mirror of https://github.com/arendst/Tasmota.git
47 lines
1.5 KiB
C++
47 lines
1.5 KiB
C++
/*
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AudioOutputI2SNoDAC
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Audio player using SW delta-sigma to generate "analog" on I2S data
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Copyright (C) 2017 Earle F. Philhower, III
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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 as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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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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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _AUDIOOUTPUTI2SNODAC_H
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#define _AUDIOOUTPUTI2SNODAC_H
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#include "AudioOutputI2S.h"
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class AudioOutputI2SNoDAC : public AudioOutputI2S
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{
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public:
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AudioOutputI2SNoDAC(int port = 0);
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virtual ~AudioOutputI2SNoDAC() override;
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virtual bool ConsumeSample(int16_t sample[2]) override;
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bool SetOversampling(int os);
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protected:
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virtual int AdjustI2SRate(int hz) override { return hz * oversample/32; }
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uint8_t oversample;
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void DeltaSigma(int16_t sample[2], uint32_t dsBuff[4]);
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typedef int32_t fixed24p8_t;
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enum {fixedPosValue=0x007fff00}; /* 24.8 of max-signed-int */
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fixed24p8_t lastSamp; // Last sample value
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fixed24p8_t cumErr; // Running cumulative error since time began
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};
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#endif
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