Please check if this program is correct. It doesn't work when I download it.

dinghao1

Please check if this program is correct. It doesn't work when I download it. [Copy link]

 

dinghao1

dinghao1

AT89S52 microcontroller used

leo121

Try calling delay_us instead of delay_ms to see if it works. Is it optimized away during compilation?

dinghao1

leo121 posted on 2017-12-18 17:55 Try calling delay_us instead of delay_ms to see if it works? Is it optimized away during compilation?

I changed it, but it doesn't work. The delay program should be fine. I've used it with STM32 before.

qwqwqw2088

Is P2^6 connected to the hardware REEP correct? Just call a delay directly for 51 delay, and there is no need to nest anything or change R23 to a larger resistance value. There is no problem with the circuit. The program for 51 microcontroller to drive the buzzer can be found on the Internet. Try it and select the right driver port.

jj1989

First confirm whether the buzzer is active or passive.

xu__changhua

There are unreasonable places in both software program and hardware circuit. The software delay time is too long, try changing 500 to 5. You can't compare with the delay of STM32, the clock of STM32 is 72M, and the clock of AT89S52 is only equivalent to 1M. The transistor selection in the circuit is wrong, use 8550-PNP transistor instead, reverse the emitter and collector, short-circuit R23, and open R24.

dinghao1

qwqwqw2088 posted on 2017-12-18 20:25 Is P2^6 connected to the hardware REEP correct? The delay of 51 can just call a delay directly, and there is no need to nest anything or change R23 to a larger resistance value. The circuit...

dinghao1

qwqwqw2088 posted on 2017-12-18 20:25 Is P2^6 connected to the hardware REEP correct? 51's delay can just call a delay, and there is no need to nest anything or change R23 to a larger resistance value. The circuit...

The key is that after I removed R23, I used a multimeter to measure the microcontroller pin directly, and it was always 5v, without any change

dinghao1

jj1989 posted on 2017-12-18 20:44 First confirm whether the buzzer is active or passive.

Active

dinghao1

xu__changhua posted on 2017-12-18 21:35 There are unreasonable places in both the software program and the hardware circuit. The software delay time is too long, try changing 500 to 5. You can't compare with the delay of STM32...

After changing the program, I removed R23 and directly used a multimeter to measure the microcontroller pin. It has always been 5v, no change. This is not because the 51 load is not enough.

曹伟1993

The main function is not right. It will eventually stop in WHILE() and will not move. Maybe the delay in front of you is too short, and you can't hear the sound at all, so you may see the phenomenon you said.

dinghao1

Cao Wei 1993 posted on 2017-12-19 11:13 The main function is not right, it will always stop in WHILE() and will not move. Maybe the delay in front of you is too short, and you can't hear the sound at all, so...

I changed the delay time, but there is no response

ienglgge

dinghao1 posted on 2017-12-19 08:18

Take a look at the delay of this multi-layer for loop and see what the actual delay is. An oscilloscope is best. If you don't have one, use a multimeter. Adjust the delay to the multimeter and you can see the change. It can be several hundred ms, or even longer. Measure the change in the io port level. See how the transistor base voltage changes.

chenbingjy

Try putting those four statements in a while loop.

曹伟1993

dinghao1 posted on 2017-12-19 13:45 I changed the delay time, but there is no response

It is not a time problem, put the buzzer part in the main function into the WHILE and see if it works. I don't see any problems in other places.

dinghao1

ienglgge posted on 2017-12-19 14:18 Take a look at the delay of this multi-layer for loop and see what the actual delay is. An oscilloscope is best. If you don't have one, use a multimeter. Adjust the delay to the multimeter and you can...

No response after downloading the program, voltage remains unchanged

dinghao1

dinghao1

Is this the program that has been downloaded?