DS4000 Dallas Semiconducotr, DS4000 Datasheet - Page 12

• Manufacturer Part Number: DS4000
• Description: Digitally Controlled TCXO
• Manufacturer: Dallas Semiconducotr

Figure 3. Data Transfer On 2-Wire Serial Bus
DATA TRANSFER
Figures 4 and 5 detail how data transfer is accomplished on the 2-wire bus.
Depending on the R/ W bit in the transmission protocols as shown, two types of data transfer are possible:
1) Data transfer from a master transmitter to a slave receiver. The first byte transmitted by the master is the
2) Data transfer from a slave transmitter to a master receiver. The master transmits the first byte (the slave
SDA
SCL
slave address. Next follows a number of data bytes. The slave returns an acknowledge bit after each received
byte. Data is transferred with the most significant bit (MSB) first.
address). The slave then returns an acknowledge bit. Next follows a number of data bytes transmitted by the
slave to the master. The master returns an acknowledge bit after all received bytes other than the last byte. At
the end of the last received byte, a “not acknowledge” is returned. The master device generates all of the serial
clock pulses and the START and STOP conditions. A transfer is ended with a STOP condition or with a
repeated START condition. Since a repeated START condition is also the beginning of the next serial transfer,
the bus is not released.
CONDITION
START
MSB
1
2
ADDRESS
SLAVE
3-5
6
7
R/W BIT
8
12 of 16
ACK
9
ACKNOWLEDGEMENT
SIGNAL FROM
RECEIVER
1
2
MORE BYTES ARE
TRANSFERRED
REPEATED IF
3-7
ACKNOWLEDGEMENT
8
SIGNAL FROM
RECEIVER
ACK
9
START CONDITION
STOP CONDITION
OR REPEATED