R01UH0823EJ0100 Rev.1.00
Page 153 of 1823
Jul 31, 2019
RX23W Group
7. Option-Setting Memory (OFSM)
7.2.2
Option Function Select Register 1 (OFS1)
Note 1. Set the same value to this address when using start-up program protection.
Note 2. 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.
Set the voltage detection 0 level to 2.51 V (set VDSEL[1:0] bits to 10b) before using the battery backup function (setting
the VBATTCR.VBATTDIS bit to 0).
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.
FASTSTUP Bit (Power-On Fast Startup Time)
The startup time can be reduced by setting this bit to 0 (fast startup time at power on) when it is possible to meet the
power-on VCC rising gradient (during fast startup time) shown in Electrical Characteristics. Do not set this bit to 0 when
it is not possible to meet the power-on VCC rising gradient (during fast startup time).
Address(es): OFSM.OFS1 FFFF FF88h, (FFFF 7F88h)*
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
—
—
—
—
FASTS
TUP
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: Settings prohibited
0 1: 2.82 V is selected
1 0: 2.51 V is selected
1 1: 1.90 V is selected
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
b3
Power-On Fast Startup Time 0: Fast startup time at power on
1: Normal startup
R
b7 to b4
—
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