The reset circuit of the stm32f411 chip in the Wang Gong's small board is as follows:
In fact, this circuit is wrong, after the actual measurement, stm32f411 chip runtime reset pin is high, and in this circuit diagram, in fact, the stm32f411 chip runtime reset pin level to see the low level, according to this circuit, press the button, Will cause the level to jump to the high level to trigger the reset, however, in fact it is not so, stm32f411 reset pin in the pull-up resistor (measured), so even if the key is released, in fact, the RST pin is high, the button pressed, still high level, Therefore, this circuit can not trigger a level of the Jump trigger reset interrupt.
Proof of the above statement: The current reset button can not trigger the reset, I knocked out the C11, the entire circuit is not affected.
I found a STM32F4 chip. The correct reset circuit, the following analysis of its principle: after power on, reset pin level from low to high, the chip began to work, when the button is pressed, VCC3.3 to GND to achieve the path, the voltage is R7 divided, so that the reset pin becomes low, release the button, reset to high level again. Due to the C7 charge discharge capability, the voltage mutation is actually avoided.
From for notes (Wiz)
Learn about the error of reset circuit and the principle of reset circuit in the circuit diagram of Wang Small board
