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Based on British CSR BlueCore4-Ext chip, follow V2.1 + EDR Bluetooth specification. The module supports UART, USB, SPI, PCM, SPDIF interface, and support for the SPP Bluetooth serial protocol, low cost, small size, low power consumption, send and receive sensitivity advantages, just with a few external components will be able to achieve its powerful. Feature:

  • Bluetooth V2.1 + EDR
  • Bluetooth Class 2
  • Built-in PCB RF antenna
  • Built-in 8Mbit Flash
  • Support for SPI programming interface
  • Support UART, USB, SPI, PCM interface
  • 3.3V power supply
  • REACH, ROHS certification

Application: The module is mainly used for short-range wireless data transmission field. Convenient and connected to the PC, Bluetooth devices can also data exchange between the two modules. Avoid cumbersome cable connections, direct replacement for the serial line.

  • Bluetooth wireless data transmission;
  • industrial remote control, telemetry;
  • POS system, wireless keyboard, mouse;
  • traffic, underground positioning, alarm;
  • automated data acquisition system;
  • wireless data transmission; banking system;
  • wireless data acquisition;
  • building automation, security, wireless monitoring room equipment, access control systems;
  • smart home, industrial control;
  • automotive testing equipment;
  • television the interactive program vote Equipment;
  • government street light energy saving equipment
  • wireless LED display system
  • Bluetooth joystick, Bluetooth gamepad
  • Bluetooth printer
  • Bluetooth remote control toy

Mechanical Features:

  • Operating Frequency Band 2.4GHz -2.48GHz unlicensed ISM band
  • Bluetooth Specification V2.1+EDR
  • Output Power Class Class 2
  • Operating Voltage 3.3V
  • Host Interface USB 1.1/2.0 or UART
  • Audio Interface PCM interface
  • Flash Memory Size 8Mbit
  • Dimension 27mm (L) x 13 (W) mm x 2mm (H)

Electric Features:

  • Absolute Maximum Ratings
  • Rating Min Max
  • Storage temperature -40℃ +150℃
  • Supply voltage: VBAT -0.4V 5.6V
  • Other terminal voltages VSS-0.4V VDD+0.4V

  • Recommended Operating Conditions
  • Operating Condition Min Max
  • Operating temperature range -40℃ +150℃
  • Guaranteed RF performance range(a) -40℃ +150℃
  • Supply voltage: VBAT 2.2V 4.2V(b)

Power Consumption:

  • Operation Mode Connection Type UART Rate(kbps) Average Unit
  • Page scan - 115.2 0.42 mA
  • ACL No traffic Master 115.2 4.60 mA
  • ACL With file transfer Master 115.2 10.3 mA
  • ACL 1.28s sniff Master 38.4 0.37 mA
  • ACL 1.28s sniff Slave 38.4 0.42 mA
  • SCO HV3 30ms sniff Master 38.4 19.8 mA
  • SCO HV3 30ms sniff Slave 38.4 19.0 mA
  • Standby Host connection - 38.4 40 µA

Function Diagram, Dimension

Schematic and reference design

LED Status

Mode LED Status Module Status
Master Even blinking, 150ms on/off searching mode
Master 5 times fast blinking, 2 seconds off pairing with recorded paired device
Master Keep on Connected
Slave Even blinking 800ms on, 800ms off wait for pairing
Slave Long-time on Connected
  • Slave mode LEDs
  • Status indicating LED: PIO(1), Use to indicating the status of the Bluetooth module, LED light flashes with the Bluetooth module state corresponding to the following table:
Mode Header text Header text
Slave Even Speed rapid flashing (200ms on/off) waiting for matching
Slave always on waiting for connection

