In the vast knowledge system of embedded hardware, there are many discrete knowledge points that can easily be overlooked. Therefore, this article aims to organize these easily forgotten or misunderstood concepts for reference and learning. The focus will be on the learning of push-pull, open-drain, high-Z state, and pull-up resistors. Basics of GPIO The following … Read more
Principles of Pull-Up Resistor Application1. When a TTL circuit drives a CMOS circuit, if the high level output from the TTL circuit is lower than the minimum high level of the CMOS circuit (generally 3.5V), a pull-up resistor is needed at the TTL output to increase the high level output value. ……………………….2. An OC gate … Read more
The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, it is common to encounter questions about whether pull-up and pull-down resistors are needed and what resistance values are appropriate. Below, we will analyze these issues in detail. 1. Why are Pull-Up and Pull-Down Resistors Needed? 1) When the … Read more
The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, one often encounters the question of whether to add pull-up and pull-down resistors and what resistance values are appropriate. Below, we will analyze these issues in detail. 1. Why are Pull-Up and Pull-Down Resistors Needed? 1) When the differential … Read more
The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, one often encounters the question of whether to add pull-up and pull-down resistors and what resistance values are appropriate. Below, we will conduct a detailed analysis of these issues. 1. Why are Pull-Up and Pull-Down Resistors Needed? According to … Read more
Unveiling I2C Pull-Up Resistor Value Techniques: 5 Key Design Points and Practical Cases Introduction: Why Must I2C Be Equipped with Pull-Up Resistors? In the communication between the main control chip and other modules (such as cameras, sensors, etc.) in embedded systems, the I2C bus is widely used due to its simplicity, reliability, and low cost. … Read more
I2C Bus (Inter-Integrated Circuit）is a two-wire serial bus developed by PHILIPS for connecting microcontrollers and their peripherals. It is a widely adopted bus standard in the field of microelectronics control. It is a special form of synchronous communication, characterized by fewer interfaces, simple control methods, fewer device packaging forms, and high communication rates. The I2C … Read more
I2C is a two-wire serial communication bus, consisting of an SCL signal and an SDA signal. SCL is the clock signal sent from the master device, while SDA is the data signal, which is bidirectional, allowing devices to send and receive data through the SDA signal. When designing the I2C signal circuit, we add a … Read more
I2C is a common serial communication interface, which is available on most processors. The I2C interface is an open-drain structure, so pull-up resistors are needed in the design to drive the high level. As shown below: Rp is the pull-up resistor, and the dashed box contains the internal I2C controller structure of the chip (for … Read more
Follow+Star Public Number, don’t miss wonderful content Source | Zhou Ligong The RS-485 bus is widely used in communication, industrial automation, and other fields. In practical applications, it is often encountered whether to add pull-up and pull-down resistors and what size of resistors is appropriate. Below we will analyze these issues in detail. Why are … Read more