1, the i2c bus is a two-wire serial bus; The basic signal lines of SPI bus are three transmission lines, namely SI, SO, SCK; The can bus is a field bus, which is mostly used for communication on vehicles or industrial equipment. Not only is the protocol different, the communication distance, the physical connection is also different.
2, I2C fewer lines, I think than UART, SPI more powerful, but technically more trouble, because I2C needs to have two-way IO support, and the use of pull-up resistance, I think the anti-interference ability is weak, generally used for the same board card coreCommunication between chips, less used for long-distance communication.
3, I2C: (Inter-Integrated Circuit) bus is used to connect the microcontroller and its peripherals. The I2C bus supports any IC production process (NMOS CMOS, bipolar). Two wires, the Serial data (SDA) and Serial clock (SCL) lines, pass information between devices connected to the bus.
4, the main advantage of the I2C bus is its simplicity and effectiveness. Since the interface is directly on top of the component, the I2C bus occupies empty spaceThe room is very small, reducing the space of the circuit board and the number of chip pins, reducing the cost of interconnection.
5, i0; i--) {... ; if (...) break; ... When the level of SDA is low, it jumps out of the loop, indicating that the slave has ACK at this time, which can indicate that the I2C device is pulled down; If it is high, it has been judged the complete cycle, and when it is still high at the end, it indicates that there is no
6, the biggest difference: CAN-bus, serial communication is used for communication between devices, IIC, SPI is used for communication between components.What is the relationship between N bus? CAN is a chip
stm32 is a single chip microcomputer, that is, a control chip. CAN bus is a communication protocol, just like our serial port, is used for communication between devices. Just like our serial port needs a MAX232 chip for logical conversion, CAN also needs a dedicated CAN chip support.
CAN bus communication system is a serial communication, better than RS485 bus, is currently a more commonly used industrial bus. For example, the electrical part of the car uses the CAN bus to achieve communication. withIt is very troublesome to compose CAN communication with ordinary single chip microcomputer, and it needs to configure CAN interface circuit.
The CAN transceiver and controller are the center of data transmission, they process CAN messages respectively, and the functional circuit performs signal acquisition or control tasks.
Multiple communication nodes CAN be mounted on the CAN bus, and the signals between nodes are transmitted through the bus to realize the communication between nodes.
STM32F407 platform uses TJA1040 CAN transceiver, this chip is designed for closed-loop network, with real-time, multi-host communication, differential signal transmission, non-Destructive arbitration, broadcast, and other features.
1. The CAN bus is connected to the physical bus through the two output terminals CANH and CANL on the CAN controller interface chip, and the state of the CANH terminal can only be high level or suspended state, CThe ANL terminal can only be in a low or suspended state.
2, if the pen is no problem, it should be pin-to-ground or the capacitance between the pins is too large.
3, CAN bus driver) F040 built-in CAN bus protocol controller, as long as the external bus driver chip and appropriate anti-interference circuit CAN easily establish a CAN bus intelligent measurement and control node. TJA1050T CAN bus driver of PHILIP company is used in this design. The hardware principle diagram of CAN bus communication is shown in Figure 3.
4, CAN transceiver coreThe heart lies in its two key pins, CANH and CANL, which correspond to the high and low level signals of the bus, respectively. The CAN system uses symmetric transmission to ensure electromagnetic compatibility, and the transmission medium is constructed through two unshielded twisted pair wires to ensure the stable transmission of the signal.
The STM32 interconnect series is available in two models: STM32F105 and STM32F107. The STM32F105 has USB OTG and CAN0B interfaces. SThe TM32F107 adds an Ethernet 10/100 MAC module to the USB OTG and CAN0B interfaces.
DevKit1207 is a development board and evaluation kit based on ARM 32-bit Cortex-M3 STM32F207 processor launched by Shenzhen Tianmo Technology Co., LTD. The DevKit1207 evaluation kit provides all peripheral routines for users to quickly evaluate all peripherals.
The stm321032ze belongs to the STM32 series which is STMThe 32 Series ARM is designed for embedded applications requiring high performance, low cost, and low power consumption.
SPI, SDIO, FMSC, UART, I2C some also have camera interface, digital audio interface. Mainstream products (STM32F0, STM32FSTM32F3), ultra-low power consumption (STM32L0, STM32LSTM32LSTM32L4) (STM32FSTM32FSTM32FSTM32H7), high performance products.
The STM32 connected series enhances the audioPerformance, using an advanced phase-locked loop mechanism to achieve audio level I2S communication. Combined with USB host or slave functions, the STM32 can read, decode and output audio signals from external memory (USB stick or MP3 player).
Transceiver. According to the relevant information, the vp1050 chip has a pin function, and its function includes the interface between the controller area network (CAN) protocol controller and the physical bus, which is a standard high-speed CANThe transceiver.
VP1050 SOIC-8 package, a chip that can be used for interfaces. For example, it can be used for usb interface. CAN be used for CAN interface.
Two single-channel alternatives are recommended. The specific explanation is as follows: VP1050 SOIC-8 package, a chip that can be used for interfaces. For example, it CAN be used for usb interface or CAN interface. This is an optovoltage output optocoupler. Toshiba has a product of this kind. However, there are few dual-channel outputs now, and it is recommended to use two single-channel alternatives.
sn8p2501bpb single chip computerMust burn the original single-chip computer program code to run. The pin function is to input the positive power terminal of the Vcc chip in the sn8p2501bpb single chip, the typical value is adjusted to 5V, and then the low input of the GND chip, that is, the negative power terminal, can be used normally.
First, the pins of the chip are used for data transmission. In digital chips, pins are usually used to receive and send data to achieve communication with other devices. By correctly connecting and configuring the pins of the chip, we can implement the input and output of data, so that the chip can receive messages from external devicesAnd make corresponding treatment.