DS80C390_00 Datasheet, PDF (22/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

RGSL
Bit 1
BGS
Bit 0
DS80C390 High-Speed Microcontroller User’s Guide Supplement
Ring Oscillator Select. This bit selects the clock source following a resume from
Stop mode. Using the ring oscillator to resume from Stop mode allows almost
instantaneous start-up. This bit is cleared to 0 after a power-on reset, and
unchanged by all other forms of reset. The state of this bit will be undefined on
devices which do not incorporate a ring oscillator.
0 = The device will hold operation until the crystal oscillator has warmed-up.
1 = The device will begin operating from the ring oscillator, and when the crystal
warm-up is complete, will switch to the clock source indicated by the XT/ RG
bit.
Band-gap Select. This bit enables/disables the band-gap reference during Stop
mode. Disabling the band-gap reference provides significant power savings in
Stop mode, but sacrifices the ability to perform a power fail interrupt or power-
fail reset while stopped. This bit can only be modified with a Timed Access
procedure.
0 =The band-gap reference is disabled in Stop mode but will function during
normal operation.
1 = The band-gap reference will operate in Stop mode.
22 of 155