External Interrupt

[Mstfsy]

I am applying the circuit in the picture I uploaded and when I touch the pin with my hand or touch it with a metal piece, the external break pin is triggered spontaneously. Please help me.

[Tesla DeLorean]

What's the question here?

STM32Cube_FW_F1_V1.8.3\Projects\STM32VL-Discovery\Examples\GPIO\GPIO_EXTI\Src\main.c

[Mstfsy]

How can I solve this problem?

[Tesla DeLorean]

Touch what, where?

You touch the input side of the H11L1 part? It triggers the STM32F1 side EXTI? Is a pulse visible on the PA0, say triggering a scope or logic analyzer?

https://www.digikey.com/en/products/detail/everlight-electronics-co-ltd/H11L1/2691156

[Mstfsy]

When I touch the H11L1 output pin or pa0 pin with a pointed metal, the exti is triggered.

[Tesla DeLorean]

How well are the H11L1 and STM32F103 grounds bonded? Is this a PCB or proto-board?

[Mstfsy]

I am using the STM32F103C8T6 Blue Pill board and I am feeding H11L1 through the 3.3V and GND pins on the board. I am also feeding the board through the 5V pin on the board. I think the ground is OK.

[xisco]

If you use a blue pill, I assume that you use a protoboard or dupont cables.

In the two cases, there is a high risk of bad connections, and it seems that resistor R1 or ground has a problem on its connections, leaving PA0-WKUP on an indeterminate state.

The schematic seems ok

[Mstfsy]

I checked that all VSSA pins of STM32F103C8T6 reach GND. I disconnected H11L1 and connected PA0 pin with a cable directly to 3.3V then GND and the problem persisted.