mc44871 Freescale Semiconductor, Inc, mc44871 Datasheet - Page 7

• Manufacturer Part Number: mc44871
• Description: Tuning Circuit With High Speed Tuning Supply
• Manufacturer: Freescale Semiconductor, Inc

I 2 C Write Mode Format and Bus Receiver
byte followed by two or four data bytes, is treated in the I 2 C
bus receiver. The definition of the permissible bus protocol is
shown below:
1_STA CA
2_STA CA
3_STA CA
4_STA CA
STA = Start Condition
CA = Chip Address Byte
CO = Control Information
BA = Band Information
FM = Frequency Information with MSB
FL = Frequency Information with LSB
STO = Stop Condition
needed for circuit operation: the chip address, two bytes of
control and information, and two bytes of frequency
information.
received: if three data bytes are received, the third one is
MOTOROLA ANALOG IC DEVICE DATA
The incoming information, consisting of a chip address
Figure 5 shows the five bytes of information that are
After the chip address, two or four data bytes may be
SDA
SCL
STA
CO
FM
CO
FM
1
BA
FL
BA
FL
2
FM
CO
STO
STO
Chip Address ($C2)
3
FL
BA
4
Figure 5. High Speed I 2 C Compatible Bus Data Format
5
STO
STO
6
7
8
ACK
9
MC44871
10
First Byte
ignored. If five or more data bytes are received, the fifth and
following ones are ignored, and the last acknowledge pulse is
sent at the end of the fourth data byte.
which allows the IC to distinguish between frequency
information and control plus band information. If the function
bit is logic “1”, the two following bytes contain control and
band information. The first data byte, after the chip address,
may be byte CO or byte FM. The two bytes of frequency
information are preceeded by a logic “0”.
Chip Address
are for read mode. Chip address is programmable by Pin 12
(ADD).
The first and the third data bytes contain a function bit
Even addresses are for write mode, and odd addresses
0.2 V CC to 0.3 V CC (or Open)
–0.01 V CC to 0.1 V CC
0.4 V CC to 0.7 V CC
0.8 V CC to 1.1 V CC
2 or 4 Data Bytes
ADD Pin 12
ACK
18
19
ACK
Address (HEX.)
C0/C1
C2/C3
C4/C5
C6/C7
Stop
7