HD64F36022 datasheet(102/384 Pages) RENESAS

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Section 6 Power-Down Modes

Rev. 4.00 Sep. 23, 2005 Page 76 of 354

REJ09B0025-0400

6.3

Operating Frequency in Active Mode

Operation in active mode is clocked at the frequency designated by the MA2 to MA0 bits in

SYSCR2. The operating frequency changes to the set frequency after SLEEP instruction

execution.

6.4

Direct Transition

The CPU can execute programs in active mode. The operating frequency can be changed by

making a transition directly from active mode to active mode. A direct transition can be made by

executing a SLEEP instruction while the DTON bit in SYSCR2 is set to 1. The direct transition

also enables operating frequency modification in active mode. After the mode transition, direct

transition interrupt exception handling starts.

If the direct transition interrupt is disabled in interrupt enable register 1, a transition is made

instead to sleep mode. Note that if a direct transition is attempted while the I bit in CCR is set to 1,

sleep mode will be entered, and the resulting mode cannot be cleared by means of an interrupt.

6.5

Module Standby Function

The module-standby function can be set to any peripheral module. In module standby mode, the

clock supply to modules stops to enter the power-down mode. Module standby mode enables each

on-chip peripheral module to enter the standby state by setting a bit that corresponds to each

module in MSTCR1 and MSTCR2 to 1 and cancels the mode by clearing the bit to 0.

HD64F36022 Datasheet(PDF) 102 Page - Renesas Technology Corp