SPECIFICATIONS

TXD: The sender, usually referred to as its own sender, must be connected to another device's RXD for normal communication.

RXD: The receiving end, usually represented as its own receiving end, must be connected to another device's TXD for normal communication.

During normal communication, the TXD itself is always connected to the RXD of the device!

Self receiving and spontaneous: During normal communication, the RXD is connected to the TXD of other devices. Therefore, if you want to receive data sent by yourself, as the name suggests, it means that your own TXD is directly connected to the RXD to test whether its transmission and reception are normal. This is a fast and simple testing method. When a problem occurs, the first step is to perform this test to determine whether the product is faulty. Also known as loop testing.

1.2 Level Logic:

TTL level: Usually, data representation is in binary format, with+5V equivalent to logic "1" and 0V equivalent to logic "0". This is called TTL signal system and is a positive logic system

RS232 level: using -12V to -3V, equivalent to logic "0",+3V to+12V logic level, equivalent to logic "1", is negative logic

1.3 Product Features:

1. The core module uses HC-05 as a slave module, with output interfaces including VCC, GND, TXD, RXD, KEY pin, and Bluetooth connection status output pin (STATE). The output is low when not connected and high when connected

2. LED indicates Bluetooth connection status, flash indicates no Bluetooth connection, slow flash indicates entering AT mode, double flash indicates Bluetooth is connected and the port is open

3. The base plate is equipped with anti reverse diodes, with a 3.3V LDO and an input voltage of 3.6-6V. The current is about 30mA when not paired and about 10mA when paired. The input voltage must not exceed 7V!

4. The interface level is 3.3V, which can be directly connected to various microcontrollers (51, AVR, PIC, ARM, MSP430, etc.), and 5V microcontrollers can also be directly connected without MAX232 and cannot pass through MAX232!

5. The effective distance of open space is 10 meters (power level is CLASS 2), and it is also possible to exceed 10 meters, but the connection quality at this distance is not guaranteed

6. After pairing, when using a full duplex serial port, there is no need to understand any Bluetooth protocol. It supports 8-bit data bits, 1-bit stop bits, and parity check communication formats, which are also commonly used communication formats and do not support other formats.

7. You can enter AT command mode by raising pin 34 to set parameters and query information

8. Compact size (3.57cm * 1.52cm), factory patch production ensures patch quality. Equipped with transparent heat shrink tubing, it is dust-proof and aesthetically pleasing, and has a certain anti-static ability.

9. Can switch to master or slave mode through AT command, and can connect to specified devices through AT command

10. Supports standard baud rates ranging from 4800bps to 1382400bps

1.4 Product Usage:

After pairing, it only needs to be used as a fixed baud rate serial port, so any serial port device with the communication format of "fixed baud rate, 8-bit data bits, no parity check" can directly replace the original wired serial port without modifying the program. Such as data collection, intelligent vehicles, serial printers, outdoor dot matrix strip screen control, etc.

Paired with a computer: Suitable for communication between a computer and a device via Bluetooth serial port, the usage method is the same as that of a serial port

Paired with mobile phone: suitable for communication between mobile phone and device through Bluetooth serial port, using the same method as serial port

Paired with Bluetooth host: Suitable for two devices to communicate directly through Bluetooth serial port, such as between microcontrollers, wired serial ports between microcontrollers, etc. The usage method is the same as the serial port

Flexible use:

Baud rate conversion, as the receiving and transmitting ends can choose their own baud rates, can be used as a device for baud rate conversion when the data volume is small.