FR65E Fujitsu Microelectronics, Inc., FR65E Datasheet - Page 16

• Manufacturer Part Number: FR65E
• Description: 32-bit Microcontroller
• Manufacturer: Fujitsu Microelectronics, Inc.

16
MB91307B
• Precautions for use of stop mode
• Low-power consumption modes
• Executing instructions on RAM
Sample use of Stop Mode with 3.3 V power supply
The built-in regulator in this device stops operating when the device is in stop mode. In such cases as when
increased leak current (I
operating mode cause the regulator to stop, the internal 2.5 V power supply can ball below the voltage at which
operation is assured. Therefore it is necessary when using the internal regulator and stop mode to assure that
the external power supply does not fall below 3.3 V. And even if this should occur, the internal regulator can be
set to restart when a reset is applied. (In this case the oscillator stabilization wait period should also be set to L
level.)
If instruction codes are placed in RAM, they should not be placed in the last 8 address bytes 0005_FFFF8
0005_FFFF
To enter the standby mode, use the synchronous standby mode (set with the SYNCS bit as bit 8 in the
TBCR, or time-base counter control register) and be sure to use the following sequence:
If you use the monitor debugger, follow the precautions below:
Set the I-flag and the ILM and ICR registers to branch to an interrupt handler when the interrupt handler
triggers the microcontroller to return from the standby mode.
(LDI
STB
(LDI
LDUB
LDUB
NOP
NOP
NOP
NOP
NOP
Do not set a breakpoint within the above array of instructions.
Do not single-step the above array of instructions.
H
. (Instruction code prohibited area)
#value_of_standby, R0)
#_STCR, R12)
R0, @R12
@R12, R0
@R12, R0
CCH
) in stop mode, or abnormal operation or power fluctuation due to noise while in
2.4 k
7.6 k
3.3 V
GND
; Write to standby control register (STCR)
; Read STCR for synchronous standby
; Read STCR again for dummy read
; NOP x 5 for timing adjustment
0.1 F
V
V
C
CC
SS
H
to