Bose Companion 5 Service Manual page 52

Companion 5 Audio Path
Signal Routing and Clocking
TDM Configuration
As mentioned section 2, the USB controller generates the two clocks required for transmitting the audio stream
via Time-Division Multiplex serial transmission. This is a scheme where all data between two points can be
transmitted over one data line. In Companion 5, separate data lines are used for different paths.
The frame sync, FCLK, is generated by the USB controller (U6000.35). This signal is high for the first bit (MSB)
of the first audio sample transmitted in each frame. The frame rate is set at 48kHz. Each of up to six audio
samples is transmitted in sequence followed by two null samples. Each audio sample is left-justified in a field of
32 bits. The eight total samples of 32 bits require a bit clock of 256 times the FCLK or 12.288MHz. This clock,
BCLK, is generated on pin U6000.37.
AUX Audio Input
The AUX stereo input from the control module is continuously converted and transmitted to the DSP via the TDM
data path, AD_DATA (U4000.9).
Slot Assignments for data from the Codec to the DSP are:
Audio Path (continued)
U6000
TAS1020
Controller
USB
TDMA in
TDMA out
U7000
TM320DA705
DSP
Time Slot
1
2
3
4
5
6
7
8
U4000
AK4626A
CODEC
ADC
DAC
X3
ANALOG STEREO
USB
TDMA, 8 slot: U6000 Provides Clock, Frame Sync
Audio Data
Left Aux
Right Aux
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
19
AUX IN
BASS1/BASS2
TO
LS/RS
POWER
AMP
LC/RC
U9100
NJM3414A
BUFFER
HEADPHONE
OUTPUT