GPIO_Mode_Out_PP Push-Pull Output Normal Digital Output GPIO_Mode_Out_OD Open-Drain Output Level Conversion, Bus GPIO_Mode_AF_PP Alternate Function Push-Pull SPI, USART, etc. GPIO_Mode_AF_OD Alternate Function Open-Drain I2C, Multi-Master Bus Alternate Functionality · The pin is no longer used as a regular GPIO · Instead, it is connected to specific peripherals inside the chip (such as USART, SPI, I2C, … Read more
Hello everyone, I am Remember Cheng.I previously wrote an article:Why I2C Requires Pull-Up ResistorsI2C requires pull-up resistors due to its open-drain structure, which cannot output a high level, so external pull-up resistors must be added.When using SPI, we find that pull-up resistors are not needed. This is mainly because SPI typically uses a push-pull structure, … Read more
Bidirectional IO Port Output: Complementary Push-Pull In the 51 microcontroller, the P0 port operates in standard IO mode as a quasi-bidirectional IO port. When in the second functional state, it becomes a standard bidirectional IO port. Due to the output requirements of bidirectional IO ports needing to output high and low levels, complementary push-pull circuits … Read more
1. First, let’s discuss open-drain output and push-pull output First, watch the video explanation: The following video is from Guo Tianxiang Push-Pull Output Structure and Principle: A push-pull output circuit consists of two complementary transistors (usually an NPN transistor and a PNP transistor). In this structure, when the input is high, the upper transistor (like … Read more
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
The application of push-pull circuits is very extensive, such as the push-pull mode output of microcontrollers, PWM controllers output, bridge driver circuits, etc. The English term for push-pull is: Push-Pull, which literally means push-pull. Therefore, push-pull circuits are also called push-pull type circuits. The essence of push-pull circuits is power amplification, which enhances the driving … Read more