TDA9874A Philips Semiconductors, TDA9874A Datasheet - Page 25

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

Philips Semiconductors
10.3
As a slave receiver, the TDA9874A provides 26 registers
for storing commands and data. Each register is accessed
via a so-called subaddress. A subaddress can be thought
of as a pointer to an internal memory location.
Detailed descriptions of the slave receiver registers are
given in Sections 10.3.2 to 10.3.21.
It is allowed to send more than one data byte per
transmission to the TDA9874A. In this event, the
subaddress is automatically incremented after each data
byte, resulting in storing the sequence of data bytes at
successive register locations, starting at SUBADDRESS.
A transmission can start at any valid subaddress. Each
byte that is properly stored, is acknowledged with A
(acknowledge). If an attempt is made to write data to a
non-existing subaddress, the device acknowledges with
NA (not acknowledge), therefore telling the I
to abort the transmission. There is no ‘wrap-around’ of
subaddresses.
Table 9 I
Table 10 Explanation of Table 9
Table 11 Format for a transmission employing auto-increment of subaddresses
10.3.1
The TDA9874A can be programmed in the same way as its predecessor (TDA9874H) using the subaddresses 0 to 24
or by using ESP.
1999 Dec 03
S
SLAVE ADDRESS
0
A
SUBADDRESS
DATA
A/NA
P
S
S
Digital TV sound demodulator/decoder
SLAVE ADDRESS
SLAVE ADDRESS
Slave receiver mode
P
2
ROGRAMMING VIA THE
C-bus; slave address/subaddress/data format
BIT
0 A
0 A
I
2
C-
SUBADDRESS
SUBADDRESS
BUS
2
C-bus master
START condition
7-bit device address
data direction bit (write to device)
acknowledge
address of register to write to
data byte to be written into register
acknowledge or not acknowledge
STOP condition
A
A
25
n data bytes with auto-increment of
Commands and data will be processed as soon as they
have been received completely. Functions requiring more
than one byte will thus be executed only after all bytes for
that function have been received. If the transmission is
terminated (STOP condition) before all bytes have been
received, the incomplete data for that function is ignored.
Data patterns sent to the various subaddresses are not
checked for being illegal or not at that address, except for
the level adjustment functions.
Detection of a STOP condition without a preceding
acknowledge bit is regarded as a bus error. In this case,
the last operation will not be executed.
DATA BYTE A
subaddresses
DATA
FUNCTION
Preliminary specification
DATA
TDA9874A
A/NA
A/NA
P
P