The dotted box shown in Figure 1 is an interface circuit. By analyzing the truth table, its sending and receiving processes are as follows:
when DI=0 at the sending end, DE/RE=1 sends a 0 level, and RO=0 at the receiving end; when DI=1 at the sending end, DE/RE=0, VA=VB=2.5V, and RO=1 at the receiving end due to the pull-up resistor.
Reference address：RS-485 interface circuit and test circuit with automatic transceiver conversion
when DI=0 at the sending end, DE/RE=1 sends a 0 level, and RO=0 at the receiving end; when DI=1 at the sending end, DE/RE=0, VA=VB=2.5V, and RO=1 at the receiving end due to the pull-up resistor.
A 1kHz TTL square wave is added to the TXo end of this interface circuit to test the circuit. When the 120Ω terminal resistor is not added, the voltage change process of the 485-A and 485-B pins of the interface chip is about 50μs, as shown in Figure 2. The rising edge of the Ro waveform at the receiving end has a significant delay of about 30 to 40μs (compared with the data transmitting end DI), causing a large transmission error; when the 120Ω terminal resistor is added, the delay is significantly reduced to about 3μs.
When this circuit sends a high level, the transmitter is in a high impedance state, all interfaces on the bus are in a receiving state, the bus is idle, and other interfaces are allowed to send data, so it is easy to introduce bus conflicts. Especially when sending quotient level bits continuously, the longer the transmitter is in a high impedance state, the greater the probability of introducing bus conflicts.
Previous article：Design of CAN Bus Interface Based on DSP
Next article：Discussion on the development of digital camera technology based on DSP
Recommended ReadingLatest update time:2024-11-16 16:40
How to choose RS-232/RS-485/RS-422 converter
Your computer or device may only have an RS-232 port. If you want to conduct effective and reliable RS-485 or RS-422 communication, you need to choose the right RS-232/RS-485/RS-422 converter for your application. Is it half-duplex RS-485 or full-duplex RS-422? Is it optoelectronic isolation or non-optical isolation?
[Microcontroller]
ST GSM RF IC DataSheet
RF and Wireless Technology Acronyms for Beginners
Design of RS-485 Optoelectronic Transceiver Module with Baud Rate Adaptation
Recommended Content
Latest Embedded Articles
- Huawei's Strategic Department Director Gai Gang: The cumulative installed base of open source Euler operating system exceeds 10 million setsOn November 15, the first AI native open source operating system openEuler, openEuler 24 03 LTS version, was officially released on June 6 this year. ...
- Analysis of the application of several common contact parts in high-voltage connectors of new energy vehiclesIntroduction: Connectors are used in every car. The device uses electrical, optical and other signals to control the corresponding mechanical force to connect, disconnect and convert, thereby realizing the corresponding circuit or optical channel conversion. ...
- Wiring harness durability test and contact voltage drop test methodBased on the QC T 29106-2014 standard, this paper proposes a new durability characteristic test and contact voltage drop test method, and conducts experimental verification on these two test methods. ...
- Sn-doped CuO nanostructure-based ethanol gas sensor for real-time drunk driving detection in vehiclesMetal oxides and their composites with other materials (such as MXenes and metal chalcogenides) can be used to achieve different ...
- Design considerations for automotive battery wiring harnessThe battery is one of the power sources of the car. When the generator stops working and the engine is started, all the power is output from the battery. When the engine is idling or working at a low speed, the power generation of the generator cannot meet the demand. ...
- Do you know all the various motors commonly used in automotive electronics?
- What are the functions of the Internet of Vehicles? What are the uses and benefits of the Internet of Vehicles?
- Power Inverter - A critical safety system for electric vehicles
- Analysis of the information security mechanism of AUTOSAR, the automotive embedded software framework
He Limin Column
Microcontroller and Embedded Systems Bible
Professor at Beihang University, dedicated to promoting microcontrollers and embedded systems for over 20 years.
MoreSelected Circuit Diagrams
MorePopular Articles
- Innolux's intelligent steer-by-wire solution makes cars smarter and safer
- 8051 MCU - Parity Check
- How to efficiently balance the sensitivity of tactile sensing interfaces
- What should I do if the servo motor shakes? What causes the servo motor to shake quickly?
- 【Brushless Motor】Analysis of three-phase BLDC motor and sharing of two popular development boards
- Midea Industrial Technology's subsidiaries Clou Electronics and Hekang New Energy jointly appeared at the Munich Battery Energy Storage Exhibition and Solar Energy Exhibition
- Guoxin Sichen | Application of ferroelectric memory PB85RS2MC in power battery management, with a capacity of 2M
- Analysis of common faults of frequency converter
- In a head-on competition with Qualcomm, what kind of cockpit products has Intel come up with?
- Dalian Rongke's all-vanadium liquid flow battery energy storage equipment industrialization project has entered the sprint stage before production
MoreDaily News
- Allegro MicroSystems Introduces Advanced Magnetic and Inductive Position Sensing Solutions at Electronica 2024
- Car key in the left hand, liveness detection radar in the right hand, UWB is imperative for cars!
- After a decade of rapid development, domestic CIS has entered the market
- Aegis Dagger Battery + Thor EM-i Super Hybrid, Geely New Energy has thrown out two "king bombs"
- A brief discussion on functional safety - fault, error, and failure
- In the smart car 2.0 cycle, these core industry chains are facing major opportunities!
- The United States and Japan are developing new batteries. CATL faces challenges? How should China's new energy battery industry respond?
- Murata launches high-precision 6-axis inertial sensor for automobiles
- Ford patents pre-charge alarm to help save costs and respond to emergencies
- New real-time microcontroller system from Texas Instruments enables smarter processing in automotive and industrial applications
Guess you like
- MSP430: Input Capture
- High Voltage Impedance Tuning Quick Guide
- K210 face recognition environment construction process
- Charge up! The latest generation of ACF UCC28782 ultra-small fast charging adapter!
- Proteus simulation experiment of single chip microcomputer communication
- 【TI recommended course】#Power system design tools#
- Question about username
- NeoPixel simulates fluid physics motion
- BMP library management based on FPGA.pdf
- Making some preparations for the flag I set up on the forum this year (first time shopping at the ghost market)
京公网安备 11010802033920号