BadCoder Consolation

Atari Jaguar Video-Games Programming and Development

Uploading to BJL Modified Jaguar

First of all make sure that you have a fully working BJL system. I am using an old laptop running DOS and Windows to develop on, and using the DOS loader to upload to the BJL. The normal DOS loader supports both 4-bit and 8-bit file transfers, and understands how to upload .COF files as well as plain binaries. Badcoder will provide .COF files normally as they work on BJL and Alpine.

If you have the most recent version of the BJL ROM fitted to your modified Jaguar then you will have a number of built-in games, stored in ROM, and requiring no loading time, a great advantage I think.

The BJL screen offers both 4 bit and 8 bit upload options, but you do not need to do anything from here as the DOS uploader program can send the transfer type details.

The M68000 registers are shown too, very useful if a program in development crashes as all M68000 exceptions call this screen.

c:\badcoder\> lo usage: loader [-s skipbytes] [-w wiat] [-b baseaddr] [-p lptbase] [-n] [-8] <filename> skipbytes is # byrtes in header to skip. default = 0 baseaddr is addr to upload to. default = 0x00004000 lptbase specifies base addr of LPT port default = 0x378 wait - counter between longs. default = 1 -n => don't send switch-command -8 => use 8Bit transmission <4Bit is default> c:\badcoder\> lo badcode2.cof badcode2.cof is 327367 bytes long COFF-Header found ... start is $4000 transmit-lenght is 327199 </4bit></filename>
Useful tip- the BJL has no menu item or key-press to run a program from a particular address. You can do this from the DOS loader, however, by running lo with the name of a file which does not exist. Due to a bug, presumably, it does not check for the file first, and sends the 'run' instruction to the BJL anyway. Thus, you can start the program just by typing something like 'lo run' where run does not exist, and it will start the program at the default address of $4000.
While the binary is loading you do not see anything particularly special, the screen flickers in a coloured band over the BJL loader text message, which itself tells you whether the upload is the default 4 bit or 8 bit, and shows the address as it loads, but this is not easy to see as the band flickers so quickly. If the screen goes black for a short time during loading this may not mean failure, often with Underground binaries there are some uncompressed data areas which cause it.
BJL upload tool for DOS
Complete BJL Kit for DOS