We are currently using Murata 1MW module which uses CYW43455 chipset during evaluation for our next project.
We want to have the Bluetooth I2S bus connected directly to a DSP which will process 16-bit linear bluetooth audio data.
It is however not obvious, when reading the datasheet, if CYW43455 supports SBC-code mode for wideband speech and A2DP SBC-coded linear audio for the I2S bus/pins (not PCM-bus/pins) .
So I am trying to find answers to following questions:
- Can the module send 16-bit linear data (SBC decoded BT audio) over the I2S bus for HFP wideband?
- Can the module send 16-bit linear data (SBC decoded BT audio)over the I2S bus for A2DP 44.1kHz/48kHz?
- Can the module SBC-encode 16-bit linear BT audio data received over the I2S bus for HFP wideband?
Also, how is the I2S bus configured to be used for the bluetooth audio data? I assume that we need some vendor specific HCI commands for this? Where do we find such specification?
And regarding following snippet from datasheet:
■ 48 kHz x 32 bits per frame = 1.536 MHz
■ 48 kHz x 50 bits per frame = 2.400 MHz
The master clock is generated from the input reference clock using a N/M clock divider
How do we configure the master clock mentioned above?
Thanks in advance!
As per the datasheet, CYW43455 can perform SBC/mSBC encoding and decoding of wideband speechs or linear 16 bits at 16 kHz (256 Kbps rate) transferred over the PCM bus. PCM interface shares the pins with the I2S interfaces. So i think your first and third requirement can be satisfied. Let me check about the second requirement and implementation of it and get back to you..
Hi DheerajPK and thanks for your reply!
That sounds promising!
Please also notice my question regarding how the audio data is routed from the PCM to the I2S bus. I assume that I need some vendor specific HCI commands to accomplish this? This is applicable for both the A2DP and HFP use cases.
Hi @DheerajPK_41 , please let me know if you have update or pointers regarding the second requirement.
We are finalizing first round of evaluation hardware and it would really help to know if the second requirement could be fulfilled or not.