1. core module use HC-05 sub-host module, interfaces include VCC, GND, TXD, RXD, KEY, bluetooth state pin (STATE), output low if not connected, high if connected
2. LED indicates the connection status of bluetooth, quick flash means no connectivity, slow flash means entering AT mode, double flash means bluetooth is connected
3. bottom board is equiped with anti-reversion diode, with 3.3V LDO, input voltage 3.6 ~ 6V, unpaired current about 30mA, paired about 10mA, input voltage no more than 7V!
4. interface level 3.3V, can be connected directly to various MCU (51, AVR, PIC, ARM, MSP430, etc.), and 5V MCU, no need for MAX232 and cannot connect with MAX232.
5. for open space, effective distance is 10 meters (power level CLASS 2), more than 10 meters is possible, but no guarantee on connection quality at this distance
6. after pairing, used as full duplex serial port, no requirement in knowing any any bluetooth protocol, support 8 data bits, 1 stop bit, can set odd-even check communication format, which is the most commonly used communication format, does not support other formats.
7. can enter AT command mode, set parameters, and query information by pull up 34 pins
8. small size (3.57 cm * 1.52 cm), production SMT factory, ensure SMT quality. It is protected by transparent heat shrinkable tube, dustproof and nice, and with certain antistatic effect.
9. can switch for host or sub-host mode and connect specified device by AT command
10. support standard baud rate between 4800bps~1382400bps