96 lines
3.3 KiB
C++
96 lines
3.3 KiB
C++
/*
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* Copyright (C) OpenTX
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*
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* Based on code named
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* th9x - http://code.google.com/p/th9x
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* er9x - http://code.google.com/p/er9x
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* gruvin9x - http://code.google.com/p/gruvin9x
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*
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* License GPLv2: http://www.gnu.org/licenses/gpl-2.0.html
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include "opentx.h"
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// Start TIMER3 for input capture
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inline void start_timer3()
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{
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Tc *ptc ;
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// Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
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PMC->PMC_PCER0 |= 0x04000000L ; // Enable peripheral clock to TC3
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ptc = TC1 ; // Tc block 1 (TC3-5)
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ptc->TC_BCR = 0 ; // No sync
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ptc->TC_BMR = 2 ;
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ptc->TC_CHANNEL[0].TC_CMR = 0x00000000 ; // Capture mode
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ptc->TC_CHANNEL[0].TC_CMR = 0x00090005 ; // 0000 0000 0000 1001 0000 0000 0000 0101, XC0, A rise, b fall
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ptc->TC_CHANNEL[0].TC_CCR = 5 ; // Enable clock and trigger it (may only need trigger)
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configure_pins( PIO_PC23, PIN_PERIPHERAL | PIN_INPUT | PIN_PER_B | PIN_PORTC | PIN_PULLUP ) ;
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NVIC_SetPriority( TC3_IRQn, 14 ) ; // Low priority interrupt
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NVIC_EnableIRQ(TC3_IRQn) ;
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ptc->TC_CHANNEL[0].TC_IER = TC_IER0_LDRAS ;
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}
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// Start Timer4 to provide 0.5uS clock for input capture
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void start_timer4()
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{
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Tc *ptc ;
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uint32_t timer ;
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timer = Master_frequency / (2*2000000) ; // MCK/2 and 2MHz
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// Enable peripheral clock TC0 = bit 23 thru TC5 = bit 28
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PMC->PMC_PCER0 |= 0x08000000L ; // Enable peripheral clock to TC4
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ptc = TC1 ; // Tc block 1 (TC3-5)
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ptc->TC_BCR = 0 ; // No sync
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ptc->TC_BMR = 0 ;
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ptc->TC_CHANNEL[1].TC_CMR = 0x00008000 ; // Waveform mode
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ptc->TC_CHANNEL[1].TC_RC = timer ;
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ptc->TC_CHANNEL[1].TC_RA = timer >> 1 ;
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ptc->TC_CHANNEL[1].TC_CMR = 0x0009C000 ; // 0000 0000 0000 1001 1100 0000 0100 0000
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// MCK/2, set @ RA, Clear @ RC waveform
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ptc->TC_CHANNEL[1].TC_CCR = 5 ; // Enable clock and trigger it (may only need trigger)
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}
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// Timer3 used for PPM_IN pulse width capture. Counter running at 16MHz / 8 = 2MHz
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// equating to one count every half millisecond. (2 counts = 1ms). Control channel
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// count delta values thus can range from about 1600 to 4400 counts (800us to 2200us),
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// corresponding to a PPM signal in the range 0.8ms to 2.2ms (1.5ms at center).
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// (The timer is free-running and is thus not reset to zero at each capture interval.)
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// Timer 4 generates the 2MHz clock to clock Timer 3
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extern "C" void TC3_IRQHandler() //capture ppm in at 2MHz
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{
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uint32_t status = TC1->TC_CHANNEL[0].TC_SR;
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if (status & TC_SR0_LDRAS) {
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uint16_t capture = TC1->TC_CHANNEL[0].TC_RA ;
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captureTrainerPulses(capture);
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}
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}
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void init_trainer_capture()
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{
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PIOC->PIO_PER = PIO_PC22;
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start_timer4() ;
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start_timer3() ;
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}
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void stop_trainer_capture()
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{
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PIOC->PIO_PDR = PIO_PC22;
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TC1->TC_CHANNEL[0].TC_IDR = TC_IDR0_LDRAS ;
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NVIC_DisableIRQ(TC3_IRQn) ;
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}
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