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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 | // SPDX-License-Identifier: GPL-2.0+ /* * Program for finding M & N values for DPLLs * To be run on Host PC * * (C) Copyright 2010 * Texas Instruments, <www.ti.com> * * Aneesh V <aneesh@ti.com> */ #include <stdlib.h> #include <stdio.h> typedef unsigned int u32; #define MAX_N 127 /* * get_m_n_optimized() - Finds optimal DPLL multiplier(M) and divider(N) * values based on the reference frequency, required output frequency, * maximum tolerance for output frequency etc. * * target_freq_khz - output frequency required in KHz * ref_freq_khz - reference(input) frequency in KHz * m - pointer to computed M value * n - pointer to computed N value * tolerance_khz - tolerance for the output frequency. When the algorithm * succeeds in finding vialble M and N values the corresponding output * frequency will be in the range: * [target_freq_khz - tolerance_khz, target_freq_khz] * * Formula: * Fdpll = (2 * M * Fref) / (N + 1) * * Considerations for lock-time: * - Smaller the N, better lock-time, especially lock-time will be * - For acceptable lock-times: * Fref / (M + 1) >= 1 MHz * * Considerations for power: * - The difference in power for different N values giving the same * output is negligible. So, we optimize for lock-time * * Hard-constraints: * - N can not be greater than 127(7 bit field for representing N) * * Usage: * $ gcc clocks_get_m_n.c * $ ./a.out */ int get_m_n_optimized(u32 target_freq_khz, u32 ref_freq_khz, u32 *M, u32 *N) { u32 freq = target_freq_khz; u32 m_optimal, n_optimal, freq_optimal = 0, freq_old; u32 m, n; n = 1; while (1) { m = target_freq_khz / ref_freq_khz / 2 * n; freq_old = 0; while (1) { freq = ref_freq_khz * 2 * m / n; if (freq > target_freq_khz) { freq = freq_old; m--; break; } m++; freq_old = freq; } if (freq > freq_optimal) { freq_optimal = freq; m_optimal = m; n_optimal = n; } n++; if ((freq_optimal == target_freq_khz) || ((ref_freq_khz / n) < 1000)) { break; } } n--; *M = m_optimal; *N = n_optimal - 1; printf("ref %d m %d n %d target %d locked %d\n", ref_freq_khz, m_optimal, n_optimal - 1, target_freq_khz, freq_optimal); return 0; } void main(void) { u32 m, n; printf("\nMPU - 2000000\n"); get_m_n_optimized(2000000, 12000, &m, &n); get_m_n_optimized(2000000, 13000, &m, &n); get_m_n_optimized(2000000, 16800, &m, &n); get_m_n_optimized(2000000, 19200, &m, &n); get_m_n_optimized(2000000, 26000, &m, &n); get_m_n_optimized(2000000, 27000, &m, &n); get_m_n_optimized(2000000, 38400, &m, &n); printf("\nMPU - 1200000\n"); get_m_n_optimized(1200000, 12000, &m, &n); get_m_n_optimized(1200000, 13000, &m, &n); get_m_n_optimized(1200000, 16800, &m, &n); get_m_n_optimized(1200000, 19200, &m, &n); get_m_n_optimized(1200000, 26000, &m, &n); get_m_n_optimized(1200000, 27000, &m, &n); get_m_n_optimized(1200000, 38400, &m, &n); printf("\nMPU - 1584000\n"); get_m_n_optimized(1584000, 12000, &m, &n); get_m_n_optimized(1584000, 13000, &m, &n); get_m_n_optimized(1584000, 16800, &m, &n); get_m_n_optimized(1584000, 19200, &m, &n); get_m_n_optimized(1584000, 26000, &m, &n); get_m_n_optimized(1584000, 27000, &m, &n); get_m_n_optimized(1584000, 38400, &m, &n); printf("\nCore 1600000\n"); get_m_n_optimized(1600000, 12000, &m, &n); get_m_n_optimized(1600000, 13000, &m, &n); get_m_n_optimized(1600000, 16800, &m, &n); get_m_n_optimized(1600000, 19200, &m, &n); get_m_n_optimized(1600000, 26000, &m, &n); get_m_n_optimized(1600000, 27000, &m, &n); get_m_n_optimized(1600000, 38400, &m, &n); printf("\nPER 1536000\n"); get_m_n_optimized(1536000, 12000, &m, &n); get_m_n_optimized(1536000, 13000, &m, &n); get_m_n_optimized(1536000, 16800, &m, &n); get_m_n_optimized(1536000, 19200, &m, &n); get_m_n_optimized(1536000, 26000, &m, &n); get_m_n_optimized(1536000, 27000, &m, &n); get_m_n_optimized(1536000, 38400, &m, &n); printf("\nIVA 1862000\n"); get_m_n_optimized(1862000, 12000, &m, &n); get_m_n_optimized(1862000, 13000, &m, &n); get_m_n_optimized(1862000, 16800, &m, &n); get_m_n_optimized(1862000, 19200, &m, &n); get_m_n_optimized(1862000, 26000, &m, &n); get_m_n_optimized(1862000, 27000, &m, &n); get_m_n_optimized(1862000, 38400, &m, &n); printf("\nIVA Nitro - 1290000\n"); get_m_n_optimized(1290000, 12000, &m, &n); get_m_n_optimized(1290000, 13000, &m, &n); get_m_n_optimized(1290000, 16800, &m, &n); get_m_n_optimized(1290000, 19200, &m, &n); get_m_n_optimized(1290000, 26000, &m, &n); get_m_n_optimized(1290000, 27000, &m, &n); get_m_n_optimized(1290000, 38400, &m, &n); printf("\nABE 196608 sys clk\n"); get_m_n_optimized(196608, 12000, &m, &n); get_m_n_optimized(196608, 13000, &m, &n); get_m_n_optimized(196608, 16800, &m, &n); get_m_n_optimized(196608, 19200, &m, &n); get_m_n_optimized(196608, 26000, &m, &n); get_m_n_optimized(196608, 27000, &m, &n); get_m_n_optimized(196608, 38400, &m, &n); printf("\nABE 196608 32K\n"); get_m_n_optimized(196608000/4, 32768, &m, &n); printf("\nUSB 1920000\n"); get_m_n_optimized(1920000, 12000, &m, &n); get_m_n_optimized(1920000, 13000, &m, &n); get_m_n_optimized(1920000, 16800, &m, &n); get_m_n_optimized(1920000, 19200, &m, &n); get_m_n_optimized(1920000, 26000, &m, &n); get_m_n_optimized(1920000, 27000, &m, &n); get_m_n_optimized(1920000, 38400, &m, &n); printf("\nCore ES1 1523712\n"); get_m_n_optimized(1524000, 12000, &m, &n); get_m_n_optimized(1524000, 13000, &m, &n); get_m_n_optimized(1524000, 16800, &m, &n); get_m_n_optimized(1524000, 19200, &m, &n); get_m_n_optimized(1524000, 26000, &m, &n); get_m_n_optimized(1524000, 27000, &m, &n); /* exact recommendation for SDPs */ get_m_n_optimized(1523712, 38400, &m, &n); } |