Address 650 ($28A) holds a pair of flags in its two most significant bits, to indicate which keys on the keyboard should repeat when pressed down for more than about a half second: In the standard mode (after a cold start, i.e. power-up or reset), the binary contents of address 650 is 00xxxxxx, which causes the space bar, the cursor control keys, and the key to repeat.
There are three different settings:
- 00xxxxxx: Only the space bar, cursor keys, and INST/DEL repeats.
- 01xxxxxx: No keys repeat
- 1xxxxxxx: All keys (that causes visible characters to appear on the screen) repeat.
The last mode, with all keys repeating, also influences the mechanism that allows the user to switch character set using the Shift and Commodore logo key: In the "repeat all keys"-mode, the character set "flickers" back and forth several times, sometimes ending up back at the initial charset.