MB90641A Datasheet, PDF (45/96 Pages) Fujitsu Component Limited. – 16-bit Proprietary Microcontroller

MB90640A Series
10. Low-power Control Circuits (CPU Intermittent Operation Function, Oscillation Stabilization
Delay Time, and Clock Multiplier Function)
The following operation modes are available: PLL clock mode, PLL sleep mode, timer mode, main clock mode,
main sleep mode, stop mode, and hardware standby mode. Operation modes other than PLL clock mode are
classified as low-power consumption modes.
In main clock mode and main sleep mode, the device operates on the main clock only (OSC oscillator clock).
The PLL clock (VCO oscillator clock) is stopped in these modes and the main clock divided by 2 is used as the
operating clock.
In PLL sleep mode and main sleep mode, the CPU’s operating clock only is stopped and other elements continue
to operate.
In timer mode, only the timebase timer operates.
Stop mode and hardware standby mode stop the oscillator. These modes maintain existing data with minimum
power consumption.
The CPU intermittent operation function provides an intermittent clock to the CPU when register, internal memory,
internal resource, or external bus access is performed. This function reduces power consumption by lowering
the CPU execution speed while still providing a high-speed clock to internal resources.
The PLL clock multiplier ratio can be set to 1, 2, 3, 4 by the CS1, CS0 bits.
The WS1, WS0 bits set the delay time to wait for the main clock oscillation to stabilize when recovering from
stop mode or hardware standby mode.
(1) Register Configuration
• Low-power consumption mode control register
Address : LPMCR: 0000A0H
bit 7
STP
W
bit 6
SLP
W
bit 5
SPL
R/W
bit 4 bit 3 bit 2
RST Reserved CG1
W — R/W
bit 1 bit 0
CG0 Reserved
R/W —
Initial value
00011000B
• Clock select register
bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9
Address : CKSCR: 0000A1H Reserved MCM WS1 WS0 Reserved MCS CS1
— R R/W R/W — R/W R/W
bit 8
CS0
R/W
R/W : Readable and writable
R : Read only
W : Write only
Initial value
11111100B
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