hidaka sato / QEI_simple

simple QEI library. no return speed, only return angle.

Dependents:   WRS_mechanamu_test

QEI.cpp@0:bffc97496048, 2018-08-20 (annotated)

Committer:
sgrsn
Date:
Mon Aug 20 04:54:24 2018 +0000
Revision:
0:bffc97496048
Child:
1:6fa863d09d45
Child:
2:62821df48957
simple QEI

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sgrsn 0:bffc97496048 1 #include "QEI.h"
sgrsn 0:bffc97496048 2
sgrsn 0:bffc97496048 3 const int8_t encodeTable[] = {0, -1, 1, 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 1, -1, 0 };
sgrsn 0:bffc97496048 4
sgrsn 0:bffc97496048 5 QEI::QEI(PinName A, PinName B, int ppr) : channelA(A), channelB(B)
sgrsn 0:bffc97496048 6 {
sgrsn 0:bffc97496048 7 channelA.rise(this, &QEI::encode);
sgrsn 0:bffc97496048 8 channelB.rise(this, &QEI::encode);
sgrsn 0:bffc97496048 9 channelA.fall(this, &QEI::encode);
sgrsn 0:bffc97496048 10 channelB.fall(this, &QEI::encode);
sgrsn 0:bffc97496048 11 _ppr = ppr;
sgrsn 0:bffc97496048 12 currState = 0;
sgrsn 0:bffc97496048 13 prevState = 0;
sgrsn 0:bffc97496048 14 position = 0;
sgrsn 0:bffc97496048 15 }
sgrsn 0:bffc97496048 16
sgrsn 0:bffc97496048 17 float QEI::getAngle()
sgrsn 0:bffc97496048 18 {
sgrsn 0:bffc97496048 19 return float(position) * 360.0/(_ppr*4.0);
sgrsn 0:bffc97496048 20 }
sgrsn 0:bffc97496048 21
sgrsn 0:bffc97496048 22 void QEI::encode(void)
sgrsn 0:bffc97496048 23 {
sgrsn 0:bffc97496048 24 int8_t chanA = channelA.read();
sgrsn 0:bffc97496048 25 int8_t chanB = channelB.read();
sgrsn 0:bffc97496048 26 currState = chanA | (chanB << 1);
sgrsn 0:bffc97496048 27
sgrsn 0:bffc97496048 28 if (prevState != currState) {
sgrsn 0:bffc97496048 29 position += encodeTable[currState | (prevState<<2)];
sgrsn 0:bffc97496048 30 prevState = currState;
sgrsn 0:bffc97496048 31 }
sgrsn 0:bffc97496048 32 }