// Decoder
c = rgData.length
var pA = 0 // previuos encoder A value
var cnt = 0 // initial phase/counter
for(var i = 0; i < c; i++){
    fA = 1&(rgData[i]<<0)
    if(fA==1 && pA==0){ // encoder A rising edge
            cnt++
    }
    rgValue[i] = cnt
    rgFlag[i] = 1
    pA = fA
}