Description of video registers for:

 

Texas Instruments TMS9918A

Texas Instruments TMS9928A

Texas Instruments TMS9929A

 

Used in Texas Instruments TI-99/4A Home Computer, ColecoVision, Memotech MTX, MSX, Sega SG-1000/SC-3000, Spectravideo, Sord M5, Tatung Einstein and Tomy Tutor/Pyuuta

 

0

0

0

0

0

0

Bitmap Mode

External Video = 0

4K / 16K = 1

Screen Active

Interrupt Enable

Text Mode

Multicolour Mode

0

Sprite Size

Sprite Magnification

0

0

0

0

Screen Image Table Address >400

i.e. represents 0-15 multiples of 1 kB

Non-Bitmap modes: Colour Table Address >40, i.e. 0-255 multiples of 64 (not applicable in Text or Multicolour modes)

Bitmap mode: MSb=0 makes colour table @V>0000, MSB=1 makes colour table @V>2000,

and remaining bits become bits >6 to >C of an address mask.

0

0

0

0

0

Pattern Table Address >800

i.e. represents 0-7 multiples of 2 kB

0

Sprite Attribute Table Address >80

i.e. represents between 0 and 127 multiples of 128

0

0

0

0

0

Sprite Pattern Table Address >800

i.e. represents 0-7 multiples of 2 kB

Text Mode foreground colour

All Modes Background colour

End of Scan

Coincidence

Five Sprites

Number of Fifth Sprite, if applicable [0-31]