mb91307r Fujitsu Microelectronics, Inc., mb91307r Datasheet - Page 17

• Manufacturer Part Number: mb91307r
• Description: 32-bit Microcontroller Cmos Fr60 Mb91307 Series
• Manufacturer: Fujitsu Microelectronics, Inc.

• Low-power consumption modes
• Current at power-on (only for MB91V307R)
• Watchdog timer
About 300 mA of power supply current flows when the power is turned on with INIT set to 0.
Set INIT to 1 to stop the overcurrent flowing. After that, the overcurrent will not flow even if INIT is set to 0.
The watchdog timer function of this model monitors that a program delays a reset within a certain period of time
and resets the CPU if the program fails to delay it, for example, because the program runs out of control. Once
the watchdog timer function is enabled, therefore, the watchdog timer countinues to operate until a reset takes
place.
An exception, for example during stop, sleep and DMA transfer modes, is the automatic delaying of a reset under
a condition in which the CPU stops program execution.
Note, however, that a watchdog reset may not occur in the above state caused when the system runs out of
control. If this is the case, use the external INIT pin to cause a reset (INIT).
• To enter the standby mode, use the synchronous standby mode (set with the SYNCS bit as bit 8 in the
• If you use the monitor debugger, follow the precautions below:
TBCR, or time-base counter control register) and be sure to use the following sequence:
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.
Note : Stop mode (oscillation stop mode) cannot be used.
(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.
#value_of_standby, R0)
#_STCR, R12)
R0, @R12
@R12, R0
@R12, R0
Using external clock (normal)
; Write to standby control register (STCR)
; Read STCR for synchronous standby
; Read STCR again for dummy read
; NOP x 5 for timing adjustment
X0
X1
MB91307 series
MB91307 Series
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