TDA8745 Datasheet, PDF (15/40 Pages) NXP Semiconductors – Satellite sound receiver with I2C-bus control

Philips Semiconductors
Satellite sound receiver with I²C-bus control
Preliminary specification
TDA8745
Table 11 Bit TEST
TEST
s7
0
1
MODE
− (POR)
test
DESCRIPTION
in applications this bit should always be logic 0, to avoid conflicts with other settings
setting TEST enables some special modes used for factory testing
Table 12 Bit BB; baseband; note 1
BB
s6
MODE
DESCRIPTION
0
synthesizer synthesizer use (PLLs central frequency approximately 10.7 MHz) (after POR)
1
baseband baseband use (PLLs central frequency approximately 6 MHz)
Note
1. The PLL demodulators can also be used for demodulating FM carriers (e.g. terrestrial TV sound) at baseband
frequencies, by changing the lock range of the PLLs.
Table 13 Bits OS1 and OS0; output select; note 1
OS1
s5
0
0
1
1
OS0
s4
0
1
0
1
MODE
stereo (POR)
left
right
external
DESCRIPTION
Left channel audio (pin 33) at O_L; right channel audio (pin 31) at O_R
Left channel audio (pin 33) at both O_L and O_R
Right channel audio (pin 31) at both O_L and O_R
External left at (pin 25) at O_L; external right (pin 24) at O_R
Note
1. The signal at both line outputs O_L and O_R (pins 23 and 22) can be selected with bits OS1 and OS0.
Table 14 Bit PDM; Presence Detector auto Mute; note 1
PDM
s3
0
1
MODE
− (POR)
PDM
DESCRIPTION
−
if this bit is set to logic 1, a channel for which no incoming carrier is found will be muted
Note
1. In both situations the status of the presence detector can be monitored by reading the bits PDL (r7) and PDR (r6)
back from the IC. Appropriate action (e.g. muting, channel selection or tuning) can then be taken by the
microcontroller. Note that this function also mutes the signal from the external inputs (pins 25 and 24). This may be
desirable when using these inputs for connecting a satellite descrambler box. If not, reset PDM (s3) to logic 0 when
selecting external [e.g. together with bits OS1 (s5) and OS0 (s4)].
1996 Mar 11
15