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R01UH0823EJ0100 Rev.1.00 Page 154 of 1823

Jul 31, 2019

RX23W Group 7. Option-Setting Memory (OFSM)

HOCOEN Bit (HOCO Oscillation Enable)

This bit selects whether the HOCO oscillation is effective or not after a reset.

Setting the HOCOEN bit to 0 allows the HOCO oscillation to be started before the CPU starts operation, and therefore

reduces the wait time for oscillation stabilization.

Note that even if the HOCOEN bit is set to 0, the system clock source is not switched to HOCO. The system clock source

is switched to HOCO only by modifying the clock source select bits (SCKCR3.CKSEL[2:0]) from the CPU.

Also, when the HOCOEN bit is set to 0, the HOCO oscillation stabilization time (tHOCO) is secured by hardware, so the

clock with the accuracy of the HOCO oscillation frequency (fHOCO) shown in Electrical Characteristics is supplied

after release from the CPU reset state.

7.2.3 Endian Select Register (MDE)

Note 1. The value of the blank product is FFFF FFFFh. This register is set to a specified value after programming of the flash memory

with the user program.

The MDE register selects the endian for the CPU. In single-chip mode, the endian select register (MDE) at address FFFF

FF80h is used to select the endian.

MDE is allocated in the ROM. Set the register at the same time as writing the program. After writing to the register once,

do not write to it again.

When erasing the block including the MDE register, the MDE register value becomes FFFF FFFFh.

MDE[2:0] Bits (Endian Select)

These bits select little endian or big endian for the CPU.

The endian is determined by the value at address FFFF FF80h in the user area when operating in single-chip mode.

Address(es): OFSM.MDE FFFF FF80h

b31 b30 b29 b28 b27 b26 b25 b24 b23 b22 b21 b20 b19 b18 b17 b16

————————————————

Value after reset:

The value set by the user*

b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0

————————————— MDE[2:0]

Value after reset:

The value set by the user*

Bit Symbol Bit Name Description R/W

b2 to b0 MDE[2:0] Endian Select

b2 b0

0 0 0: Big endian

1 1 1: Little endian

Settings other than above are prohibited.

b31 to b3 — Reserved When reading, these bits return the value written by the user.

The write value should be 1.

Renesas RX Series User Manual

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