PC200 DIP switches
The Sinclair PC200 has 6 DIP switches, but only 5 are used.
SW1: Boot drive
If SW1 is off and a second floppy drive is present, then the PC will boot from the second drive. This switchover happens at the BIOS level rather than the hardware, so programs which try to bypass the BIOS and manipulate the drive directly will get confused.
This functionality is present in BIOS 1.5, but not in the earlier 1.2.
SW2,3: Video hardware
|Off||Off||Built-in chipset emulating MDA, monitor output|
|Off||On||Built-in chipset emulating CGA, monitor output|
|On||Off||Disable built-in chipset, use add-on card|
|On||On||Built-in chipset emulating CGA, television output|
SW4,5: Initial Video Mode
|Off||Off||Add-on EGA or VGA|
|Off||On||Add-on or built-in CGA, 40 columns|
|On||Off||Add-on or built-in CGA, 80 columns|
|On||On||Add-on or built-in MDA, 80 columns|
John Elliott 20 June 2009