Reducing Power Consumption By Switching Clock Signals; Module Stop Function - Renesas RX100 Series User Manual

RX13T Group
11.3

Reducing Power Consumption by Switching Clock Signals

The clock frequency can change by setting the SCKCR.FCK[3:0], ICK[3:0], PCKB[3:0], and PCKD[3:0] bits. The CPU,
DTC, ROM, and RAM clocks can be set by the ICK[3:0] bits. The peripheral module clocks can be set by the PCKB[3:0]
and PCKD[3:0] bits.
The flash memory clock can be set by the FCK[3:0] bits.
For details, refer to section 9, Clock Generation Circuit .
11.4

Module Stop Function

The module stop function can be set for each on-chip peripheral module.
When the MSTPmi bit (m = A to C; i = 0 to 31) in MSTPCRA to MSTPCRC is set to 1, the specified module stops
operating and enters the module stop state, but the CPU continues to operate independently. When the corresponding
MSTPmi bit is set to 0, the module exits the module state and restarts operating at the end of the bus cycle. The internal
states of modules are retained in the module stop state.
After a reset is canceled, all modules other than the DTC, and on-chip RAM are in the module stop state. Basically the
registers in the module stop state cannot be read or written. However, note that data may be written to these registers if
write access is made immediately after the setting of the module stop state. To avoid this, always write to the module
stop registers after confirming that the last register setting is done.
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
11. Low Power Consumption
Page 177 of 1041