S-35770E01A-K8T2U Datasheet, PDF (19/26 Pages) Seiko Instruments Inc – CONVENIENCE TIMER

Rev.1.2_00
FOR AUTOMOTIVE 125°C OPERATION 2-WIRE COUNTER CONVENIENCE TIMER
S-35770 Series
 Release of SDA
_______
The RST pin of the S-35770 Series does not perform the reset operation of the communication interface. Therefore,
the stop condition is input to reset the internal interface circuit usually.
However, the S-35770 Series does not accept the stop condition from the master device when in the status that SDA
outputs "L" (at the time of acknowledge outputting or reading). Consequently, it is necessary to finish the acknowledge
output or the read operation. Figure 25 shows the SDA release method.
First, input the start condition from the master device (since SDA of the S-35770 Series outputs "L", the S-35770 Series
can not detect the start condition). Next, input the clocks for 1-byte data access (9 clocks) from SCL. During the time,
release SDA of the master device. By this, the SDA input / output before communication interrupt is completed, and
SDA of the S-35770 Series becomes release status. Continuously, if the stop condition is input, the internal circuit
resets and the communication returns to normal status.
It is strongly recommended that the SDA release method is performed at the time of system initialization after the power
supply voltage of the master device rises.
Start condition
SCL
Clocks for 1-byte data access
Stop condition
12
8
9
SDA
(Master device output)
SDA
(S-35770 output)
"L"
"L"
SDA
"L" or High-Z
"L" or High-Z
High-Z
Figure 25 SDA Release Method
 Power-on Detection Circuit
In order for the power-on detection circuit to operate normally, raise the power supply voltage of the IC from 0.2 V or lower
so that it reaches 1.5 V of the operation power supply voltage minimum value within 10 ms, as shown in Figure 26.
Within 10 ms
1.5 V
(Operation power
supply voltage min.)
0.2 V or lower
0 V^*1
*1. 0 V means that there is no potential difference between the VDD pin and the VSS pin of the S-35770 Series.
Figure 26 How to Raise the Power Supply Voltage
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