RX610 Group
8. Low Power Consumption
R01UH0032EJ0120 Rev.1.20
Page 190 of 1006
Feb 20, 2013
8.5.2
All-Module Clock Stop Mode
8.5.2.1
Transitions to All-Module Clock Stop Mode
When the following two conditions are satisfied, executing the WAIT instruction with the SSBY bit in SBYCR cleared to
0 will cause the transition to all-module clock stop mode at the end of the bus cycle.*
1
•
The ACSE bit in MSTPCRA is set to 1.
•
All the modules controlled by the MSTPCRA and MSTPCRB registers except for the 8-bit timers (units 0 and 1)
are set in the module stop state (MSTPCRA = FFFFFF[C to F]Fh, MSTPCRB = FFFFFFFFh).
In all-module clock stop mode, the CPU, the bus controller, the I/O ports, and all the peripheral modules except for the
8-bit timers*
2
and the watchdog timers are stopped.
If a further reduction in supply current is required beyond that in all-module clock stop mode, stop the target modules for
which operation or stopping is controlled by MSTPCRC.
When all-module clock stop mode is in use, issue a WAIT instruction after making the following settings.
1. Clear the I bit
*
3
in PSW of the CPU to 0.
2. Set the priority
*
4
of the interrupt to be used for recovery from all-module clock stop mode to a level higher than the
setting of the IPL[2:0] bits
*
3
in PSW.
3. Set the IENj bit
*
4
in IERm for the interrupt to be used for recovery from all-module clock stop mode to 1.
4. Make either of the following settings for interrupts that are not to be used for recovery from all-module clock stop
mode.
•
Set the priority*
4
of interrupts*
5
that are not to be used for recovery from all-module clock stop mode to a level
lower than the setting of the IPL[2:0] bits*
3
in PSW of the CPU.
•
Set the IENj bit*
4
in IERm for the interrupt*
5
that is not to be used for recovery from all-module clock stop
mode to 0.
5. Execute a WAIT instruction (executing a WAIT instruction causes automatic setting of the I bit
*
3
in PSW of the
CPU to 1).
Notes: 1. The state of DTC or DMAC operations can make transitions to module stop mode impossible. 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 the DTC or DMAC is not initiated.
2. The MSTPA4 and MSTPA5 bits of the MSTPCRA register select operation or stopping of these modules.
3. For details, see section 2, CPU.
4. For details, see section 10, Interrupt Control Unit (ICU).
5. Executing a WAIT instruction while a peripheral module is operating creates a possibility of recovery from
all-module clock-stop mode being triggered by an interrupt that could not normally act as a trigger for
recovery. Interrupts that can act as triggers for recovery thus include all interrupts which can be set by the
various IERm.IENj bits and the PSW.IPL[2:0] bits, as well as the interrupts that are intended to act as triggers
for recovery.