Classic Computer Magazine Archive COMPUTE! ISSUE 54 / NOVEMBER 1984 / PAGE 10

VIC Metamorphosis

Help! My VIC is changing. I recently noticed that my character set has been relocated. In the past, when I powered up my VIC, the location for the character set (36869) used to be 240. Now it is 192. Can you tell me why?

Scott D. Killen

Odds are that when you get the value of 192 at powerup, you have 8K or more of expansion memory plugged in. The normal powerup value for the unexpanded VIC is 240. Memory location 36869 does more than just indicate the location of the character set. It also points to the start of screen memory.

When you use 8K or more of expansion memory with the VIC, a few things change. Screen memory moves to 4096–4607, color memory to 37888–38399, and the start of user BASIC moves to 4608. In other words, the value of 36869 is not changing because the character set is moving, but because screen memory is relocating.