Editing Psion Series 5 (section)

=== Reset ===

Two distinct resets, and knowing which is which matters when a machine misbehaves:<ref name="sm" />

* '''Power-On Reset (cold reset)''' — generated by a '''Ricoh RN5VLR20AA''' open-drain voltage detector (IC4) when VDD crosses a threshold set to '''2.0 V ± 2.5 %'''. An RC network stretches the low state to give the ARM 7100 time to reset. '''A cold reset erases everything held in volatile storage''' and indicates that all power was lost and re-applied.
* '''User Reset (warm reset)''' — a switch that '''forms part of the lithium backup battery's negative contact''', normally reachable only by opening the backup battery cover and using a pointed instrument. Held inactive high by pull-up R1, with a small capacitor C113 providing noise bypass to protect against inadvertent resets during ESD events. '''All user data should survive a warm reset.'''