i am new to the STM32-stuff and i have little project. Actually i need a tool to test camera shutters from 30s to 1/8000s. I have desiged a kind of sensor board in Kicad. I link to use two sensor for horizontal traveling shutter and two for vertical travelling shutters. There is a switch to choose one or the other kind. In any case there are two channels, one per phototransistor. They are interfaced to a 74HC132 to convert any wave to a clear square signal.
But how can i meter the time the signal is high at a STM32? I have a STM32F401CCU6 development board at hand.
Use a timer with 4 channels going to pins for maximum flexibility.
Timer free runs and overflow say 1 MHz timer overflow at 65535. Connect first income signal to channel 1 and 2 to capture the timer timestamp of rise, and fall edge same for second incoming signal on ch 3 and 4. You will need interrupt on falling edge and you 16 bit substract fall value minus rise value to know the high duration. There are more tricky ways, better to start from the basic.
