Stampede

EXTI Pulse Count Wrong Debug

Symptom

Three pulses on the scope, EVENTS:6 on the terminal. The registers and bit fields are on the Datasheet tab.

Circuit

Block diagram: PS1 vibration sensor drives the PA0 pin of U1, an STM32F4, whose USART1 transmit line runs to a serial console

Pass condition

The bench sends one burst of pulses on PA0 while your program runs. Then USART1 prints one line, EVENTS:<pulses>. A pulse counts from the moment it starts.

Expected output for the small burst: three pulses on PA0, then the line EVENTS colon 3 on the serial console

Notes

Some pulses are spikes, over before the processor can enter a handler.

Related challenges

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