TDA1315 Philips Semiconductors, TDA1315 Datasheet - Page 8

• Manufacturer Part Number: TDA1315
• Description: Digital audio input/output circuit DAIO
• Manufacturer: Philips Semiconductors

B
In the biphase modulator section, audio and non-audio
data are combined into subframes, frames and blocks, and
encoded in the biphase-mark format during transmit mode.
Although there are always 24 audio bits per sample in a
subframe, the number of significant bits can be selected as
16, 18, 20 or 24 via the control register (host mode).
A
In the audio section, the left and right channel audio
samples are taken from the demodulated data frames and
are output serially in accordance with the I
(for details see Chapter “References”[3] pins SD, SCK and
WS) when the TDA1315H is in the receive mode (I
transmitter). The audio output signals are concealed or
muted in case certain errors were detected during
reception. Mute can be enforced by pin MUTE or via the
control register (host mode) and affects, depending on the
receive/transmit mode, the I
MUTE is internally synchronized with the audio data. In the
transmit mode, there is an additional I
SDAUX made available to accept audio data from, for
example, an ADC. This input can be selected either by pin
I
can be enabled/disabled by pin I
register or both. In the transmit mode, I
timing are supplied by an external source, the TDA1315H
then becomes an I
of an I
output at IECO. Although the phase relationship between
system clock (SYSCLKI) and I
critical they must be synchronous with each other, i.e. be
derived from the same source.
Receive mode
The IEC subframe format defines 20 bits for an audio
sample, plus 4 auxiliary bits, which can be used to extend
the word length. By default, all 24 data bits per sample are
output via the I
however, to 16, 18 or 20 bits via bits 2 and 3 in byte 1 of
the control register. The remaining bits will then be zero.
The serial audio clock frequency at pin SCK is 64
there are 32 clock pulses per audio sample (left or right
channel).
2
IPHASE DEMODULATOR
UDIO SECTION
SSEL, by the control register or both. The I
Philips Semiconductors
1995 Jul 17
Digital audio input/output circuit (DAIO)
2
S-bus source determines which signal is to be
2
S-bus Port. This can be changed,
2
S-bus receiver. In this event, selection
2
S-bus or IEC output signals.
2
S timing (SCK) is not
2
SOEN, by the control
2
S-bus data input
2
S-bus data and
2
S-bus format
2
S-bus Port
2
S-bus
f
s
, i.e.
8
Apart from detecting the out-of-lock condition of the PLL,
received data is checked for the errors listed below. All
detected errors will be flagged in the status register and
two of them brought out to a pin. Depending on the type of
error, different measures are taken.
In the receive mode it is possible to select the auxiliary
I
there will be no suitable system clock available in the event
of an open IEC input or a disabled IEC source and output
SD will be muted when the TDA1315H is not in lock.
Regardless of which source is selected, a MUTE
command will always mute the output signal at pin SD and
set the INVALID output to LOW regardless of the validity
bit value. When mute command is disabled, muting will be
released when the outputting of the next stereo sample
begins.
2
S-bus data input SDAUX for output at pin SD. However,
Validity flag set. This error condition is also output at pin
INVALID, simultaneously with the data. The
corresponding audio sample is not modified.
Parity check error. A concealment operation is
performed on both audio channels (left and right), i.e.
the last correctly received stereo sample is output again.
Biphase violation (other than preambles). A
concealment operation (hold) is performed on both
audio channels (left and right), i.e. the last correctly
received stereo sample is output again.
PLL is out-of-lock. This error condition is also output at
pin UNLOCK. Both audio output channels (left and right)
are set to zero (mute). The error condition is sampled
with the HIGH-to-LOW transition of WS, i.e. muting
becomes effective when the outputting of a stereo
sample begins. When the PLL has locked again, muting
is released only after a full block of audio samples has
been received, free of errors.The INVALID output will
always be set to LOW simultaneously with this muting.
Product specification
TDA1315H