Hi everyone,

I’m looking for help identifying a Bluetooth module/chipset for an embedded hands-free voice project.

The requirement is specific:

I need a Bluetooth module/chipset that can operate as a Hands-Free device and transmit externally supplied digital audio as the HFP/SCO/eSCO microphone uplink to a phone.

Minimum voice quality target:

• HFP wideband speech / mSBC
• Better is welcome, but only if it applies to hands-free call uplink, not music streaming

Acceptable digital input paths could be:

• PCM
• I2S
• TDM
• SCO/eSCO PCM pins
• External codec interface
• HCI SCO audio, if practical

I'm not looking for analog microphone input into the Bluetooth module, nor am I looking for a generic Bluetooth audio/A2DP module. I specifically need proof that the external digital audio input can be used as the microphone source for HFP/SCO/eSCO uplink.

For example, a module saying “HFP supported” and “I2S supported” separately is not enough. I need the documentation, firmware, SDK, or known working example to explicitly show that digital audio can feed the HFP microphone/uplink path.

My previous candidate was Microchip BM83 / IS2083, but I could not find clear documentation proving that external I2S/DR1 audio can be routed into the HFP/SCO uplink encoder. The documented safe paths appeared to be analog mic or PDM mic, which does not solve my use case.

Ideal solution:

• Low-cost / practical module or chipset
• HFP Hands-Free role
• mSBC / WBS support minimum
• Digital voice input for HFP uplink
• MCU control via UART, USB, HCI, AT commands, SPI, I2C, or similar
• Call-state events available to MCU if possible
• Firmware/configuration tools realistically accessible to an individual developer

I’m especially interested in leads involving:

• Qualcomm / CSR / BlueCore / QCC modules
• Older HFP modules exposing SCO PCM pins
• Modules intended for external audio codecs
• Open-source or low-cost host-stack approaches
• Any known working module where PCM/I2S/SCO digital audio is confirmed to feed HFP uplink

Does anyone know of a module, chipset, SDK, firmware stack, or reference design that actually supports this?

Thanks.

 

Quick update for anyone looking for the same thing:

I ended up finding a module that appears to support this exact use case: IOT747 IDC777 / IDC767 with AudioAgent AA32xx firmware.

I contacted IOT747 support directly and they confirmed that with digital audio enabled, the module can route external digital audio through the Bluetooth audio path, including HFP with mSBC/WBS. In my case, the intended path is:

external DSP / codec → I2S/PCM into IDC767 → HFP/SCO/eSCO microphone uplink to phone

They also confirmed the same family supports digital output for far-end audio, and that internal echo cancellation can be disabled/minimized through configuration.

I rejected a few other modules because “HFP supported” + “I2S supported” was not enough; the missing proof was whether I2S/PCM could actually feed the HFP microphone uplink path. Feasycom, for example, confirmed that one suggested module would require custom firmware for this exact use case.

So for anyone searching later: look specifically at IOT747 IDC777/IDC767 + AudioAgent, and ask the vendor to confirm the exact HFP digital-uplink routing for your firmware build.