Ask about the MCU

In this case, it depends on sp, ret is equal to (sp) pch, sp-1 sp (sp) pcl, sp-1 sp

It is to look at the stack, when using lcall or acall, the microcontroller first puts the PC value into the stack, and then jumps to the subroutine, and RET is to send the value in the stack back to the PC. If there is no lcall or acall followed by ret, the program will run away, and what value is in the sp, it will jump to the address of what value, usually it will crash, or it may go back to the beginning and run again.

Usually the next sentence after the invocation statement....

Haven't thought about it yet! I'm going to try it tomorrow.

This extended address can only be accessed with a fixed address line, and P2 can only be operated separately by using port P2, instead of directly accessing the address.

The affected is bit8 in the 16-bit address, the affected is bit9 in the 16-bit address, and the address range is fdf8h fdffh(1111 1101 1111 1000 1111 1101 1111 1111) ......And so on.

Summary. The single-chip microcomputer uses the Harvard structure. Q&A:

First, the address space of 64KB program memory and 64KB off-chip data memory is 0000h-0ffffh, and the address space is overlapping, how can they be distinguished? MCS-51 microcontroller reads and writes to off-chip data memory and program memory through different signals, the read and write of off-chip data memory are controlled by RD and WR signals, and the read of program memory is controlled by PSEN signals and realized by using different program instructions.

The single-chip microcomputer uses the Harvard structure. Q&A: First, the address space of 64KB program memory and 64KB off-chip data memory is 0000h-0ffffh, and the address space is overlapping, how can they be distinguished?

MCS-51 microcontroller reads and writes to off-chip data memory and program memory through different signals, the read and write of off-chip data memory are controlled by RD and WR signals, and the read of program memory is controlled by PSEN signals and realized by using different program instructions.

The problem of single-chip microcomputer, please help to do it.

First, the address space of 64KB program memory and 64KB off-chip data memory is 0000h-0ffffh, and the address space is overlapping, how can they be distinguished? MCS-51 microcontroller reads and writes to off-chip data memory and program memory through different signals, the read and write of off-chip data memory are controlled by RD and WR signals, and the read of program memory is controlled by PSEN signals and realized by using different program instructions.