The TIA (as seen by the programmer)
1.0 General Description
The TIA is a custom IC designed to create the TV picture
and sound from the instructions sent to it by the
microprocessor. It converts the 8 bit parallel data from
the microprocessor into signals that are sent to video
modulation circuits which combine and shape those signals
to be compatible with ordinary TV reception. A playfield
and 5 moveable objects can be created and manipulated by
software.
A playfield consisting of walls, clouds, barriers, and
other seldom moved objects can be created over a colored
background. The 5 moveable objects can be positioned
anywhere, and consists of 2 players, 2 missiles, and a
ball. The playfield, players, missiles, and ball are
created and manipulated by a series of registers in the TIA
that the microprocessor can address and write into. Each
type of object has certain defined capabilities. For
example, a player can be moved with one instruction, but
the playfield must be completely re-drawn in order to make
it move.
Color and luminosity (brightness) can be assigned to the
background, playfield, and 5 moveable objects. Sound can
also be generated and controlled for volume, pitch, and
type of sound. Collisions between the various objects on
the TV screen are detected by the TIA and can be read by
the microprocessor . Input ports which can be read by the
microprocessor give the status of some of the various hand
held controllers.