TDA8822 Datasheet, PDF (12/28 Pages) NXP Semiconductors – Universal I2C-bus programmable RF modulator

Philips Semiconductors
Universal I²C-bus programmable RF
modulator
Preliminary specification
TDA8822
Example of programming
We want to program the TDA8822 in a UHF application, on channel 21 (picture carrier at 471.25 MHz) in a B/G standard
(sound carrier at 5.5 MHz from the picture carrier) with a Picture-to-Sound ratio of −12 dB, a modulation depth of 82.5%
and a deviation set to 50.5% in normal mode, without TPSG, output port on.
These are the values of the bits that must be programmed:
• The video dividing ratio will be N = -f-_r--_e^f--o-_f--^s-_×--^c---8- = ^{4-7--7---81---1--2-2--5--.-5-0----}_×^0----0-8--0- = 7540 = 01110101110100
• TPSG bit will be set to logic 0
• DEV2 will be set to logic 0, DEV1 to logic 1 and DEV0 to logic 0
• PS2 will be set to logic 0, PS1 to logic 0 and PS0 to logic 1
• MD2 will be set to logic 1, MD1 to logic 0 and MD0 to logic 0
• SC1 will be set to logic 0 and SC0 to logic 1
• P0 will be set to logic 1
• RF0 will be set to logic 1
• T0 will be set to logic 0.
The protocol to the TDA8822 is illustrated in Table 10.
Table 10 Example of programming for the TDA8822.
BYTE
Address byte CA
F1: frequency
byte 1
F0: frequency
byte 0
C1: control byte 1
C0: Control byte 0
MSB
BIT 7
1
0
BIT 6
1
0
BIT 5
0
0
BIT 4
0
1
0
1
1
1
1
0
1
0
1
0
0
0
BIT 3
1
1
0
0
1
BIT 2
0
1
1
0
1
BIT 1
1
0
0
1
1
LSB
BIT 0
0
1
0
0
0
ACKNOWLEDGE
ACK
ACK
ACK
ACK
ACK
1997 Jan 08
12