Video game external memory arrangement with reduced memory requirements

An external video game memory arrangement for coupling to a video game system having:

• (a) a picture processing unit including an attribute table memory, a temporary memory coupled to said attribute table memory, a buffer memory coupled to said temporary memory, and background signal generation circuitry;
• (b) a video signal synthesizer means coupled to said picture processing unit for outputting composite video signals defining video frames for display by a television set, said video signals including line scanning periods, horizontal blanking periods, and vertical blanking periods, and (c) a programmable processor coupled to and cooperating with said picture processing unit, said external memory arrangement comprising:
• an external character generator coupled to said picture processor unit, said character generator for providing first character data for storage into said buffer memory during horizontal blanking periods in response to character identification data stored in said temporary memory, and providing further character data to said background signal generation circuitry during line scanning periods, and
• a program memory for coupling to said programmable processor, said program memory providing at least program control instructions for execution by said programmable processor so as to effect writing of data specifying character identification and position into said attribute table memory during a vertical blanking period associated with a video frame, said character position data being selectively written from said attribute memory into said temporary memory during line scanning and subsequently written from said temporary memory into said buffer memory during horizontal blanking for use in generating composite video signals during a next subsequent video line scanning period.