Interface Timing When Power Is Turned On / Off; Restrictions Of I 2 C-Bus Interface In The Initial Power On; Precautions For Power On / Off - Epson RX8130CE Applications Manual

10. Interface timing when power is turned ON / OFF

2
10.1. Restrictions of I C-Bus interface in the initial power on.
The operation of the RTC register is linked to the oscillation clock of the built-in crystal unit.
Therefore, it will not operate normally when the oscillation is stopped.
It is recommended that the initialization at the time of initial power-on is performed after the oscillation start time t_str
characteristic.
V
BAT
V
DD
During power-on initialization or power
supply voltage recovery after drop in clock
maintenance voltage
 Internal oscillation
(illustration)
FOUT
/RST
Figure 12 Power supply initial sequence

10.2. Precautions for power ON / OFF

1: To ensure that the power-on reset works at the initial power-on keep V
V = ON.
DD
2: Initial power-on tR1 is a necessary condition for enabling power-on reset.
If this condition is not satisfied, power-on reset may not work. As a result, the time accuracy and current consumption
may not meet the specifications. Please reset by software. See
3: When fluctuation of V
DD
oscillation, a set of VLF by V
4: The timing at which the I
V is turned on from backup mode.
DD
See the tCL and tCU specifications in the chart below.
5: These specifications don't mean a noise characteristic of a power supply of RTC.
Do not use amplitude signal output from a signal generator etc, as a power source.
RX8130CE
ETM50E-07
V detect voltage +V
DD
Minimum voltage for clock maintenance:
V
Min.
CLK
Oscillation start time
(internal oscillation wait time)
30ms
After 30 ms progress, Readout of VLF is possible.
At the time of VLF=1: After a t_str wait, initial setting is necessary.
At the time of VLF=0: Register access is possible.
However, clock updating is invalid while t_str.
is out of specifications, tF or tR2, it may be occur the followings, a momentary stop of crystal
voltage drop lower than V
OUT
2 C-Bus interface is enabled differs in when the initial power of V
Seiko Epson Corporation
10. Interface timing when power is turned ON / OFF
11
DET
t
Access is enabled
_str
Normal operation start
t
_DELAY_F
=V =GND for 10 seconds or more before
DD BAT
18.2 Software Reset.
and so on.
CLK
V Min.
CLK
t
_DELAY
is turned on and when
DD
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