Chapter 8 — Scanning and Persistence of Vision

This chapter will explain the timing trick behind the TEC-1G displays.

Planned coverage:

  • why the six digits are not all independently latched
  • showing one digit at a time
  • cycling quickly enough that the eye sees a stable display
  • the old television analogy: scan repeatedly and depend on persistence of vision
  • what happens when the scan loop is too slow
  • why hardware refresh becomes part of the program’s job
  • how this same idea prepares you for the 8x8 RGB matrix

This is the conceptual hinge of Book 2. Once scanning is clear, the six-digit display, one-bit sound service, and 8x8 matrix all become easier to understand.