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.
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
Endian Select
b2 b0
0 0 0: Big endian
1 1 1: Little endian
Settings other than above are prohibited.
R
b31 to b3
—
Reserved
When reading, these bits return the value written by the user.
The write value should be 1.
R