Philips CEM5000/00, Service Manual

Page: 51 / 83

TDA7419
20/30
6 I
2
C BUS SPECIFICATION
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 = Start
R/W = "0" -> Receive Mode (Chip can be programmed by
µ
P)
"1" -> Transmission Mode (Data could be received by
µ
P)
ACK = Acknowledge
P = Stop
TS = Testing mode
AZ = Auto zero remain
AI = Auto increment
6.1.2 Transmission Mode
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:
S 1 0 0 0 1 0 0 R/W ACK TS AZ AI A4 A3 A2 A1 A0 ACK DATA ACK P
S 1 0 0 0 1 0 0 R/W ACK X X X X X X X SM ACK P
MSB LSB
1 1 1 1 1 1 1 0