Compilation Notes on Data Communication

1. Number Representation

In microcomputers, operations are divided into two categories: one is arithmetic operations: including addition, subtraction, multiplication, and division. There are also logical operations: AND, OR, NOT, XOR. In fact, computers only understand addition operations, and all other operations are based on it. Multiplication is similar to the operation of accumulation and doubling. Similarly, division is similar to accumulation and subtraction. For more advanced operations, the essence is still the increase and decrease of quantity. This involves philosophy. Newton elaborated on the guiding significance of this point in detail in the book "Mathematical Principles of Natural Philosophy". As for himself, he also carried out his research on natural science under several philosophical principles.
Qunfang, the original code, inverse code, and complement code you mentioned are actually some concepts for introducing subtraction into microcomputer operations. You can try to discuss some issues with Hu Yefeng, who has his own research on "Mathematical Principles of Natural Philosophy".
To do operations, you must have numbers, so how are numbers represented in computers?

2. Data Communication

In a microcomputer, there are two types of interfaces: parallel interface and serial interface, depending on the different data transmission methods between the microcomputer and the peripherals. The characteristics of the parallel interface are: using multiple transmission lines to transmit each bit of data at the same time, usually eight or sixteen bits of data each time. Similarly, in parallel communication, if you want to transmit several bits of data, you have to set up several data lines. The interface that implements parallel communication is called a parallel communication interface. In addition to parallel data lines, at least two handshake (communication) signal lines must be set between the parallel interface and the peripherals.

The characteristics of the parallel interface are: 1. Multiple data lines and fast transmission speed. 2. Suitable for short-distance data transmission occasions. 3. The transmitted information does not require a fixed format. In serial communication, it is required