Espressif Systems ESP User Manual

Chapter 4. Software framework
4.1.41 What prole does ESP32’s classic Bluetooth® support?
• Currently, it supports A2DP, AVRCP, SPP, HFP, and HID.
4.1.42 How many stable connections can be reached for ESP32-C3’s Bluetooth® LE
(BLE)?
• We recommend the connection number does not exceed four.
4.1.43 How can I adjust the BLE advertising interval?
• The advertising interval is decided by adv_int_min and adv_int_max parameters in BLE advertising
struct, which con󰝘gures the minimum and maximum advertising interval respectively.
• The advertising interval ranges from 0x0020 to 0x4000 and the default value is 0x0800. The interval time is
the value * 0.625 ms, i.e., 20 ms to 10.24 sec.
• If the values of adv_int_min and adv_int_max are di󰝗erent, the advertising interval is within the range
of the two values. If the values are the same, the interval will be this 󰝘xed value.
4.1.44 How can I input the PIN code via mobile phone during ESP32’s Classic Bluetooth
Pairing mode?
You can disable Secure Simple Pairing to support only Legacy Pairing.
• From esp-idf v3.3 to v4.0 (not include v4.0): Component config > Bluetooth > Blue-
droid Enable > [*] Classic Bluetooth > [ ]Secure Simple Pairing
• esp-idf v4.0 and above:
Component config
>
Bluetooth
>
Bluedroid Options
>
[ ] Secure Simple Pairing
4.1.45 How much memory does ESP32 Bluetooth occupy?
• Controller:
– BLE single mode: 40 KB
– BR/EDR single mode: 65 KB
– Dual mode: 120 KB
• Main equipment:
– BLE GATT Client (Gatt Client demo): 24 KB (.bss+.data) + 23 KB (heap) = 47 KB
– BLE GATT Server (GATT Server demo): 23 KB (.bss+.data) + 23 KB (heap) = 46 KB
– BLE GATT Client & GATT Server: 24 KB (.bss+.data) + 24 KB (heap) = 48 KB
– SMP: 5 KB
– Classic Bluetooth (Classic Bluetooth A2DP_SINK demo, including
SMP/SDP/A2DP/AVRCP): 48 KB (.bss+.data) + 24 KB (heap) = 72 KB (an additional 13
KB is added when the example is running)
Note: The above heap (Heap) all include the task stack (Task Stack), because the task stack is allocated
from the heap and considered as a heap.
• Optimized PSRAM version:
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Espressif Systems ESP Specifications

General

Brand	Espressif Systems
Model	ESP
Category	Motherboard
Language	English