btidey wrote:Not feasible in my view to do this directly on an ESP8266. You are talking 2-3 CPU clocks even at 160MHz. The ESP8266 also has a slower internal IO bus and you have some uncertain latency into getting into an ISR if you were going that route.
You should explain a bit more on what you are trying to measure to see if there are other approaches.
What i'm going to do is two way ranging. While i can calculate the delays of the radio modules i need a way to precisely measure the time durations of sending and receiving signals. That's why i thought to use the interrupts. The radio modules will output the demodulated signals after they received them, throught the interrupts on the mcu i want to measure the arrival times of these signals. I saw that with teensy 3.6 it's possible as it has a timer which will timestamp the signals. But programming and developing an standalone product with an arm cortex is much difficult for me. That's the reason why i'm researching the ESP chip.