R01UH0823EJ0100 Rev.1.00
Page 235 of 1823
Jul 31, 2019
RX23W Group
11. Low Power Consumption
Middle-Speed Operating Mode
As compared to high-speed operating mode, this mode reduces power consumption for low-speed operation.
The maximum operating frequency during FLASH read is 12 MHz for ICLK, FCLK, PCLKA, PCLKB, and PCLKD.
The operating voltage range is 1.8 to 3.6 V during FLASH read. The maximum operating frequency during FLASH read
is 8 MHz for all the clocks when the operating voltage is 1.8 V or larger and smaller than 2.4 V.
During FLASH programming/erasure, the operating frequency range is 1 to 12 MHz and the operating voltage range is
1.8 to 3.6 V. The maximum operating frequency during FLASH programming/erasure is 8 MHz when the operating
voltage is 1.8 V or larger and smaller than 2.4 V.
The power consumption of this mode is lower than that of high speed mode under the same conditions.
After a reset is canceled, operation is started from this mode.
The following restriction applies when middle-speed operating mode is selected:
The PLL and USB-dedicated PLL can be used when the operating voltage is 2.4 V or above.
However, the USB cannot be used when the operating voltage is below 3.0 V.
shows the operating voltages and frequencies in middle-speed operating mode.
Figure 11.4
Operating Voltages and Frequencies in Middle-Speed Operating Mode
Note:
When using the FCLK at lower than 4 MHz during programming or erasing the flash memory, the frequency can
be set to 1, 2, or 3 MHz.
[V]
3.6
2.7
2.4
1.8
0.032768
1 4 8 12 16 20 25
32
50 54
ICLK, PCLKA, PCLKD
[MHz]
[V]
3.6
2.7
2.4
1.8
0.032768
1 4 8 12 16 20 25
32
50 54
PCLKB, FCLK
[MHz]
[V]
3.6
2.7
2.4
1.8
0.032768
1 4 8 12 16 20 25
32
50 54
FCLK (P/E only)
[MHz]
