R01UH0822EJ0100 Rev.1.00
Page 186 of 1041
Jul 31, 2019
RX13T Group
11. Low Power Consumption
11.7
Usage Notes
11.7.1
I/O Port States
I/O port states are retained in software standby mode. Therefore, the supply current is not reduced if output signals are
high level.
11.7.2
Module Stop State of DTC
Before setting the MSTPCRA.MSTPA28 bit to 1, set the DTCST.DTCST bit of the DTC to 0 to avoid activating the
DTC.
For details, refer to
section 16, Data Transfer Controller (DTCb)
.
11.7.3
On-Chip Peripheral Module Interrupts
Interrupts do not operate in the module stop state. Therefore, if the module stop state is made after an interrupt request is
generated, a CPU interrupt source or a DTC startup source cannot be cleared. For this reason, disable interrupts before
entering the module stop state.
11.7.4
Write Access to MSTPCRA, MSTPCRB, and MSTPCRC
Write accesses to MSTPCRA, MSTPCRB, and MSTPCRC should be made only by the CPU.
11.7.5
Timing of WAIT Instructions
The WAIT instruction is executed before completion of the preceding register write. The WAIT instruction being
executed before the register setting is modified may cause unintended operation. To avoid this, always execute the WAIT
instruction after confirming that the last register setting is done.
11.7.6
Rewrite the Register by DTC in Sleep Mode
Depending on the settings of the OFS0.IWDTSLCSTP bit and IWDTCSTPR.SLCSTP bit, the IWDT may also stop in
sleep mode. To avoid this, do not set up the DTC to rewrite any registers related to the IWDT in sleep mode.