MC44818 Просмотр технического описания (PDF) - Motorola => Freescale
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MC44818 Datasheet PDF : 8 Pages
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MC44818
Figure 2 shows the five bytes of information that are
needed for circuit operation: there is the chip address, two
bytes of control and band information and two bytes of
frequency information.
After the chip address, two or four data bytes may be
received: if three data bytes are received the third data byte
is ignored.
If five or more data bytes are received the fifth and
following data bytes are ignored and the last acknowledge
pulse is sent at the end of the fourth data byte.
The first and the third data bytes contain a function bit
which allows the IC to distinguish between frequency
information and control plus band information.
Frequency information is preceeded by a Logic “0”. If the
function bit is Logic “1” the two following bytes contain control
and band information. The first data byte, shifted after the
chip address, may be byte CO or byte FM.
The two permissible bus protocols with five bytes are
shown in Figure 2.
Figure 2. Definition of Bytes
CA_Chip Address
CO_Information
BA_Band Information
FM_Frequency Information
1
1
0
0
0
0/1
0/1
0
ACK
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ 1
T14
T13
T12
T11
T10
T9
T8
ACK
X
X
X
X
B3
B2
B1
B0
ACK
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ 0
N14
N13
N12
N11
N10
N9
N8
ACK
FL_Frequency Information
CA_Chip Address
FM_Frequency Information
FL_Frequency Information
CO_Information
N7
N6
N5
N4
N3
N2
N1
N0
ACK
ÉÉÉÉ1 ÉÉÉÉ1ÉÉÉÉÉÉ0 ÉÉÉÉ0ÉÉÉÉÉÉ0 ÉÉÉÉ0/1ÉÉÉÉ0ÉÉ/1 ÉÉÉÉ0ÉÉÉÉAÉÉCK ÉÉ
0
N14
N13
N12
N11
N10
N9
N7
N6
N5
N4
N3
N2
N1
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ 1
T14
T13
T12
T11
T10
T9
N8
ACK
N0
ACK
T8
ACK
BA_Band Information
X
X
X
X
B3
B2
B1
B0
ACK
Chip Address
The chip address is programmable by Pin 16 (AS –
Address Select).
AS – Pin 16
Gnd to 0.1 VCC1
Open or 0.2 VCC1 to 0.3 VCC1
0.4 VCC1 to 0.7 VCC1
0.8 VCC1 to 1.1 VCC1
Address (HEX.)
C0
C2
C4
C6
Bits B0, B1, B2, B3: Control the Band Buffers
B0, B1, B2, B3 = 0
B0, B1, B2, B3 = 1
Buffer “Off”
Buffer “On”
Figure 3. Equivalent Circuit of the Integrated
Band Buffers
25 V
Protection
IB
Gnd
ISUB
VCC3 12 V
“On”/“Off”
NOTE: IB + ISUB = 8.0 mA Typical, 13 mA Max
IB = Base Current
ISUB = Substrate Current of PNP
Out
B0…B3
30 mA (40 mA
at 0 to 80°C)
Bit T8: Controls the Output of the Operational Amplifier
T8 = 0
Normal Operation
Operational Amplifier Active
T8 = 1
Output State of Operational Amplifier Switched “Off”,
Output Pulls High Through 20 k Internal Pull–Up
Resistor
Bits T9, T12: Control the Phase Comparator
T9
T12
Function
1
0
Normal Operation
1
1
High Impedance
0
0
Upper Source “On” Only
0
1
Lower Source “On” Only
Bits T10, T11: Control the Reference Ratio
T10
T11
Division Ratio
0
0
512
0
1
1024
1
0
1024
1
1
512
Bit T13: Switches the Internal Signals Fref and FBY2 to
Bit T13: the Band Buffer Outputs (Test)
T13 = 0
T13 = 1
Normal Operation
Test Mode
Fref Output at B2 (Pin 12)
FBY2 Output at B3 (Pin 13)
Bits B2 and B3 have to be “On”, B2 = B3 = 1 in the test mode.
Fref is the reference frequency.
FBY2 is the output frequency of the programmable divider, divided by two.
4
MOTOROLA ANALOG IC DEVICE DATA
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