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Looking for a Promenade C-1 expert

phogren

Veteran Member
Joined
Apr 24, 2009
Messages
580
Location
Morro Bay, CA
I've finally made some progress with burning eproms using promos 2.0 on a C-128. I could copy eproms but couldn't get downloaded rom files to work. I somehow remembered way back when someone saying there were two bits at the beginning of a file that had to be added.
Sure enough once I added two bits at the begining of the files, and chopped off the last 2 I was able to be succesful.
WTF is up with that? Is it some sort of petscii ascii thing?
 

RobertB

Veteran Member
Joined
Mar 20, 2006
Messages
816
Location
Visalia, California
Sure enough once I added two bits at the begining of the files, and chopped off the last 2 I was able to be succesful.
WTF is up with that? Is it some sort of petscii ascii thing?
I believe so (or so it was explained to me). If you need more advice, I can direct you to our club member and Promenade C1 expert, Andrew W..

Truly,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
 

sjgray

Experienced Member
Joined
Feb 3, 2009
Messages
467
Location
Markham, Ontario, Canada
I assume you mean two BYTES, not BITs... I'm not a Promenade expert, but commodore's use two bytes at the beginning of some files to indicate it's LOAD ADDRESS. If you are adding them then I guess the software is expecting them to be there in order to load the file. Those two bytes won't actually be burned to the eprom. What I'm confused about is why you would need to remove two bytes at the end. Check the file size. If you are burning a 2716 for example, which is 2K bytes your file should be exactly 2048 bytes plus 2 more for the load address.

Here is a link to the manual on bombjack.org:

http://www.bombjack.org/commodore/hardware/Promenade_Model_C1_Operating_Instructions.pdf

Everything should be explained there.

Steve
 

carlsson

Veteran Member
Joined
Jul 30, 2003
Messages
6,275
Location
Västerås, Sweden
I always considered the load address to be an emulator invention. When it comes to original media, the load address is specified in different ways:

Tapes: First you load some data into the tape buffer (828-1023 on VIC/C64) and that area contains the file name, the load address for the actual file + possible code to be autostarted.

Floppy disks: The first sector of a file contains a link to the next sector, then the load address followed by the file data. I suppose this is from where the PRG format origins, that all 254 data bytes from each sector are used and the first two bytes happen to be the load address. Note that on floppy disks, file names are stored in the directory (track 18 on 5.25") rather than with the actual file data. Load address though is not specified within the directory, just the first sector of the file which makes sense as SEQ, USR, REL etc files don't have the concept of a load address.

Cartridge: Load address is specified by which pins are connected on the cartridge port, a strictly hardware matter.

I suppose in your case the ROM/BIN files are stored on floppy disk as though you just as well could LOAD them and SYS or soft reset the computer to run them, not specifically for use with the EPROM programmer software. If the ROM files instead were stored as SEQ instead of PRG, you wouldn't need a load address. Once the data is on the EPROM, it doesn't know which address in memory it will show up at until it is put in a cartridge or inside the computer where the location of the socket tells which part of the memory map it belongs to.
 
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