Philips CEM5000/00 Service Manual page 51

TDA7419
6 I C BUS SPECIFICATION
2
6.1 Interface Protocol
The interface protocol comprises:
– a start condition (S)
– a chip address byte (the LSB determines read/write transmission)
– a subaddress byte
– a sequence of data (N-bytes + acknowledge)
– a stop condition (P)
– the max. clock speed is 500kbits/s
– 3.3V logic compatible
6.1.1 Receive Mode
S 1 0 0 0 1
S = Start
"0" -> Receive Mode (Chip can be programmed by µP)
R/W =
"1" -> Transmission Mode (Data could be received by µP)
ACK = Acknowledge
P = Stop
TS = Testing mode
AZ = Auto zero remain
AI = Auto increment
6.1.2 Transmission Mode
S 1 0 0 0 1
SM = Soft mute activated for main channel
X = Not Used
The transmitted data is automatic updated after each ACK. Transmission can be repeated without new
chip address.
6.1.3 Reset Condition
A Power-On-Reset is invoked if the Supply-Voltage is below than 3.5V. After that the following data is writ-
ten automatically into the registers of all subaddresses:
20/30
0 0 R/W ACK TS
0 0 R/W ACK
MSB
1 1 1
AZ AI A4 A3
X X X X X
1 1 1
A2 A1 A0 ACK DATA
X X SM ACK P
LSB
1 0
ACK P