Hi,
I thought I'd post this snippet from my web page regarding the
Supercharger format. I know the problem has been addressed, but I think
that there was one mistake regarding the "bank byte" so the info is
reproduced here. Using what Eckhard wrote will work for MOST loads, but
there is one load
for sure that uses calculated bank bytes, but I don't remember which.
Contents:
byte # Description
------ -----------
1 Start Address Lo-Byte
2 Start Address Hi-Byte
3 Control Byte
This is the control byte,
it determines the bankswitching
mode of the SC.
Bits Function
------ --------
D7-D5 Write Pulse Delay (Set to 0)
D4-D2 RAM/ROM Configuration
Value $f000 $f800
----- ----- -----
000 3 ROM
001 1 ROM
010 3 1
011 1 3
100 3 ROM
101 2 ROM
110 3 2
111 2 3
4 # of pages to load
(1 page = 256 bytes)
5 Data Header Checksum
The 8 bytes in the Data Header must
add up to #$55 (hex).
6 Multi-load byte
Zero for single-load games. For Multi-Load
games you need to know what value the game is
looking for. For Supercharger 8448 byte files
this value is contained in the file.
7 Lo-byte Bar Speed byte
This is the lo-byte of the speed at which
the bars move across the screen upon loading
the game. Supercharger Fastload uses #$42.
8 Hi-byte Bar Speed byte
This is the hi-byte of the speed at which
the bars move across the screen upon loading
the game. Supercharger Fastload uses #$02.
Section: Page Header
Contents:
byte # Description
------ -----------
1 Bank Byte - Tells Supercharger where to load
the current page (256 bytes) into. This is
determined as follows:
Bank Byte Bits: 7 6 5 4 3 2 1 0
\_______/ \/
Page # Bank #
For example, a page loaded into bank 3, page 4
would have a page # of 000100 and a bank # of
11, combining these together you get 00010011
for a Bank Byte of #$13. The simple formula to
calculate the Bank Byte is:
(Page # * 4) + Bank #
2 Page Checksum - This byte is equal to:
#$55 - (sum of all 256 bytes in page)
Section: Data Page
Contents: 256 bytes of data
.
.
.
The Page Header and Data Page sections are repeated
for each page in the file to be loaded.
Hope this helps!
Bob
--
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
