Developer Resources

AS6502--A Cross-Assembler for the 6502
Supports undocumented opcodes, includes source and executables for 16-bit DOS.
http://www.whimsey.com/as6502/

Bob Colbert's Web Page
Bob Colbert's Stella Resources, including commented source code and the DASM Assembler.
http://members.cox.net/rcolbert/

How I Built My Custom Atari 2600 Cartridge
Includes images, diagrams, and links.
http://es.geocities.com/gamemasterquilpue/myownataricart_e.htm

Mactari Tools Page
2600 development tools for PowerPC Macs.
http://members.aol.com/mactari/

MAS65--6502 Macro Cross Assembler
For Z80 CP/M and DOS systems, source available.
http://www.hytherion.com/beattidp/comput/x65tools/

Nick Bensema's Atari 2600 Programming Page
Tools, sample sources, disassembled games, and home-brewed binaries.
http://www.io.com/~nickb/atari/