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stm32f407 exti latency

Question asked by dani.d on Jun 24, 2015
Latest reply on Jun 25, 2015 by dani.d
i am trying to communicate with ata device (via 40 pin ata interface) from my f407. with no prior knowledge to how the ata signals timing is, i used my logic sniffer to see the timing constraint. the strobes (for read/write) signals is in average 100-150ns. And after couple days trying to decode the sniffing result into ata commands/data, i found out that the data valid is within the strobe signal itself.

i've setup my projects to toggle data (write data) at the bus in exti handler of read strobe. seeing the sniffing result, i can not really determine which strobe is triggering the exti, and thus i can not measure the exti latency. but i can see the toggling data doesn't take same time to showed at the bus. after days trying to figure out, i kind of lost here. i started to think that the 407 won't be fast enough to serve within 100-150ns window, not to say have time to output the data to the bus. i've seen on a forum, someone measured toggling data latency in interrupt as about 165ns.

in that 100-150ns windows, i actually have to decode 5 lines of input. thus reading them, and switch case them, and output the data. someone can tell me if this is even possible? or am i wasting time using the f407 to do the job?