Bluetooth protocal : Bluetooth Specification v2.0+EDR
Frequency : 2.4GHz ISM band
Modulation : GFSK(Gaussian Frequency Shift Keying)
Emission power : <=4dBm, Class 2
Sensitivity : <=-84dBm at 0.1% BER

Speed : Asynchronous: 2.1Mbps(Max) / 160 kbps, Synchronous: 1Mbps/1Mbps

Security : Authentication and encryption
Profiles : Bluetooth serial port

CSR chip : Bluetooth v2.0
Wave band : 2.4GHz-2.8GHz, ISM Band
Protocol : Bluetooth V2.0
Power Class : (+6dbm)
Reception sensitivity: -85dBm
Voltage : 3.3 (2.7V-4.2V)
Current : Paring – 35mA, Connected – 8mA
Temperature : -40~ +105 Degrees Celsius
User defined Baud rate : 4800, 9600, 19200, 38400, 57600, 115200, 230400,460800,921600 ,1382400.
Dimension : 26.9mm*13mm*2.2mm

• Default serial port setting : 9600, N, 8, 1
• Pairing code : 1234
• Running in slave or master role

Pinout

• Key       : ??
• Vcc       : 3.6v to 6v
• GND
• TXD       : link to opposite side RX (TTL 3v3 on this revision)
• RXD       : link to opposite TX (TTL 3v3 on this revision)
• STATE   : HIGH : command mode, LOW : operation mode.Active command mode with a 10K pull-up resistor.
•  Onboard red led (PIO9) : Used to control LED indicating paring. It will be steady on when paring is successful.

Note that I/O is 3v3 TTL level, and does not accept 5v. To convert to/from, for instance, an Arduino, you can use a voltage divider or with two resistor where one is a pull-down, like in open brain wave interface hardware for RX and a FET for TX. This is true for this actual revision, 1.05. Version 1.2 accepts 5v level signals. You can also use a level shifter, likethis one. Note that newer MCU uses directly 3.3v, and thus the JY-MCU is useable directly (Stellaris Launchpad, STM32 Discovery..).

Command mode

Default serial port setting in command mode : 9600, N, 8, 1

Use a serial adapter like uartsbee, and connect the JY-MCU using local serial port (the bluetooth port will not answer to AT commands).

Use NOTHING end line : no CR nor LF.

Test using plain « AT » command : the board must answer « OK » if ready to answer AT commands.

Activation

Poweroff, put a 10k pull-up resistor on the « state » pin (PIO11), power on.

Command list

to come back to normal mode, power down, remove pull-up, and power up.

 Note : with build-in reset circuit, reset is completed automatically after powered on.