What are data, address, and instruction in a single chip microcomputer system?

Data, address, instruction: The reason why these three are put together is that the essence of these three is the same - numbers, or a sequence of '0' and '1'. In other words, addresses and instructions are also data. Instruction: A number specified by the designer of the microcontroller chip. It has a strict one-to-one correspondence with the commonly used instruction mnemonics and cannot be changed by the developer of the microcontroller. Address: It is the basis for finding the internal and external storage units and input and output ports of the microcontroller. The address value of the internal unit has been specified by the chip designer and cannot be changed. The external unit can be determined by the microcontroller developer, but some address units must be there (see the execution process of the program for details). Data: This is the object processed by the microprocessor. It is different in various application circuits. Generally speaking, the data being processed may have the following situations:

1. Address (such as MOV DPTR, #1000H), that is, address 1000H is sent to DPTR.

2. Mode word or control word (such as MOV TMOD, #3), 3 is the control word.

3. Constants (such as MOV TH0, #10H) 10H is the timing constant.

4. Actual output value (such as P1 port connected to colored lights, to make all lights bright, execute the instruction: MOV P1, #0FFH, to make all lights dark, execute the instruction: MOV P1, #00H) Here 0FFH and 00H are both actual output values. Another example is the font code used for LED, which is also the actual output value. If 

you understand the nature of addresses and instructions, it is not difficult to understand why the program will run away during operation and the data will be executed as instructions.