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Utils.hpp
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Utils.hpp
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// samplerate code by Frank Boesing
// https://forum.pjrc.com/threads/38753-Discussion-about-a-simple-way-to-change-the-sample-rate
void setI2SFreq(int freq) {
typedef struct {
uint8_t mult;
uint16_t div;
} __attribute__((__packed__)) tmclk;
const int numfreqs = 14;
const int samplefreqs[numfreqs] = { 8000, 11025, 16000, 22050, 32000, 44100, static_cast<int>(44117.64706) , 48000, 88200, static_cast<int>(44117.64706 * 2), 96000, 176400, static_cast<int>(44117.64706 * 4), 192000};
#if (F_PLL==16000000)
const tmclk clkArr[numfreqs] = {{16, 125}, {148, 839}, {32, 125}, {145, 411}, {64, 125}, {151, 214}, {12, 17}, {96, 125}, {151, 107}, {24, 17}, {192, 125}, {127, 45}, {48, 17}, {255, 83} };
#elif (F_PLL==72000000)
const tmclk clkArr[numfreqs] = {{32, 1125}, {49, 1250}, {64, 1125}, {49, 625}, {128, 1125}, {98, 625}, {8, 51}, {64, 375}, {196, 625}, {16, 51}, {128, 375}, {249, 397}, {32, 51}, {185, 271} };
#elif (F_PLL==96000000)
const tmclk clkArr[numfreqs] = {{8, 375}, {73, 2483}, {16, 375}, {147, 2500}, {32, 375}, {147, 1250}, {2, 17}, {16, 125}, {147, 625}, {4, 17}, {32, 125}, {151, 321}, {8, 17}, {64, 125} };
#elif (F_PLL==120000000)
const tmclk clkArr[numfreqs] = {{32, 1875}, {89, 3784}, {64, 1875}, {147, 3125}, {128, 1875}, {205, 2179}, {8, 85}, {64, 625}, {89, 473}, {16, 85}, {128, 625}, {178, 473}, {32, 85}, {145, 354} };
#elif (F_PLL==144000000)
const tmclk clkArr[numfreqs] = {{16, 1125}, {49, 2500}, {32, 1125}, {49, 1250}, {64, 1125}, {49, 625}, {4, 51}, {32, 375}, {98, 625}, {8, 51}, {64, 375}, {196, 625}, {16, 51}, {128, 375} };
#elif (F_PLL==180000000)
const tmclk clkArr[numfreqs] = {{46, 4043}, {49, 3125}, {73, 3208}, {98, 3125}, {183, 4021}, {196, 3125}, {16, 255}, {128, 1875}, {107, 853}, {32, 255}, {219, 1604}, {214, 853}, {64, 255}, {219, 802} };
#elif (F_PLL==192000000)
const tmclk clkArr[numfreqs] = {{4, 375}, {37, 2517}, {8, 375}, {73, 2483}, {16, 375}, {147, 2500}, {1, 17}, {8, 125}, {147, 1250}, {2, 17}, {16, 125}, {147, 625}, {4, 17}, {32, 125} };
#elif (F_PLL==216000000)
const tmclk clkArr[numfreqs] = {{32, 3375}, {49, 3750}, {64, 3375}, {49, 1875}, {128, 3375}, {98, 1875}, {8, 153}, {64, 1125}, {196, 1875}, {16, 153}, {128, 1125}, {226, 1081}, {32, 153}, {147, 646} };
#elif (F_PLL==240000000)
const tmclk clkArr[numfreqs] = {{16, 1875}, {29, 2466}, {32, 1875}, {89, 3784}, {64, 1875}, {147, 3125}, {4, 85}, {32, 625}, {205, 2179}, {8, 85}, {64, 625}, {89, 473}, {16, 85}, {128, 625} };
#endif
for (int f = 0; f < numfreqs; f++) {
if ( freq == samplefreqs[f] ) {
while (I2S0_MCR & I2S_MCR_DUF) ;
I2S0_MDR = I2S_MDR_FRACT((clkArr[f].mult - 1)) | I2S_MDR_DIVIDE((clkArr[f].div - 1));
return;
}
}
}