and ATMEL AT28C64 for char generator work fine. I tried a Thompson 2764A EPROM, but it didn't work for me.
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Due to a different architecture from the original VIC-20, You MUST place the two 65C22 chips (U21 and U22) into their own sockets or the computer will not boot (different from the Commodore computers, from PET to VIC-20, C=64 and so on, where you usually remove those two chips during the debugging operation, since they're not needed for the computer to boot, but can lead to a black screen if bad)
I'm using Rockwell R65C02 and R65C22, and some 74F chips as described in the readme.md
Now I'm going to build the keyboard, I was happy to see the welcome screen after some initial issues, so I decided to resume here some suggestions before to forget what I did.
Finally I got a boot screen so I wish to share my experience with future builders...
For the sake of simplicity, I'm attaching here a zip with the PAL Kernal ROM (both 256k and 512k). It also includes a dual char ROM; you can swap between VIC-20 and C=64 characters generator (I've noticed you can swap it on the fly, without to switch off the computer).
VIC2020 PAL kernal and char ROM.zip
EEPROMs like ATMEL AT28C256 for Basic + Kernal and ATMEL AT28C64 for char generator work fine. I tried a Thompson 2764A EPROM, but it didn't work for me.
Due to a different architecture from the original VIC-20, You MUST place the two 65C22 chips (U21 and U22) into their own sockets or the computer will not boot (different from the Commodore computers, from PET to VIC-20, C=64 and so on, where you usually remove those two chips during the debugging operation, since they're not needed for the computer to boot, but can lead to a black screen if bad)
I'm using Rockwell R65C02 and R65C22, and some 74F chips as described in the readme.md
Now I'm going to build the keyboard, I was happy to see the welcome screen after some initial issues, so I decided to resume here some suggestions before to forget what I did.