# apple1-videocard-lib

Library and demos for the Apple-1 TMS9918 video card by P-LAB.


# Building for the CodeTank/Juke-Box Expansion Cards

The demo contained in the repo are meant to be launched from the Apple-1 
"CodeTank" EEPROM daughterboard of the "Apple-1 Graphic Card" or "Juke-Box 
Card" FLASH at address $4000. The executables are built according to the 
following memory map:

$0000-$00FF zero page: holds most of C program variables 
$0280-$0FFF low RAM space: C program "Data" segment 
$4000-$7581 EEPROM/FLASH (CodeTank/Juke-Box): C program "Code" segment 
$7582-$7FFF EEPROM/FLASH (CodeTank/Juke-Box): C program "Data" segment (startup values)

The build script `mkeprom.js` creates a 16K binary file to be placed on the 
EEPROM/FLASH where the "Data" segment startup values are put at the end of the 
file itself. The user program need to manually copy such data from EEPROM/FLASH 
to low RAM once after the `main()` is launched. This can be easily done by simply 
calling the library function `apple1_eprom_init()`.