Jared Baxter / Mbed 2 deprecated Impedance_Fast_Circuitry_print_V_I

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Dependencies:   mbed-dsp mbed

Fork of Impedance_Fast_Circuitry by Jared Baxter

quadrature.cpp@45:d591d138cdeb, 2015-01-31 (annotated)

Committer:
timmey9
Date:
Sat Jan 31 07:25:52 2015 +0000
Revision:
45:d591d138cdeb
Quadrature decoder is working.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
timmey9 45:d591d138cdeb 1 #include "quadrature.h"
timmey9 45:d591d138cdeb 2
timmey9 45:d591d138cdeb 3 void quad_init() {
timmey9 45:d591d138cdeb 4
timmey9 45:d591d138cdeb 5 // Enable clock for FTM2
timmey9 45:d591d138cdeb 6 SIM_SCGC3 |= SIM_SCGC3_FTM2_MASK; // there are two of them for some reason
timmey9 45:d591d138cdeb 7 SIM_SCGC6 |= SIM_SCGC6_FTM2_MASK; //
timmey9 45:d591d138cdeb 8
timmey9 45:d591d138cdeb 9 // Enable clock for PortB
timmey9 45:d591d138cdeb 10 SIM_SCGC5 |= SIM_SCGC5_PORTB_MASK;
timmey9 45:d591d138cdeb 11
timmey9 45:d591d138cdeb 12 //enable the counter
timmey9 45:d591d138cdeb 13 FTM2_MODE |= FTM_MODE_WPDIS_MASK; // unlock write protection on certain FTM bits and registers
timmey9 45:d591d138cdeb 14 FTM2_MODE |= FTM_MODE_FTMEN_MASK;
timmey9 45:d591d138cdeb 15
timmey9 45:d591d138cdeb 16 //enable the counter to run in the BDM mode
timmey9 45:d591d138cdeb 17 FTM2_CONF |= FTM_CONF_BDMMODE(3);
timmey9 45:d591d138cdeb 18
timmey9 45:d591d138cdeb 19 //load the Modulo register and counter initial value
timmey9 45:d591d138cdeb 20 FTM2_MOD = 4095;
timmey9 45:d591d138cdeb 21 FTM2_CNTIN = 0;
timmey9 45:d591d138cdeb 22
timmey9 45:d591d138cdeb 23 //configuring FTM for quadrature mode
timmey9 45:d591d138cdeb 24 FTM2_QDCTRL |= FTM_QDCTRL_QUADEN_MASK; // enable Quadrature decoding
timmey9 45:d591d138cdeb 25 FTM2_QDCTRL &= ~FTM_QDCTRL_QUADMODE_MASK; // select phase A and phase B decoding mode (this is what the angle encoder uses)
timmey9 45:d591d138cdeb 26
timmey9 45:d591d138cdeb 27 // start the timer clock, source is the external clock
timmey9 45:d591d138cdeb 28 FTM2_SC |= FTM_SC_CLKS(3);
timmey9 45:d591d138cdeb 29
timmey9 45:d591d138cdeb 30 //configuring the input pins:
timmey9 45:d591d138cdeb 31 PORTB_PCR18 = PORT_PCR_MUX(6); // FTM2_QD_PHA (PTB18) ALT6
timmey9 45:d591d138cdeb 32 PORTB_PCR19 = PORT_PCR_MUX(6); // FTM2_QD_PHB (PTB19) ALT6
timmey9 45:d591d138cdeb 33
timmey9 45:d591d138cdeb 34 // Enable write protection
timmey9 45:d591d138cdeb 35 FTM2_MODE |= FTM_MODE_WPDIS_MASK; // Lock write protection on certain FTM bits and registers
timmey9 45:d591d138cdeb 36
timmey9 45:d591d138cdeb 37 }
timmey9 45:d591d138cdeb 38
timmey9 45:d591d138cdeb 39 int32_t quad_read() {
timmey9 45:d591d138cdeb 40 //int32_t* temp = (int32_t*)0x4003a004;
timmey9 45:d591d138cdeb 41 return FTM2_CNT; // this is the register with the counter in it.
timmey9 45:d591d138cdeb 42 }