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STM32 single chip microcomputer controls the circuit of Bluetooth

The Bluetooth module is a PCBA board with integrated Bluetooth function. It is used for short-range wireless communication and is divided into Bluetooth data module and Bluetooth voice module according to functions. The Bluetooth module refers to the basic circuit circuit set of the integrated Bluetooth function, which is used for wireless network communication, and can be roughly divided into three types: a data transmission module remote control module. The general module has semi-finished properties and is processed on a chip basis to make subsequent applications easier.

Principle and structure of bluetooth

As a short-range wireless communication technology that replaces data cables, Bluetooth supports point-to-point and point-to-multipoint communication, wirelessly connecting various data and voice devices in a home or office into a piconet (Pico-net). The piconet can also be further interconnected to form a distributed network (scatter-net) to enable fast and convenient communication between these connected devices. This paper introduces the realization of the Bluetooth interface on the embedded digital signal processor OMAP5910. The DSP samples the analog signal and processes the digital signal after A/D conversion, and transmits it to the receiving end through the Bluetooth interface. Similarly, the DSP receives the Bluetooth. The digital signal that is obtained is D/A converted to become an analog signal.

The Bluetooth signal is transmitted and received using a Bluetooth module. This Bluetooth module is the company’s recently launched wireless signal transceiver chip that complies with the Bluetooth V1.1 standard. Its main features are: on-chip digital wireless processor DRP (DigitalRadioProcessor), digitally controlled oscillator, on-chip RF transceiver switch, built-in ARM7 embedded Processor, etc. When the signal is received, the transceiver switch is set to the receiving state, and the RF signal is received from the antenna and directly transmitted to the baseband signal processor via the Bluetooth transceiver. Baseband signal processing includes downconversion and sampling, using a zero-IF architecture. The digital signal is stored in RAM (capacity is 32KB) for ARM7 processor to call and process. ARM7 outputs the processed data from the encoding interface to other devices. The signal transmission process is the reverse process of signal reception. In addition, it also includes clock and Power management module and multiple general purpose I/O ports for different peripherals. Its host interface can provide a duplex universal serial port, which can easily communicate with the RS232 of the PC, or communicate with the buffered serial port of the DSP.

System hardware structure

The whole system consists of DSP, BRF6100, audio AD/DA, LCD, keyboard and Flash. DSP is the core control unit. Audio AD is used to convert the collected analog voice signal into digital voice signal. Audio DA converts digital voice signal into analog. Voice signal, output to headphones or speakers. Both the front end and the back end of the audio AD and DA have amplification and filtering circuits. In general, the audio AD and DA are integrated on one chip. The system uses TI’s TLV320AIC10 to set the sampling frequency to 8KHz, and the keyboard is used for input and control. The liquid crystal display displays various information. The Flash saves the program required by the DSP for the DSP to call up. The JTAG is the simulation interface of the DSP. The DSP also provides the HPI port. The interface can be connected with the computer, and the file in the computer can be downloaded and passed. DA playback can also transfer digital voice signals to a computer for storage and processing.

The DSP in the system uses OMAP5910, which is an embedded DSP introduced by TI. It has a dual processor structure and integrates ARM and DSP processors on-chip. ARM is used to control peripherals and DSP is used for data processing. The DSP in the OMAP5910 is a processor based on the TMS320C55X core. It provides two multiply-accumulate (MAC) units, one 40-bit arithmetic logic unit and one 16-bit arithmetic logic unit. Since the DSP uses a dual ALU structure, most of them Instructions can run in parallel, operate at up to 150MHz, and consume less power.

The ARM in the OMAP5910 is based on the ARM9 core TI925T processor, including a coprocessor, and the instruction length can be 16 or 32 bits. DSP and ARM work together to share memory and peripherals through MMU control. The OMAP5910 can be used in a variety of applications such as mobile communications, video and image processing, audio processing, graphics and image accelerators, and data processing. This system uses the OMAP5910 for personal mobile communications.

STM32 single chip microcomputer controls the circuit of Bluetooth

Many professional unprofessional friends want to try to make a mobile phone control light or a mobile phone to control the motor. The mobile phone reads the indoor temperature. Bluetooth is a good choice.

Below is the schematic of the STM32 main controller. This is the schematic I have drawn myself! I used STM32 to control Bluetooth and motor, relay, temperature and humidity sensor, read the photoresistor, and add the serial port. There are still a lot of STM32 resources that are not useful, if you have any needs, you can add them.

Next is the Bluetooth module, I chose the other modules of bc05 can also drop, read the data by myself. This is a good operation of the serial port Bluetooth, connected to the serial port of the microcontroller through the serial communication transparent transmission. You can set a simple agreement yourself.

bluetooth module
bluetooth module

The design of the power supply section is as follows. Here, it is powered by microUSB, which is the mobile phone charger. The power supply of Bluetooth is also controllable. I used a mos tube to make the switch, which is controlled by STM32.

power supply circuit
power supply circuit

The relay is controlled as follows, the switch of the relay is controlled by the single chip microcomputer, and the high level is turned on. The relay is turned on.

relay circuit
relay circuit

The temperature and humidity sensor, and the photoresistor are connected as follows.

humidity sesor circuit
humidity sesor circuit

The motor interface is as follows, there is no electric drive circuit, which can be bought. It can be done with a triode, and it can be done with ULN2003.

driver circuit
driver circuit

If you want to be able to communicate with the PC, add a serial port and download the program.

The next step is to write an embedded program. Bluetooth is easy to connect. It goes directly to transparent transmission and sets a protocol for itself. For example, x001 is to open the relay, x002 to open the motor and so on.

Android can download an open source Eclipse, then find Android Bluetooth basic program, change the interface, read the code, add a few buttons to get it, Xiaobian did not learn Android, but also modify the routine itself.

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