RX610 Group
8. Low Power Consumption
R01UH0032EJ0120 Rev.1.20
Page 202 of 1006
Feb 20, 2013
8.7
Usage Notes
8.7.1
I/O Port States
I/O port states are retained in software standby mode and deep software standby mode. Therefore, supply current is not
reduced while output signals are held high.
8.7.2
Module Stop State of the DMAC and DTC
Before setting the MSTPA28 or MSTPA27 bits in MSTPCRA to 1, clear the DMST bit in DMSCNT of the DMAC and
the DTCST bit in DTCST of the DTC to 0 so that initiating transfer by the DTC or DMAC is not possible. For details,
see section 12, DMA Controller (DMAC) and section 13, Data Transfer Controller (DTC).
8.7.3
On-Chip Peripheral Module Interrupts
Operation of relevant interrupt is disabled in the module stop state. Therefore, if the module stop state is made with an
interrupt request pending, a CPU interrupt source or a DMAC (or DTC) startup source cannot be cleared. For this reason,
disable interrupts before entering the module stop state.
8.7.4
Write-Access to MSTPCRA, MSTPCRB, and MSTPCRC
Write-accesses to MSTPCRA, MSTPCRB, and MSTPCRC should be made only by the CPU.
8.7.5
Input Buffer Control by DIRQnE Bit (n = 3 to 0)
The input buffers for the P30/IRQ0-A to P33/IRQ3-A pins are enabled by setting the DIRQnE bit (n = 3 to 0) in DPSIER
to 1. Therefore, note that inputs to these pins are reflected in the DIRQnF flag (n = 3 to 0) in DPSIFR, but are not
transferred to the interrupt control unit, peripheral modules, and I/O ports. Inputs to the interrupt control unit, peripheral
modules, and I/O ports should be controlled by each Pn.ICR.
8.7.6
Conflict between Transition to Deep Software Standby Mode and Interrupt
If a conflict occurs between a transition to deep software standby mode and generation of a software standby mode
canceling source, the transition to deep software standby mode is not realized but the software standby mode canceling
sequence is started. After the oscillation settling time specified by the STS[4:0] bits in SBYCR for software standby
mode has passed, the interrupt exception handling is started.
Note that if a conflict occurs between a transition to deep software standby mode and generation of an NMI interrupt, the
NMI interrupt exception handling routine is required.
If a conflict occurs between a transition to deep software standby mode and generation of an interrupt of IRQ0 to IRQ15,
a transition to deep software standby mode can be made by clearing the SSIj bit (j = 15 to 0) in SSIER of the ICU to 0
beforehand without starting the interrupt exception handling.
8.7.7
Timing of Wait Instructions
The WAIT instruction is executed before completion of the preceding register write; it may be executed before the
register modification is reflected, causing unintended operation. To avoid this, execute the WAIT instruction after
confirming that the last write to the register has been completed.
Summary of Contents for RX600 Series
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