High speed analogread & digitalwrite?

i working on project device 2 receives light pattern device 1. device 2 needs give feedback of led light within 1us. currently, going use arduino our platform. however, according reference, analogread function , digitalwrite function takes 100us , 8us separately, way long our system.

so there way can shorten digitalwrite , analogread function within 500ns?

any appreciated,
terry

quote

within 500ns?

you can write constant value constant port in 125ns, using "direct port manipulation", adc requires 65 microseconds full-accuracy conversion., , there's no way you're going read external adc in 1us.  (now, if sampling time larger, can start conversion, , maybe read actual register , digitalwrite within microsecond, difficult (the avr arduino execute fewer 16 instructions per microsecond...)
it's impossible using arduino functions.

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