Analysis of the reasons why the reset circuit does not work during the MCU Proteaus simulation

Tacking

Analysis of the reasons why the reset circuit does not work during the MCU Proteaus simulation [Copy link]

When I was simulating a microcontroller with Proteaus, the reset circuit in the minimum working system did not work. The circuit diagram is shown below:

It is found here that the voltage is incorrect and RST cannot perform the reset operation.

When I changed the resistor from 10K to 100Ω, the reset circuit worked properly and the voltage was normal, as shown below:

Please let me know why it is normal to change to 100Ω. Is it because in Proteaus simulation, the time is calculated according to the 12MHz of the crystal oscillator, so the charging and discharging time of 10K resistor is 0.1s, which is very short in real life, but in actual Proteaus simulation, this time is very long, and the capacitor is always in the charging state.

wangerxian

Proteus had this problem a long time ago.

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In actual hardware, a 10KΩ resistor can provide an appropriate reset time, and the simulation model of the Proteus software has an error with the actual hardware.

qwqwqw2088

The simulation software also follows the RC time constant. When it changes from 10KΩ to 100Ω, the time constant decreases, the charging speed becomes faster, and the RST pin of the microcontroller reaches the threshold voltage. It only meets the microcontroller reset requirements in the Proteus software.

Generally, after the hardware circuit is simulated by software, the actual circuit still needs to fine-tune the hardware parameters.

Tacking

Thank you very much for your help, I finally understand!