FR60 MB91460E Series - Microcontrollers - Fujitsu

MB91460E Series
4. Shutdown Operation
4.1. Transition to shutdown state
Shutdown state is a special kind of the STOP state. During Shutdown, the settings in the STCR register for
Oscillation Disable (STCR.OSCD1, STCR.OSCD2), Hi-Z mode (STCR.HIZ) and Oscillation Stabilization time
(STCR.OS[1:0]) are valid the same kind as in normal STOP state. At recovery from Shutdown, STCR.OS[1:0]
are not cleared to maintain the oscillator stabilisation time, while STCR.OSCD1, STCR.OSCD2 and STCR.HIZ
are initialized by the recovery.
For transition into Shutdown, do the following:
• Enable at least one recovery condition (otherwise, recovery is only possible by external INITX pin)
• Enable the Shutdown mode
• Switch the device to STOP mode
The details are explained below.
4.1.1. Precautions
Before enabling Shutdown, consider the following:
• Data, which is needed after recovery from Shutdown, should be copied into the Standby RAM.
• The CPU should run on Main- or Sub-Oscillation, not on PLL. The PLL should be disabled.
• The Sub-Regulator can be set to 1.2V in STOP mode by setting REGSEL.SUBSEL = 0x00
• Specify the levels of external interrupt signals used for recovery in EXTLV1/2 registers
• Enable the channels of external interrupt signals for recovery in EXTE register
4.1.2. Deep Shutdown Settings for maximal power saving
The following settings generate Shutdown without any activity on the device:
• Disable all pin pull-up/pull-down settings which are not required, or set the STCR.HIZ 1 bit when going to STOP.
• Set external bus pins to port mode / input direction (otherwise some pins will output constant values,
see “I/O Behaviour in Shutdown” on page 91).
• Don’t set Hardware Watchdog Run in STOP mode (HWWDE.STP_RUN 2 =0, this is default setting)
• Disable the RC oscillator in STOP mode (CSVCR.RCE=0)
• Disable the Low Voltage Detection in STOP mode (LVDET.LVEPD=1, LVDET.LVIPD=1)
• Disable the Main and the Sub oscillators in STOP mode (STCR.OSCD1=1, STCR.OSCD2=1)
• Set the Shutdown Enable bit SHDE.SDENB=1 to enable shutdown mode
• Go to STOP: set the STOP request STCR.STOP=1 and read back STCR two times.
1. With STCR.HIZ=1, all pull-ups and pull-downs are disabled in STOP/Shutdown.
2. STP_RUN is bit [4] of HWWDE register. It enables running the Hardware Watchdog in STOP mode.
STP_RUN can only be set by software, but not cleared. STP_RUN is cleared by INIT.
84 DS705-00002-1v3-E