• Please review our updated Terms and Rules here

ATX64/Pulse64 Rom chip question.

B

brostenen

Experienced Member
Joined
Jul 4, 2017
Messages
61
Location
Denmark, Northern Jutland.
Hi all.
I have bought a couple of those C64 clones from UNI64. More accurate the ATX64 board and then the Pulse64 board. However there are the question of the rom chip, that I have no idea of how to solve. In the manual of the ATX64, it is stated that all three roms have to be in an 28C256 chip on the following locations....


0000-2000 Basic
2000-3FFF Kernel
7000-7FFF Chars

I have searched wide and far on the web, in order to find a rom-chip like this, however I have not found anything. If it is a question of a custom BIN file that can be burned to an eprom, then wre to find this file?


Thanks in advance
 
Hi,
The 28C256 is an EEPROM, seems to be available pretty easily at places like digi-key:
https://www.digikey.com/en/products/detail/microchip-technology/AT28C256-15PU/1008506

Sounds like you just need to make a binary file that contains the contents of the specified C64 ROMs at those locations. You can do this in a hex editor, basically open each of the rom .bin files and place them at the specified addresses. The space between 0x4000-0x6FFF would just be empty, probably doesn't matter what you put there but most likely 0x00.
Basically cut and paste the basic rom to address 0x0000, then immediately after do the same for the kernal rom, then add zeros until 0x6FFF and then the contents of the char rom.
Was the question more about how to do this or where to find those roms?
 
bitfixer said:
Hi,
The 28C256 is an EEPROM, seems to be available pretty easily at places like digi-key:
https://www.digikey.com/en/products/detail/microchip-technology/AT28C256-15PU/1008506

Sounds like you just need to make a binary file that contains the contents of the specified C64 ROMs at those locations. You can do this in a hex editor, basically open each of the rom .bin files and place them at the specified addresses. The space between 0x4000-0x6FFF would just be empty, probably doesn't matter what you put there but most likely 0x00.
Basically cut and paste the basic rom to address 0x0000, then immediately after do the same for the kernal rom, then add zeros until 0x6FFF and then the contents of the char rom.
Was the question more about how to do this or where to find those roms?
Click to expand...

Thanks for the quick reply.

My problem is that I have no idea on how to make the BIN file, though I am in contact with a person who have the tools to burn the file.
The question was actually both on how to make the BIN file, as well as if there is a place to download a ready made file.

I will see if I can make such file. Yet I must confess that I have never dived into this specific topic of vintage computing before.
So I am kind of in the dark as of now.
 
Got it. The simplest tool to use would probably be a hex editor, HxD is a good one on Windows, Hex Fiend on Mac. You need to locate the individual C64 ROMs in question, open each file individually in the hex editor, and then copy and paste into a new window in the editor.
Basically get the BASIC rom, copy, then paste into your new window. This means that rom is at the start of a new file, and thus maps to start at 0000, through 0x1FFF.
Then get the Kernal ROM, paste at the end of the contents in your new window, this means the kernal is mapped to 0x2000 and will extend to 0x3FFF.
Then in your editor you want to write a bunch of 00 characters, until your address is up to 0x7000. Just copy a chunk of them and repeat. The address listed in the editor may be in decimal, so that would be 28672. That just means you have that many bytes in the new file at this point.
Then copy/paste the last ROM. Save this file as ROM.BIN or something. That file should be exactly 32768 bytes long. If not, the number of zeros pasted is probably off by one.
This resulting file would be directly writeable by an EEPROM programmer.
Hope this helps, let me know if you have more questions.
 
bitfixer said:
Got it. The simplest tool to use would probably be a hex editor, HxD is a good one on Windows, Hex Fiend on Mac. You need to locate the individual C64 ROMs in question, open each file individually in the hex editor, and then copy and paste into a new window in the editor.
Basically get the BASIC rom, copy, then paste into your new window. This means that rom is at the start of a new file, and thus maps to start at 0000, through 0x1FFF.
Then get the Kernal ROM, paste at the end of the contents in your new window, this means the kernal is mapped to 0x2000 and will extend to 0x3FFF.
Then in your editor you want to write a bunch of 00 characters, until your address is up to 0x7000. Just copy a chunk of them and repeat. The address listed in the editor may be in decimal, so that would be 28672. That just means you have that many bytes in the new file at this point.
Then copy/paste the last ROM. Save this file as ROM.BIN or something. That file should be exactly 32768 bytes long. If not, the number of zeros pasted is probably off by one.
This resulting file would be directly writeable by an EEPROM programmer.
Hope this helps, let me know if you have more questions.
Click to expand...

Thanks. :)
I will see if I can find a good and basic hex editor for Linux, and then follow this aproach. :)
 
On linux you could also do this on the command line, i.e
Code: 
dd < /dev/zero bs=12288 count=1 > empty.bin
cat basic.bin kernal.bin empty.bin chars.bin > rom_image.bin
 
You must log in or register to reply here.
Back
Top