Programs containing VIC20 specific code may use the vic20.h
or cbm.h
header files. Using the later may be an option when writing code for more than
one CBM platform, since it includes vic20.h
and declares several functions
common to all CBM platforms.
There are currently no special VIC20 functions.
Some functions are available for all (or at least most) of the Commodore machines. See the function reference for declaration and usage.
The following pseudo variables declared in the vic20.h
header file do allow
access to hardware located in the address space. Some variables are
structures, accessing the struct fields will access the chip registers.
VIC
The VIC
structure allows access to the VIC (the graphics
controller). See the _vic.h
header file located in the include
directory for the declaration of the structure.
VIA1, VIA2
Access to the two VIA (versatile interface adapter) chips is available via
the VIA1
and VIA2
variables. The structure behind these variables
is explained in _6522.h
.
COLOR_RAM
A character array that mirrors the color RAM of the VIC20 at $9600.