R2025S/D
*1), *2) When the oscillation adjustment circuit is used, the interrupt cycle will fluctuate once per 20sec. or
60sec. as follows:
Pulse Mode: The “L” period of output pulses will increment or decrement by a maximum of
±3.784
ms. For
example, 1-Hz clock pulses will have a duty cycle of 50
±0.3784%.
Level Mode: A periodic interrupt cycle of 1 second will increment or decrement by a maximum of
±3.784
ms.
•
Control Register 2 (Address Fh)
D7
VDSL
VDSL
0
*)
D6
VDET
VDET
0
Default settings:
D5
/XST
/XST
Indefinit
e
D4
PON
PON
1
D3
/CLE
N1
/CLE
N1
0
D2
CTFG
CTFG
0
D1
WAF
G
WAF
G
0
D0
DAFG
DAFG
0
(For Writing)
(For Reading)
Default Settings *)
Default value means read / written values when the PON bit is set to “1” due to VDD
power-on from 0 volts.
(1) VDSL
VDSL
VDD Supply Voltage Monitoring Threshold Selection Bit
(Default)
Description
0
Selecting the VDD supply voltage monitoring threshold setting of
2.1v.
1
Selecting the VDD supply voltage monitoring threshold setting of
1.3v.
The VDSL bit is intended to select the VDD supply voltage monitoring threshold settings.
(2) VDET
VDET
Supply Voltage Monitoring Result Indication Bit
Description
0
Indicating supply voltage above the supply voltage monitoring
(Default)
threshold settings.
1
Indicating supply voltage below the supply voltage monitoring
threshold settings.
Once the VDET bit is set to 1, the supply voltage monitoring circuit will be disabled while the VDET bit will
hold the setting of 1. The VDET bit accepts only the writing of 0, which restarts the supply voltage
monitoring circuit. Conversely, setting the VDET bit to 1 causes no event.
(3) /XST
Oscillation Halt Sensing Monitor Bit
/XST
Description
0
Sensing a halt of oscillation
1
Sensing a normal condition of oscillation
The /XST accepts the reading and writing of 0 and 1. The /XST bit will be set to 0 when the oscillation halt
sensing. The /XST bit will hold 0 even after the restart of oscillation.
(4) PON
Power-on-reset Flag Bit
PON
Description
0
Normal condition
1
Detecting VDD power-on -reset
(Default)
The PON bit is for sensing power-on reset condition.
* The PON bit will be set to 1 when VDD power-on from 0 volts. The PON bit will hold the setting of 1 even
after power-on.
* When the PON bit is set to 1, all bits will be reset to 0, in the Oscillation Adjustment Register, Control
Register 1, and Control Register 2, except /XST and PON. As a result, /INTRA and /INTRB pins stop
outputting.
* The PON bit accepts only the writing of 0. Conversely, setting the PON bit to 1 causes no event.
13
RICOH [ RICOH ELECTRONICS DEVICES DIVISION ]
