Denial

Hi guys,

Does anyone know exactly how to convert prg images of VIC-20 carts into bin files to be burned to eproms? I have some PCB's for DIY Vic20 carts and would like to burn the 27c64 with up to 8k cart images for testing.

PRG files just have the load as the first word (two bytes). Just remove them to covert to a binary file.

srowe wrote: ↑Sat Dec 21, 2019 12:02 pm PRG files just have the load as the first word (two bytes). Just remove them to covert to a binary file.

Hi srowe,

I am not a real expert of hex editing so you mean that with my HEX editor I need to set the first two bytes to FF or delete them?

Delete them, the file size should be a round binary number, 8192, 4096 etc.

Ok srowe thanks a lot

the 8k cart is working good
I edited the prg and deleted the first 2 bytes. That did the trick.

Now my question is how to handle the two separate prg's for 16k carts (6000 and a000 hex)?
I have deleted the first 2 bytes of each then I assume I should concatenate the two but in which order? a000 first then 6000 or the other way around?

You can't just concatenate them, there's a 'hole' between them. You'll need two separate EPROMs, unless you add some decode logic to map accesses to BLK3 and BLK5 to consecutive addresses.

srowe wrote: ↑Mon Dec 23, 2019 7:20 am You can't just concatenate them, there's a 'hole' between them. You'll need two separate EPROMs, unless you add some decode logic to map accesses to BLK3 and BLK5 to consecutive addresses.

Hi srowe,

yes the 27c128 eprom is to be used with the pcb in picture. It is the project available here on Denial and it uses a 74LS00 for the decoding. My question then is to know in which order the two files need to be concatenated or if there is something else to do.
By default the pcb has the L block set to 3 and the H block set to 5.

OK, if you look carefully you can see there's a bridge between pads for BLK3 in Block_L and one on the BLK5 pads in Block_H. So you want to create a single image from the one that resides at $6000 followed by the the one at $A000.
You'll also have to populate the socket, I'm guessing it needs a 74LS00 but without a schematic I can't tell for sure.

srowe wrote: ↑Mon Dec 23, 2019 8:05 am OK, if you look carefully you can see there's a bridge between pads for BLK3 in Block_L and one on the BLK5 pads in Block_H. So you want to create a single image from the one that resides at $6000 followed by the the one at $A000.
You'll also have to populate the socket, I'm guessing it needs a 74LS00 but without a schematic I can't tell for sure.

Yes by default BLK 3 on block_L and BLK 5 on block_H are bridged. So I have to concatenate $6000 and $A000 in this order then. Yes the decoder is a 74LS00, I have it but did not put it on the socket yet

Hi srowe,

It is a fail unfortunately. I concatenated 6000 and a000 then another file with a000 first and 6000. I burned the 27c128 and tested both files but none is working. The VIC20 will boot to the prompt each time. The 74LS00 is fine and tested with the programmer.
Those 6000 and a000 files are in prg format so I delete each time the first 2 bytes then concatenate. No luck
For info the game I was testing is Robotron.

Try dumping the contents of the memory block using a BASIC program.

srowe wrote: ↑Mon Dec 23, 2019 10:05 am Try dumping the contents of the memory block using a BASIC program.

Sorted out finally . I was testing with apparently a corrupted 16k game image files (Robotron from zimmers). Tested with another game and it fired up