6523A-28

Function:

• The TPI (Tri-Port Interface) is an I/O chip with 3 8 bit parallel  ports
  this 28 version is identical with the normal 40 pin 6523 version, but not all pins are connected to the outside
• the 6523 that doesn’t have interupts

Used in:

• 1551 Drive Dongle

Datasheets:

• 6523 Datasheet