TDA8722 Philips Semiconductors, TDA8722 Datasheet - Page 7

• Manufacturer Part Number: TDA8722
• Description: I2C-bus programmable modulator for negative video modulation and FM sound
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Table 1 Data format; notes 1 and 2
Notes
1. The 10 programmable bits of N are: b2 to b11.
2. Internal hardware sets: b1 = 0 and b0 = 1.
3. T0, T1 and T2 are bits used for test purposes (see Table 5).
4. P0 is a bit used for controlling the state of the output Port (see Table 6).
Table 2 Structure of the dividing number N
Notes
1. Bits b2 to b11 are programmable and represent the integer part of the frequency in MHz. Bits b1 and b0 are fixed
2. Bits b1 and b0 are not programmable.
3. f
Table 3 Dividing number N for programming channel 21 (471.25 MHz)
Notes
1. Bits b1 and b0 are not programmable.
2. f
Table 4 Content of the data bytes to program channel 21 (471.25 MHz)
It is possible to change only one data byte. The circuit will recognize which one is received with the value of MSB
(0 for data byte 1 and 1 for data byte 2). It is possible to change the frequency by 1 MHz with data byte 2. It is easy to
increment the channel frequency when its frequency width is 8 MHz by simply incrementing data byte 1.
1998 Jun 23
Address byte C8
Data byte 1
Data byte 2
Frequency (MHz)
Value
Frequency (MHz)
Address byte C8
Data byte 1
Data byte 2
I
negative video modulation and FM sound
2
internally to b1 = 0 and b0 = 1 to get the added 0.25 MHz, common for most TV channels.
osc
osc
C-bus programmable modulator for
RESULT
RESULT
BYTE
= 512b11 + 256b10 + 128b9 + 64b8 + 32b7 + 16b6 + 8b5 + 4b4 + 2b3 + b2 + 0.25 (MHz).
= 0 + 256 + 128 + 64 + 0 + 16 + 0 + 4 + 2 + 1 + 0.25 (MHz) = 471.25 MHz.
BYTE
(3)
(2)
BIT 7
BIT 7
MSB
MSB
b11
512
b11
0
0
1
0
1
1
0
1
b10
b10
256
256
BIT 6
BIT 6
T0
1
b11
1
1
0
0
(3)
128
128
b9
b9
1
BIT 5
BIT 5
T1
b10
0
0
1
0
(3)
b8
b8
64
64
1
BIT 4
BIT 4
T2
b9
0
0
1
0
(3)
b7
32
b7
0
0
7
BIT 3
BIT 3
P0
b8
1
1
1
0
(4)
b6
b6
16
16
1
BITS
BITS
BIT 2
BIT 2
b7
b4
0
0
0
1
(1)
b5
b5
8
0
0
BIT 1
BIT 1
b6
b3
0
0
1
1
b4
b4
4
1
4
BIT 0
BIT 0
LSB
LSB
b5
b2
0
b3
b3
0
0
1
2
1
2
ACKNOWLEDGE BIT
ACKNOWLEDGE BIT
b2
b2
Product specification
1
1
1
TDA8722
ACK
ACK
ACK
ACK
ACK
ACK
b1
b1
0.5
0
0
(2)
(1)
b0
b0
0.25
0.25
1
(2)
(1)