[Coco] VGA Adapter

[Barry Nelson]

> Ron Klein ron at kdomain.org 
> Sun Feb 19 23:00:37 EST 2017
> 
> For those of you that have a Coco Flash unit, has anyone been able to flash
> a cartridge ROM file to the unit using the PRGFLASH program?  I continue to
> get the following error:
> 
> IMPROPER LOAD ADDRESS!  FILE MUST LOAD AT &H4000!
> 
> I have only tried this on 8K or 16K ROM images.
> 
> I'm using a CoCoSDC in SLOT4 of a Tandy MPI with the Coco Flash in SLOT1.
> The MPI selector switch is set for SLOT4.  I have tried this on a Coco 2
> and a Coco 3.
> 
> Thanks
> 
> -Ron
> 
You can not flash a raw ROM image, you must convert the rom image into a .bin file which loads at address &H4000. There are a few ways to do this. One is to prepend the bytes (shown in hex) for a 16k rom
00 40 00 40 00  
in front of the file and append (shown in hex)
ff 00 00 40 00
onto the end. This is best done on a Window, Mac, or Linux pc or using OS-9. When transferring the file to the CoCo you must also make sure the file type is binary. Another would be to write a small program on the CoCo like this:

10 CLEAR 200,&H3FFF:CLS
20 OPEN “D”,1,”YOURFILE”,1:FIELD #1,1 AS F$
30 FOR X=1 TO LOF(1):GET #1,X:CLS:PRINT X:POKE &H3FFF+X,ASC(F$):NEXT X
40 CLOSE #1:SAVEM”ROMBIN.BIN”,&H4000,&H7FFF,&H4000
50 PRINT”DONE! CONVERTED FILE IS NAMED ROMBIN.BIN”

I think I got that right. It will take some time to run. The resulting file will always be 16k, but when you burn it you can enter the original size.