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  decode IIC
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SCL: -------|------_|__-__|__-__|___---_|_----|
SDA: -------|---____|_____|_---_|_---___|__---|

state: IDLE

      idle    start    0     1   restart  stop


stat

while SCL is HIGH, if SDA changes then START, RESTART, STOP

when SDA -_  and SCL = HIGH then START
when SDA _-  and SCL = HIGH then STOP

need to look for clock pulse , sample SDA on _- and -_ edges and if same emit 1 or 0
when SCL -_

when SCL -_  and SDA = HIGH then 1
when SCL -_  and SDA = LOW  then 0

states: STOPPED, CLK,