The number of DNJZ cycles of the MCU

The loop is either executed first and judged later, or judged first and then executed.

Either way, it is performed 3 times.

r6=03h djnz r6, execute first and then judge: execute, judge 3-1=2 is not zero; execute, judging that 2-1=1 is not zero; executed, and the cycle 1-1=0 is judged to be zero. So it was done 3 times.

Subtract once at the end of each loop, and count how many times you subtract yourself? The first cycle ends when 3-1=2, the second cycle ends when 2-1=1, and the third cycle ends when 1-1=0.

Let's assume r6 = 03h

djnz r6, $3-1=2 once, 2-1=1 twice, 1-1=0 three times, after three executions = 0 , down to the next level.

Pay attention to the format of DJNZ.

loop.

djnz r6,loop

The first time it was executed to DJNZ, the loop ** had already been executed once, so with the next two times you said, it was three times.

mov r6,#03h

mov r7,#00h

loop:inc r7

djnz r6,loop

You see, the above paragraph **, after execution, r7=?, I understand it, and I know why I said it 3 times.

It's an endless loop, r0 can never be reduced to 0. Every time you subtract 1 and don't get zero, you jump to the loop and continue to execute, and then r0 is 3 again, so you can never jump out!

It's an endless loop.

The correct way to write it is:

mov r0,#

loop:…djnz r0,loop

Cycle three times.

mov r0,#38;or MOV R0, 26H; All right, but note that the previous sentence is a decimal number without an h. The cycle * times you said only refers to the decimal system, so it is more convenient to copy it directly in the decimal system if you define the number of times. In other bases, use the number of decimal cycles you want.

JZ: Jump Zero.

jnz: jump not zero transfer cjne: compare jump not equal

djnz: decrease jump not zero minus 1 does not transfer to zero.

The single-chip microcomputer communicates with the single-chip microcomputer, and the direct serial port docking can be done (txd1 - rxd2, rxd1 - txd2).

Multi-machine communication set up a host, (txd1 - rxd2 - rxd3 --rxdn , rxd1 - txd2 - txd3 --txdn )

The way is similar to PC and MCU. Note that the baud rate should be the same.