"MCS51单片机键盘接口技术：去抖动、按键编码和独立式按键设计方法详解"

MCS51 single-chip microcontroller interface technology is a crucial aspect of embedded system design. In the presentation "Chapter 09 MCS51 Single-Chip Microcontroller Interface Technology," which was delivered on May 29, 2020, various key concepts related to keyboard interfacing were discussed. The presentation began by addressing the issue of switch bounce in keyboard interfaces, which can lead to multiple erroneous readings by the CPU due to rapid fluctuations in the signal caused by mechanical contacts within the keys. Two main methods of debouncing were highlighted – hardware debouncing using an RC filter circuit and software debouncing through the execution of a delay subroutine after detecting a key press. Furthermore, the encoding of keystrokes was explained, detailing how binary combinations of input/output lines are used to represent key codes and how sequential codes are arranged by determining row and column numbers. This encoding method facilitates easy identification and processing of key inputs by the microcontroller. The presentation also discussed independent key interfaces, which are characterized by individual keys being isolated and having their own circuit configurations. While this setup offers flexibility and simplicity in software structure, it may require a significant number of I/O lines, making it more suitable for scenarios with a limited number of keys. Overall, the "Chapter 09 MCS51 Single-Chip Microcontroller Interface Technology" presentation provided valuable insights into the technical aspects of keyboard interfacing in embedded systems. It highlighted the importance of debouncing techniques, effective encoding methods, and considerations when designing independent key interfaces. These concepts are essential for ensuring reliable and efficient communication between the microcontroller and external input devices.