csr8510 bluetooth controller

[Nikolas]

Hi,

I'm looking for a solution to use the BTStack+MCU with a BT controller.

I'm having a look at esp32 but seems that it needs firmware loaded(customised) and makes it a bit problematic when in production.

Will something like this work: https://www.qualcomm.com/products/csr8510/documentation

Use SCO data for audio over the UART?

Thanks

[Matthias Ringwald]

Hi Nikolas

The CSR8510 is in the majority of USB Bluetooth dongles sold in the last years. It works well and SCO is send over USB Isochronous Endpoints (as described in the Bluetooth Core Specification).

Its sibling, the CSR8511 has a UART interface which is easier to use with a microcontroller. We don't know how to send SCO packets over UART with CSR/Qualcomm.
If you only need 8kHz, you can connect it's PCM/I2S directly. For Wide-band speech, you can connect the PCM/I2S to your MCU where the mSBC data is then decoded.

A simpler approach can be the TI CC2564C, where SCO over UART works flawless, all audio (incl. mSBC from HFP) is then available on the MCU.
Or, you can use e.g. the CYW20704 which provides an mSBC codec on the Controller, such that you have 8/16 kHz audio directly on the Controllers PCM/I2S pins.

If this is for a commercial product, feel free to contact us on con...@bluekitchen-gmbh.com

Best
Matthias

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[Nikolas]

Hi,

Thank you for the reply.

The MCU will provide the I2S/PCM audio.

I was looking at the SCO data for audio as an alternative for esp32 as the I2S/PCM needs to be enabled by software and doesn't work like the TI CC2564C that does by default.

The TI would be a good choice but due to supply availability only a few options are available.

I also have a FC20/FC21 module as a candidate (from Quectel). They use the following chipset: 

https://www.qualcomm.com/products/qca9377

Perhaps this maybe a suitable candidate?

Nikolas

[Nikolas]

Hi,

This one can perhaps be evaluated:

https://www.digikey.com.au/en/products/detail/dialog-semiconductor-gmbh/DA14531-00000FX2/10474881

Cost effective and in supply.

Nikolas

[Matthias Ringwald]

Hi NIkolas

If you want/need HFP Wide-Band, generally there are three options:
- the Controller supports SCO over HCI and also provides a working SCO Flow control for sending. Then mSBC data can be decoded on the MCU. Here, only the TI CC 2564C (and a Realtek Bluetooth/Wifi Controller) support this as well as the ESP32 via the internal VHCI do this. Again, I don't know if SCO can be used over the external HCI interface. Might be worth a try.
- the Controller can be configured to decoded mSBC audio and provide it via its PCM/I2S interface to the MCU or a DSP. This works with newer Broadcom/Cypress/Infineon Controllers like the CYW20704.
- the mSBC data is sent over PCM/I2S to the MCU, where it is decoded to actual PCM so it can be used on a second I2S MCU interface.

CSR Controller probably can decode mSBC as well, but there is no public documentation/examples on how to configure that.

Best
Matthias

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