Fujitsu FR81S User Manual
CHAPTER 30: POWER CONSUMPTION CONTROL
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : POWER CONSUMPTION CONTROL
FUJITSU SEMICONDUCTOR CONFIDENTIAL
22
5.3.2. Bus Sleep Mode
This section describes bus sleep mode.
Bus sleep mode is the mode to stop CPU and on-chip bus operations. In this mode, the CPU clock (CCLK)
and on-chip bus clock (HCLK) will stop.
When accepting a DMA transfer request in bus sleep mode, on-chip bus clock (HCLK) supply resumes
temporarily and performs DMA transfers. After the DMA transfer, stop the on-chip bus clock (HCLK)
again.
In this mode, you can decrease the amount of power consumption more than that of CPU sleep mode, but
the response time to the DMA transfer request will be somewhat degraded.
MB91520 Series
MN705-00010-1v0-E
1109