Character Map

Updated: April 18, 2023 at 13:44 CEST

Character map combined with attribute map creates BG_1 - second of the three layers of graphics.

$9000 - $93FF (Read/Write)

💡 Columns are being stored in RAM from right to left. First visible column starts at $93A0 and ends at $93BF. Last visible column starts at $9040 and ends at $905F respectively. These are also addresses for top left, bottom left, top right and bottom right characters visible on the layer.

BG_1 is used for text, bottom part of title screen logo, HUD, stage borders, platforms and bombs. It has priority above BG_0 but below OBJ. Main features are:

  • array of 32 columns, 32 rows each
  • each entry is 1 byte and represents 1 character code (8x8 pixel block also called tile) from bank 0
  • up to 512 unique characters is possible thanks to corresponding attribute map entry
  • first and last two columns remain off screen (screen resolution is 224*256)