teensy-audio/utility/imxrt_hw.cpp

/* Audio Library for Teensy 3.X
 * Copyright (c) 2019, Paul Stoffregen, paul@pjrc.com
 *
 * Development of this audio library was funded by PJRC.COM, LLC by sales of
 * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
 * open source software by purchasing Teensy or other PJRC products.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice, development funding notice, and this permission
 * notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
/*
 (c) Frank B
*/

#if defined(__IMXRT1052__) || defined(__IMXRT1062__)
#include "imxrt_hw.h"

FLASHMEM
void set_audioClock(int nfact, int32_t nmult, uint32_t ndiv, bool force) // sets PLL4
{
	if (!force && (CCM_ANALOG_PLL_AUDIO & CCM_ANALOG_PLL_AUDIO_ENABLE)) return;

	CCM_ANALOG_PLL_AUDIO = CCM_ANALOG_PLL_AUDIO_BYPASS | CCM_ANALOG_PLL_AUDIO_ENABLE
			     | CCM_ANALOG_PLL_AUDIO_POST_DIV_SELECT(2) // 2: 1/4; 1: 1/2; 0: 1/1
			     | CCM_ANALOG_PLL_AUDIO_DIV_SELECT(nfact);

	CCM_ANALOG_PLL_AUDIO_NUM   = nmult & CCM_ANALOG_PLL_AUDIO_NUM_MASK;
	CCM_ANALOG_PLL_AUDIO_DENOM = ndiv & CCM_ANALOG_PLL_AUDIO_DENOM_MASK;
	
	CCM_ANALOG_PLL_AUDIO &= ~CCM_ANALOG_PLL_AUDIO_POWERDOWN;//Switch on PLL
	while (!(CCM_ANALOG_PLL_AUDIO & CCM_ANALOG_PLL_AUDIO_LOCK)) {}; //Wait for pll-lock
	
	const int div_post_pll = 1; // other values: 2,4
	CCM_ANALOG_MISC2 &= ~(CCM_ANALOG_MISC2_DIV_MSB | CCM_ANALOG_MISC2_DIV_LSB);
	if(div_post_pll>1) CCM_ANALOG_MISC2 |= CCM_ANALOG_MISC2_DIV_LSB;
	if(div_post_pll>3) CCM_ANALOG_MISC2 |= CCM_ANALOG_MISC2_DIV_MSB;
	
	CCM_ANALOG_PLL_AUDIO &= ~CCM_ANALOG_PLL_AUDIO_BYPASS;//Disable Bypass
}

#endif