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71 lines
3.1 KiB
71 lines
3.1 KiB
5 years ago
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/* IRLibSAMD21.h
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* Part of IRLib Library for Arduino receiving, decoding, and sending
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* infrared signals. See COPYRIGHT.txt and LICENSE.txt for more information.
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*
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* This type of content is normally stored in IRLibHardware.h but we have
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* moved at her because the SAMD21 support is significantly different than the
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* AVR 8-bit hardware support. Separating it out into a separate file
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* will make it easier to include comments and to maintain the code.
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*/
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/* See IRLibSAMD21.h for details about this implementation.
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*/
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#if defined (__SAMD21G18A__)
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#include "IRLibHardware.h"
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//Save some typing
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#define IR_APD g_APinDescription[IR_SEND_PWM_PIN]
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void initializeSAMD21PWM(uint16_t khz) {
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// Enable the port multiplexer for the PWM channel on pin
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PORT->Group[IR_APD.ulPort].PINCFG[IR_APD.ulPin].bit.PMUXEN = 1;
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// Connect the TCC timer to the port outputs - port pins are paired odd PMUXO and even PMUXE
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// F & E peripherals specify the timers: TCC0, TCC1 and TCC2
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PORT->Group[IR_APD.ulPort].PMUX[IR_APD.ulPin >> 1].reg |= IR_MUX_EF;
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// Feed GCLK0 to TCC0 and TCC1
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REG_GCLK_CLKCTRL = GCLK_CLKCTRL_CLKEN | // Enable GCLK0 to TCC0 and TCC1
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GCLK_CLKCTRL_GEN_GCLK0 | // Select GCLK0
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GCLK_CLKCTRL_ID_TCC0_TCC1; // Feed GCLK0 to TCC0 and TCC1
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syncGCLK; // Wait for synchronization
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// Normal (single slope) PWM operation: timers countinuously count up to PER
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// register value and then is reset to 0
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IR_TCCx->WAVE.reg |= TCC_WAVE_WAVEGEN_NPWM; // Setup single slope PWM on TCCx
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while (IR_TCCx->SYNCBUSY.bit.WAVE); // Wait for synchronization
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// Each timer counts up to a maximum or TOP value set by the PER register,
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// this determines the frequency of the PWM operation.
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uint32_t cc = F_CPU/(khz*1000) - 1;
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IR_TCCx->PER.reg = cc; // Set the frequency of the PWM on IR_TCCx
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while(IR_TCCx->SYNCBUSY.bit.PER);
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// The CCx register value corresponds to the pulsewidth in microseconds (us)
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IR_TCCx->CC[(IR_CCn & 0x03)].reg = cc/3; // Set the duty cycle of the PWM on TCC0 to 33%
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while(IR_TCCx->SYNCBUSY.bit.IR_CCx);
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// Enable IR_TCCx timer but do not turn on PWM yet. Will turn it on later.
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IR_TCCx->CTRLA.reg |= TCC_CTRLA_PRESCALER_DIV1; // Divide GCLK0 by 1
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while (IR_TCCx->SYNCBUSY.bit.ENABLE);
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IR_TCCx->CTRLA.reg &= ~TCC_CTRLA_ENABLE; //initially off will turn on later
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while (IR_TCCx->SYNCBUSY.bit.ENABLE);
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}
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/*
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* Setup the 50 microsecond timer hardware interrupt for the IRrecv class.
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*/
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void initializeSAMD21timerInterrupt(void) {
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GCLK->CLKCTRL.reg = (uint16_t)(GCLK_CLKCTRL_CLKEN |
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GCLK_CLKCTRL_GEN_GCLK0 |
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GCLK_CLKCTRL_ID(IR_GCM));
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syncGCLK;
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IR_TCx->COUNT16.CTRLA.reg &= ~TC_CTRLA_ENABLE;
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syncTC;
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IR_TCx->COUNT16.CTRLA.reg = TC_CTRLA_SWRST;
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while (IR_TCx->COUNT16.CTRLA.bit.SWRST);
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IR_TCx->COUNT16.CTRLA.reg |= TC_CTRLA_MODE_COUNT16;
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IR_TCx->COUNT16.CTRLA.reg |= TC_CTRLA_WAVEGEN_MFRQ;
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IR_TCx->COUNT16.CC[0].reg = F_CPU/(1000000/USEC_PER_TICK) - 1;
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syncTC;
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}
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#endif
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