R01UH0822EJ0100 Rev.1.00
Page 109 of 1041
Jul 31, 2019
RX13T Group
7. Option-Setting Memory (OFSM)
7.2.2
Option Function Select Register 1 (OFS1)
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 OFS1 register is allocated in the ROM. Set this register at the same time as writing the program. After writing, do
not write additions to this register.
When erasing the block including the OFS1 register, the OFS1 register value becomes FFFF FFFFh.
The setting in the OFS1 register is ignored in boot mode, and this register functions similarly when it is set to FFFF
FFFFh.
VDSEL[1:0] Bits (Voltage Detection 0 Level Select)
These bits select the voltage detection level to be monitored by the voltage detection 0 circuit.
LVDAS Bit (Voltage Detection 0 Circuit Start)
This bit selects whether the voltage monitoring 0 reset is enabled or disabled after a reset.
The Vdet0 voltage to be monitored by the voltage detection 0 circuit is selected by the VDSEL[1:0] bits.
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.
Address(es): OFSM.OFS1 FFFF FF88h
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
—
—
—
—
—
—
—
HOCO
EN
—
—
—
—
—
LVDAS
VDSEL[1:0]
Value after reset:
The value set by the user*
Bit
Symbol
Bit Name
Description
R/W
b1, b0
Voltage Detection 0 Level
Select
b1 b0
0 0: 3.84 V is selected
0 1: 2.82 V is selected
1 0: 2.51 V is selected
Settings other than above are prohibited when the voltage
detection 0 circuit is used.
R
b2
Voltage Detection 0 Circuit
Start
0: Voltage monitoring 0 reset is enabled after a reset
1: Voltage monitoring 0 reset is disabled after a reset
R
b7 to b3
—
Reserved
When reading, these bits return the value written by the user.
The write value should be 1.
R
b8
HOCO Oscillation Enable
0: HOCO oscillation is enabled after a reset
1: HOCO oscillation is disabled after a reset
R
b31 to b9
—
Reserved
When reading, these bits return the value written by the user.
The write value should be 1.
R