TDA9874A Philips Semiconductors, TDA9874A Datasheet - Page 51

• Manufacturer Part Number: TDA9874A
• Description: Digital TV sound demodulator/decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
10.4
As a slave transmitter, the TDA9874A provides 12 registers with status information and data, a part of which is for Philips
internal purposes only. Each register is accessed by means of a subaddress.
Detailed descriptions of the slave transmitter registers are given in Sections 10.4.1 to 10.4.9.
Reading of data can start at any valid subaddress. It is allowed to read more than 1 data byte per transmission from the
TDA9874A. In this case, the subaddress is automatically incremented after each data byte, resulting in reading the
sequence of data bytes from successive register locations, starting at SUBADDRESS.
Each data byte in a read sequence, except for the last one, is acknowledged with Am. The subaddresses ‘wrap around’
from decimal 255 to 0. If an attempt is made to read from a non-existing subaddress, the device will send a data pattern
of all ones, i.e. FF in hexadecimal notation.
Table 71 General format for reading data from the TDA9874A
Table 72 Explanation of Tables 71 and 73
Table 73 Format of a transmission using automatic incrementing of subaddresses
1999 Dec 03
S SLAVE ADDRESS 0 A SUBADDRESS A Sr SLAVE ADDRESS 1 A
S
SLAVE ADDRESS
0
A
SUBADDRESS
Sr
1
DATA
NAm
Am
P
S SLAVE ADDRESS 0 A SUBADDRESS A Sr SLAVE ADDRESS 1 A DATA BYTE Am
Digital TV sound demodulator/decoder
Slave transmitter mode
BIT
START condition
7-bit device address
data direction bit (write to device)
acknowledge (by the slave)
address of register to read from
repeated START condition
data direction bit (read from device)
data byte read from register
not acknowledge (by the master)
acknowledge (by the master)
STOP condition
51
FUNCTION
n data bytes with
of subaddresses
auto-increment
DATA
Preliminary specification
TDA9874A
DATA NAm P
NAm P