 newsgroup sci electron path edu!rochest!udel!gatech!howland reston an net!noc net!da-new harvard edu!endor!squish from squish endor uucp shishin yamada subject re atari 2600 processor messag-id 1993apr26 072040 13014 da harvard sender usenet da harvard network new organ aiken comput lab harvard univers refer 93110 125951pca103 psuvm psu 1993apr21 081317 599 da harvard 1r7e14 l2c sunb oc mq au date mon 26 apr 1993 07 20 40 gmt line 71 in articl 1r7e14 l2c sunb oc mq au ifarqhar laurel oc mq au ian farquhar write in articl 1993apr21 081317 599 da harvard squish endor uucp shishin yamada write the atari 2600 6502 cpu entir 8-bit 400 800 1200 1400 1440 130xe 65xe comput well 5200 game machin wrong 6507 sorri ian toi year insid year post lag dai thought i'd toss 0 02 assum 6507 function 6502 mo technolog? vers 6502 base atari comput the 2600 the 2600 extra asic chip basic modifi graphic chip pia's joystick it custom chip asic sens word understood tia 6526 manufactur list cia complex interfac adapt tia stand televis interfac adapt handl sound paddl minim video hardwar 2600 possess in atari comput cia chip refer sound aw lot ctia color televis interfac adapt chip earli model later atari upgrad gtia graphic other color literatur state gtia stood georg develop chip there standard 6532 ram o timer riot voltag regul memori serv 555 timer that's later model 2600 incorpor chip asci weight machin count decreas lot year not servic document the 2600 chang inten funni model the significantli heavier addition 2600 2k 4k 8k rom game rom map upper 4k 6507's address space 2k 4k game fine 8k 16k game need bank switch atari huge cartridg idea ram work hazard guess 2 4k ram sorri my microcontrol built mc68701 base chipset 128 byte onboard that easi work addtion small 2k on-board eprom wrong 128 byte ram riot thi multipli map 0 pseudo-regist 1 stack bottom 4k memori tia regist sat address space as 128 byte ram limit cartridg carri ram interest atari provid write cart thi manag map read ram address rang write time scheme at scarc rom address space ian 