7 X 21 Display

A 7x21 display refers to a matrix with 7 rows and 21 columns, allowing for more detailed visuals than a standard 7-segment display. It can display text, graphics, or animations, commonly used in advanced visual applications.

Structure of a 7×21 Display:

1. LED Arrangement:

   • 21 Columns and 7 Rows of LEDs.
   • Each LED is positioned at the intersection of a column and row.
   • Cathodes (negative terminals) connect to rows, and anodes (positive terminals) connect to columns (or vice versa).

2. Control Pins:

   • Typically requires 28 control lines (7 for rows, 21 for columns).
   • Multiplexing reduces the number of pins needed by controlling LEDs in sequences.