Bluetooth
Bluetooth is a wireless technology standard for exchanging data over short distances, with advantages including robustness, low power consumption and low cost. The Bluetooth system can be divided into two different categories: Classic Bluetooth and Bluetooth Low Energy (BLE). ESP32 supports dual-mode Bluetooth, meaning that both Classic Bluetooth and BLE are supported by ESP32. It operaters at 2.4GHz.
Bluetooth Radio and Baseband
The Bluetooth Radio and Baseband support the following features: • Class-1, class-2 and class-3 transmit output powers, and a dynamic control range of up to 24 dB • π/4 DQPSK and 8 DPSK modulation • High performance in NZIF receiver sensitivity with over 94 dBm of dynamic range
• Class-1 operation without external PA • Internal SRAM allows full-speed data-transfer, mixed voice and data, and full piconet operation • Logic for forward error correction, header error control, access code correlation, CRC, demodulation, encryption bit stream generation, whitening and transmit pulse shaping • ACL, SCO, eSCO and AFH • A-law, µ-law and CVSD digital audio CODEC in PCM interface • SBC audio CODEC • Power management for low-power applications • SMP with 128-bit AES
Bluetooth Interface
• Provides UART HCI interface, up to 4 Mbps • Provides SDIO / SPI HCI interface • Provides PCM / I²S audio interface
Bluetooth Stack
The Bluetooth stack of the chip is compliant with the Bluetooth v4.2 BR/EDR and Bluetooth LE specifications.
Piconet and Scatternet
Device supports both Piconet and Scatternet.
Bluetooth Profiles
Bluetooth profiles are additional protocols that build upon the basic Bluetooth standard to more clearly define what kind of data a Bluetooth module is transmitting. While Bluetooth specifications define how the technology works, profiles define how it's used.
The profile(s) a Bluetooth device supports determine(s) what application it's geared towards. A hands-free Bluetooth headset, for example, would use headset profile (HSP), while a Nintendo Wii Controller would implement the human interface device (HID) profile. For two Bluetooth devices to be compatible, they must support the same profiles.
Few of the more commonly-encountered Bluetooth profiles:-
- Serial Port Profile (SPP)
- Human Interface Device (HID)
- Hands-Free Profile (HFP) and Headset Profile (HSP)
- Advanced Audio Distribution Profile (A2DP)
- A/V Remote Control Profile (AVRCP)