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Posted By
MMS
on 2020-11-22
07:21:59
 |  Re: Video Tutorial DIY Eprom For Commodore Plus 4
Thank you for that very detailed review, it is a great help for noobs, like me.
Frankly speaking, because of the complexity of EPROM writing I did not order any tool for it, I preferred to buy it from someone else, who has a practice. I have a Plus/4 probably defective due to an EPROM, but I have only the budget to keep one +4 and one C16 in working condition. Maybe an EPROM burner may help me to revive some of my collection.
So thank you for sharing this package.
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Posted By
Csabo
on 2020-11-22
09:54:40
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Very nice, excellent job putting this together. I'm sure it will be useful for others as well. Thanks for sharing!
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Posted By
C=Owl27
on 2020-11-22
15:18:07
 | Re: Video Tutorial DIY Eprom For Commodore Plus 4
Thank you for the kind comments.
After going through the steps I was surprised how simple it turned out to be. I do not know if there are more particulars about some of the Roms we can use. Headers and stuff.
And I think I narrowed down why Basic 7 Bin isn't burning correctly to the eprom.
It think it is just over 16K. And when I quadrupled it to 64K it actually ended up being 65K. Which is too large to burn to the chip. The other BIN files for basic 7 were 17K in size. Which is why I kept searching for another that says initially it is 16K, but it was windows that rounded off the remaining size.
It says: 16.0 KB (16,384 bytes)
so the 384x4 ended up adding an extra K.
Does anybody have basic7 bin file that is only 16K?
If so then I could burn this correctly to the chip.
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Posted By
Mad
on 2020-11-23
20:40:59
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
OFF: That video is gorgeous!! Great work!
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Posted By
crock
on 2020-11-24
07:11:58
 | Re: Video Tutorial DIY Eprom For Commodore Plus 4
Regarding your issues with BASIC7, where did you get it? Can you post a link and I will look?
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Posted By
MMS
on 2020-11-24
11:05:59
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Yeah, but 16K should be exactly 16384 bytes of data.
I do not see the problem
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Posted By
C=Owl27
on 2020-11-24
17:25:22
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Okay I see that is normal too.
When I quadrupled the 3+1 rom it too says size 64.0 KB (65,536 bytes)
The last number is what got me confused.
Here is a link to the BIN files I have for Basic 7.
https://drive.google.com/file/d/1VXsNqsET4vvcdSq0Y6fZVUaHMkTOrRlg/view?usp=sharing
I hope I can get this working.
The BIN file does load in Vice as a cartridge.
Included in the zip file is a picture of what happens when I place my Basic 7 cartridge into my plus 4. Also included is a bin which is a read from my eprom chip, 27c512. What is on the chip.
Any help would be greatly appreciated. Thank you.
Also I forget which BIN file I used for making the rom.
Maybe I used both of them in separate attempts but I forget right off hand.
Both cartridges I made don't work.
Accept the one that has three other games on it.
Those games work, just not the Basic7.
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Posted By
crock
on 2020-11-24
17:37:04
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
I'm not permissioned for the link by default, have requested access from you.
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Posted By
C=Owl27
on 2020-11-25
03:34:17
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
I'm so very sorry.
It seems to be new feature to drive where there is another private setting.
I changed it.
Also sent you an email.
Thank you for the help.
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Posted By
crock
on 2020-11-25
06:17:36
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
I see your problem now. The BASIC 7 cartridge is designed to run from the C2 cartridge bank, and not C1. If you look at the schematics, the banking logic in the 264 series allows the selection of 4 different sets of ROM's, each of which is split into the Low (8000-BFFF) and High (C000-FFFF) section.
The first set of ROM's is the BASIC and KERNEL, the second is the FUNCTION ROM's in the Plus/4 only (not connected on a C16/116), and the third is where most normal cartridges sit, which includes all the Commodore ones I've seen. The signals that select these cartridges are known as C1 Low, and C1 High, which are mapped to pins 'B' and '6' respectively.
However, there is a little used ability to also have a fourth bank of ROM's on an external cartridge, which is where BASIC 7 expects to be, which is selected by the signals C2 Low and C2 High, pins '7' and '8' on the cartridge port.
Looking at the GitHub page of the OpenC16Cart, the creator has not implemented the signals for C2, so you cannot use this cartridge for BASIC 7 in its current form.
On the plus side, I looked at all the binary images you created and they are all fine, so you did nothing wrong, and the 2 BASIC7 images you included are identical. I also compared the image you burned to the one read back from the EPROM, and that is mostly similar apart from the 2nd and 4th copies of BASIC7 have a different and rather cryptic start up message "YOU CAN FREEZE LIKE A 30 CENTURY MAN" 
Also, you might want to download a Hex Editor tool which makes it much easier to manipulate and compare binary files. I use one called "HexEdit" , but sadly looks like that has been discontinued.
Rob
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Posted By
C=Owl27
on 2020-11-26
00:35:38
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Thank you for the uncovering that valuable information.
Do you know if the Plus4 accommodates that section of data in one of it's sockets?
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Posted By
crock
on 2020-11-26
06:12:15
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Not without making a hardware modification.
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Posted By
Stinaris
on 2020-11-26
06:47:07
 | Re: Video Tutorial DIY Eprom For Commodore Plus 4
Thanks for this post, finally kicked me into buying an EEPROM Programmer to go with me eeprom eraser and eeproms (which I can't find obviously).
It's really easy!
Now I need to learn how to code my own cartridge.
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Posted By
C=Owl27
on 2020-12-01
04:51:50
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
I was wondering if anybody has a breakdown of the Basic 7 cartridge?
I wonder if somebody has already made a PCB that will provide access to the c2.
If somebody has this cartridge could they post some pictures of the PCB?
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Posted By
crock
on 2020-12-01
06:15:53
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
As I referred to above, you can do this by hacking the cartridge PCB, and cutting the low-ROM /OE trace from pin-B (C1 Low) and instead attaching it to pin-7 (C2 Low), but this would mean the PCB would not work for your other cartridge images.
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Posted By
C=Owl27
on 2020-12-01
23:34:20
| Re: Video Tutorial DIY Eprom For Commodore Plus 4
Thank you once again crock for the information.
I have several more boards to mess with.
Here is a tip for those ordering from PCBWay,
5 boards to 10 boards is just one dollar more.
Not sure what it is in Euros, but also must be a deal too.
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