SC7315

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.0

2004.08.03

Http: www.silan.com.cn

Page 7 of 13

APPLICATION NOTES

Data transmission from microprocessor to the SC7315 and viceversa takes place through the 2 wires I

interface, consisting of the two lines SDA and SCL(pull-up resistors to positive supply voltage must be

connected).

2. DATA VALIDITY

As shown in Figure 17, the data of the SDA line must be stable during the high period of the clock. The HIGH

and LOW state of the dtat line can only change when the clock signal on the SCL line is LOW.

Fig. 17 Data Validity on the I

3. START AND STOP CONDITIONS

As shown in Figure 18, a start condition is a HIGH to LOW transition of the SDA line while SCL is HIGH. The

stop condition is a LOW to HIGH transition of the SDA line while SCL is HIGH.

Fig. 18 Timing diagram of I2C BUS

4. BYTE FORMAT

Every byte transferred on the SDA line must obtain 8 bits. Each byte must be followed by the an acknowledge

bit. The MSB is transferred first.

5. ACKNOWLEDGE

The master(microprocessor) puts a resistive HIGH level on the SDA line during the acknowledge clock

pulse(see Figure 19). The peripheral(audioprocessor) that acknowledges has to pull-down(LOW) the SDA line

during the acknowledge clock pulse, so that the SDA line is stable LOW during this clock pulse.

The audioprocessor which has been addressed has to generate an acknowledge after the reception of each

byte , otherwise the SDA line remain at the HIGH level during the ninth clock pulse time. In this case the master

transmitter can generate the STOP information in order to abort the transfer.