Editing Atari XE Game System (section)

== Boot behaviour and self test ==

* '''No keyboard attached''' - the console starts ''Missile Command'' automatically.<ref name="ratcliff" />
* '''Keyboard attached, no cartridge''' - the console starts Atari BASIC Rev. C. Hold
  '''SELECT''' at power-on to get ''Missile Command'' instead.<ref name="ratcliff" />
* '''Self test''' - hold '''OPTION''' and press '''POWER'''.<ref name="xegsman">Atari Corporation, ''ATARI XE Game System Owner's Manual''. Available at the Internet Archive, item <code>atari-xegs</code>. Source for the boot behaviour, the self-test procedure and the power-connection description.</ref> From a BASIC ready prompt,
  typing '''BYE''' also reaches the self test, but BASIC is not switched off when you do, so the
  8 KB under BASIC is not tested and the memory screen shows 40 RAM squares instead of
  48.<ref name="ratcliff" /><ref name="xegsman" />
* From the self test, pressing '''RESET''' while holding '''SELECT''' goes to ''Missile
  Command''; pressing RESET while holding '''OPTION''' from within ''Missile Command'' returns to
  the self test; RESET on its own returns to BASIC.<ref name="ratcliff" />