The following tables list the functions that can be accessed for each type:
Type Types 0/2:
{| class="wikitable"
|}
Type 1:
{| class="wikitable"
|}
Type 2{| class="wikitable"!b1!b0!Function!Read/Write|-|0||0||Select internal 6845 register||Write Only |-|0||1||Write to selected internal 6845 register||Write Only |-|1||0||-||- |-|1||1||Read from selected internal 6845 register||Read Only |-|}Type Types 3 and /4: