High Speed I2C Compatible Bus

MC44BS374T1/374T1A Advance Information

After the chip address, two or four data bytes may be received.

•

If three data bytes are received, the third one is ignored.

•

If five or more data bytes are received, the fifth and following ones are ignored, and the last ACK

pulse is sent at the end of the fourth data byte.

The first and third data bytes contain a function bit, which lets the IC distinguish between frequency

information and control information. If the function bit is a logic 1, the two following bytes contain control

information. The first data byte after the chip address, may be byte CO or byte FM. The two bytes of

frequency information are preceded by a logic 0.

The incoming information consists of the read mode chip address byte. The device then answers with an

ACK followed by one byte containing three bits of status information. No acknowledge is answered by the

modulator after this byte.

FM = Frequency information, high order bits

FL = Frequency information, low order bits

C1 = Control information, high order bits

CO = Control information, low order bits

STO = Stop condition

1 1 0 0 1 0 1 1 (ACK) = $CB (hex) in read mode

Table 10. Permitted Data Bytes (Incoming Information)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com