AIROC™ Bluetooth® system on chip for automotive applications
Peripherals
7.10.2
Frame synchronization
The CYW89820 supports both short- and long-frame synchronization in both master and slave modes. In short
frame synchronization mode, the frame synchronization signal is an active-high pulse at the audio frame rate that
is a single-bit period in width and is synchronized to the rising edge of the bit clock. The PCGM slave looks for a
high on the falling edge of the bit clock and expects the first bit of the first slot to start at the next rising edge of
the clock. In long-frame synchronization mode, the frame synchronization signal is again an active-high pulse at
the audio frame rate; however, the duration is three bit periods and the pulse starts coincident with the first bit
of the first slot.
7.10.3
Data formatting
The CYW89820 may be configured to generate and accept several different data formats. For conventional narrow
band speech mode, the CYW89820 uses 13 of the 16 bits in each PCM frame. The location and order of these 13
bits can be configured to support various data formats on the PCM interface. The remaining three bits are ignored
on the input and may be filled with 0s, 1s, a sign bit, or a programmed value on the output. The default format is
13-bit 2’s complement data, left justified, and clocked MSB first.
Datasheet
20
002-25826 Rev. *G
2022-09-24