S-35770E01A-K8T2U Datasheet, PDF (18/26 Pages) Seiko Instruments Inc – CONVENIENCE TIMER

FOR AUTOMOTIVE 125°C OPERATION 2-WIRE COUNTER CONVENIENCE TIMER
S-35770 Series
Rev.1.2_00
7. Read operation of free register
Perform the read operation of the free register with the restart format. Regarding the restart format, refer to
"4. Data transmission format".
Transmit the start condition and the slave address from the master device. The slave address of the S-35770 Series is
specified to "0110010". Next, transmit "0" to the read / write bit.
B7 in the 2nd byte is an address pointer. Set B7 to "0" when reading the free register. Next, transmit the dummy data to
B6 to B1. Make sure to set B0 to "1" since it is a test bit. This processing is called "dummy write".
Then transmit the start condition, the slave address and the read / write bit. If the read / write bit is set to "1", the
S-35770 Series becomes the mode to read the free register.
Consequently, the data of the free register is output from the S-35770 Series. Each byte from B7 is transmitted.
When the read operation of the free register is finished, transmit "1" (NO_ACK) to the acknowledge after B0 output
from the master device, and then transmit the stop condition.
The free register is a 3-byte register. "1" is read if the read operation is performed continuously after reading 3 bytes of
the free register.
Regarding the free register, refer to " Configuration of Registers".
Moreover, the internal address pointer is reset if recognizing the stop condition. Therefore, do not transmit the stop
condition after dummy write operation. The counter data is read when reading the free register after transmission of
the stop condition.
Disable time period of count-up action
1
9
SCL
18
1
9
18
27
36
SDA
01100100 0
1
01100101
B7
B1R/W B7
B0
B7
B1R/W B7
Slave address
(0110010)
Dummy data^*1
Slave address
(0110010)
Make sure to set B0 to "1" since it is a test bit.
Set B7 as an address pointer.
B0 B7
B0 B7
B0
Free register (3-byte)
Input NO_ACK
after
the 3rd byte transmission.
Dummy write
: _{Master device input data}
: _{S-35770 output data}
*1. Set B6 to B1 to "0" or "1" since they are dummy data.
Figure 24 Read Timing of Free Register
18