What is Maximum input frequency that we can give at external interrupt pin of STM32F756?

[jagdish2]

In a project, want to generate few control signals at a frequency of 5 - 10MHz. with proper synchronization. So i thought of connecting a dedicated crystal at external interrupt pin.

Am using STM32F756. Is this controller capable enough to accept the interrupts at a frequency of 10MHz.

Jagdish

[waclawek.jan]

Yes. Look at the Pulse width of external signals detected by the EXTI controller parameter in the datasheet.

JW

[jagdish2]

Hi, Tx for reply.

i referred datasheet, Couldn't found the details in it.

pls guide. As i have a routine for external interrupt iSR. Wan to know frequency at which it will fail.

[waclawek.jan]

The EXTI will catch pulses shorter than the value under that parameter, i.e. 10ns

However, as far as *frequency* is concerned, it's more about the execution time of your interrupt routine, and that's your code, I can't tell how long it takes. Measure it (either using the debug timer, or using the classical "toggle-pin, then measure on oscilloscope/logic analyzer" method).

JW

[waclawek.jan]

[jagdish2]

It means that if I have an ISR takes 0.1 usec to execute, i can provide the frequency more than 10 MHz. Do i need to configure GPIO to achieve this?

[Tesla DeLorean]

Most rational people don't interrupt the processor in the MHz range. Use the TIM to capture/count pulses, use prescale settings to decimate interrupt loading, or DMA to capture values.

The saturation point of the processor is determined by the cost of stacking and unstacking context, and how much code you run to perform the task and clear the source.