Pin Definition

Pin Number Name Type Decription Programmed for BC04-B
1 UART-TX CMOS output UART data output Same
2 UART-RX CMOS input UART data input Same
3 UART-CTS CMOS input UART cancel send -
4 UART-RTS CMOS output UART request send -
5 PCM-CLK Double way PCM clock -
6 PCM-OUT CMOS output PCM data output -
7 PCM-IN CMOS input PCM data input -
8 PCM-SYNC double way Sync PCM data -
9 AIO(0) double way Programmable Analog I/O -
10 AIO(1) double way Programmable Analog I/O -
11 RESETB CMOS input Low TTL to reset -
12 3.3V Power Input Power 3.3V Same
13 GND Power Output GND Same
14 NC output Please NC it -
15 USB-DN double way USB data negative -
16 SPI-CSB CMOS input SPI chip selection -
17 SPI-MOSI CMOS input SPI data input -
18 SPI-MISO CMOS output SPI data output -
19 SPI-CLK CMOS input SPI clock -
20 USB-DP double way USB data positive -
23 PIO(0) double way Programmerable I/O (0) -
24 LED output Status indicating LED Status indicating LED
  • Pluse output means no connection
  • high TTL means connected
25 MCU-INT double way Programmerable I/O (2) MCU interrupts port
26 Clear double way Programmerable I/O (3) Memory clear key (short press)

Restore Defaults button (long press 3s)

27 SW/HW double way Programmerable I/O (4) Software / hardware main from settings port
  • set low (or vacant) hardware setup master-slave mode
  • set high 3.3V for the software to set master-slave mode
28 Master/Slave double way Programmerable I/O (5) Hardware master-slave mode settings port
  • set low (or vacant) mainly from the mode,
  • set high 3.3V mode
29 PIO(6) double way Programmerable I/O (6) -
30 PIO(7) double way Programmerable I/O (7) -
31 PIO(8) double way Programmerable I/O (8) -
32 PIO(9) double way Programmerable I/O (9) -
33 PIO(10) double way Programmerable I/O (10) -
34 PIO(11) double way Programmerable I/O (11) -

Use Guide

  • To Computer:
  1. Use TTL-RS232 convert board
  2. Module power supply 3.3 V
  3. TX and RX connected to RX and TX
  • To other modules
  1. TX and RX connected to RX and TX
  2. Module supply 3.3V
  • Module into the AT test methods
  1. Open HyperTerminal or other serial debugging tools to set the baud rate (default 9600), 8 data bits, 1 stop bit, no parity, no flow control
  2. Convert TTL level RS232 computer serial port connection
  3. Send commands AT carriage return line returns OK
  4. Module will only enter into AT commands mode before pairing, after pairing it's communication mode.

AT Commands

See the available Command list on this page. BC04-B Bluetooth serial module instruction is divided into Command (downlink command) and Indication (reporting instructions). (NOTE: AT commands are not case-sensitive, are carriage return, newline character at the end: \ r \ n AT instruction only in the state of the module is not connected to take effect once the Bluetooth module connected to the device, the Bluetooth module that entering data pass-through mode)
See the full Command List on this page.

Pairing Info

Pairing info.png

The pairing info of BC04B module, it will directly searching last paired module or says "pairable" when no devices can be paired
fff... This is the info I typed from cell phone

  • Bluetooth name: BC04-B
  • password: 1234
  • Baud rate: 9600

Switch Master/Slave Mode

Hardware settings:

Methods PIO (4) PIO (5) AT Commands Mode
Hardware LOW or NC HIGH - Master
Hardware LOW or NC LOW or NC - Salve
Software HIGH - AT ROLE1 Master
Software HIGH - AT ROLE0 Salve

Layout design points

  • BC04 Bluetooth module TTL level required to 3.3V, and for 5V TTL you will need 3.3-5V TTL conversion circuit.
  • Bluetooth signal by around a great impact, such as trees, metal, walls and other obstacles will Bluetooth signal absorption or shielding, so is not recommended being installed in a metal enclosure.
  • the metal will weaken the antenna, it is recommended that you should not paving and traces below the antenna in the layout design, preferably hollowed.

BC04 Breakout Board

Reference schematic