1 /* 2 * Program for finding M & N values for DPLLs 3 * To be run on Host PC 4 * 5 * (C) Copyright 2010 6 * Texas Instruments, <www.ti.com> 7 * 8 * Aneesh V <aneesh@ti.com> 9 * 10 * See file CREDITS for list of people who contributed to this 11 * project. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License as 15 * published by the Free Software Foundation; either version 2 of 16 * the License, or (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 * 23 * You should have received a copy of the GNU General Public License 24 * along with this program; if not, write to the Free Software 25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 26 * MA 02111-1307 USA 27 */ 28 #include <stdlib.h> 29 #include <stdio.h> 30 typedef unsigned int u32; 31 #define MAX_N 127 32 33 /* 34 * get_m_n_optimized() - Finds optimal DPLL multiplier(M) and divider(N) 35 * values based on the reference frequency, required output frequency, 36 * maximum tolerance for output frequency etc. 37 * 38 * target_freq_khz - output frequency required in KHz 39 * ref_freq_khz - reference(input) frequency in KHz 40 * m - pointer to computed M value 41 * n - pointer to computed N value 42 * tolerance_khz - tolerance for the output frequency. When the algorithm 43 * succeeds in finding vialble M and N values the corresponding output 44 * frequency will be in the range: 45 * [target_freq_khz - tolerance_khz, target_freq_khz] 46 * 47 * Formula: 48 * Fdpll = (2 * M * Fref) / (N + 1) 49 * 50 * Considerations for lock-time: 51 * - Smaller the N, better lock-time, especially lock-time will be 52 * - For acceptable lock-times: 53 * Fref / (M + 1) >= 1 MHz 54 * 55 * Considerations for power: 56 * - The difference in power for different N values giving the same 57 * output is negligible. So, we optimize for lock-time 58 * 59 * Hard-constraints: 60 * - N can not be greater than 127(7 bit field for representing N) 61 * 62 * Usage: 63 * $ gcc clocks_get_m_n.c 64 * $ ./a.out 65 */ 66 int get_m_n_optimized(u32 target_freq_khz, u32 ref_freq_khz, u32 *M, u32 *N) 67 { 68 u32 freq = target_freq_khz; 69 u32 m_optimal, n_optimal, freq_optimal = 0, freq_old; 70 u32 m, n; 71 n = 1; 72 while (1) { 73 m = target_freq_khz / ref_freq_khz / 2 * n; 74 freq_old = 0; 75 while (1) { 76 freq = ref_freq_khz * 2 * m / n; 77 if (freq > target_freq_khz) { 78 freq = freq_old; 79 m--; 80 break; 81 } 82 m++; 83 freq_old = freq; 84 } 85 if (freq > freq_optimal) { 86 freq_optimal = freq; 87 m_optimal = m; 88 n_optimal = n; 89 } 90 n++; 91 if ((freq_optimal == target_freq_khz) || 92 ((ref_freq_khz / n) < 1000)) { 93 break; 94 } 95 } 96 n--; 97 *M = m_optimal; 98 *N = n_optimal - 1; 99 printf("ref %d m %d n %d target %d locked %d\n", ref_freq_khz, 100 m_optimal, n_optimal - 1, target_freq_khz, freq_optimal); 101 return 0; 102 } 103 104 void main(void) 105 { 106 u32 m, n; 107 printf("\nMPU - 2000000\n"); 108 get_m_n_optimized(2000000, 12000, &m, &n); 109 get_m_n_optimized(2000000, 13000, &m, &n); 110 get_m_n_optimized(2000000, 16800, &m, &n); 111 get_m_n_optimized(2000000, 19200, &m, &n); 112 get_m_n_optimized(2000000, 26000, &m, &n); 113 get_m_n_optimized(2000000, 27000, &m, &n); 114 get_m_n_optimized(2000000, 38400, &m, &n); 115 116 printf("\nMPU - 1200000\n"); 117 get_m_n_optimized(1200000, 12000, &m, &n); 118 get_m_n_optimized(1200000, 13000, &m, &n); 119 get_m_n_optimized(1200000, 16800, &m, &n); 120 get_m_n_optimized(1200000, 19200, &m, &n); 121 get_m_n_optimized(1200000, 26000, &m, &n); 122 get_m_n_optimized(1200000, 27000, &m, &n); 123 get_m_n_optimized(1200000, 38400, &m, &n); 124 125 printf("\nMPU - 1584000\n"); 126 get_m_n_optimized(1584000, 12000, &m, &n); 127 get_m_n_optimized(1584000, 13000, &m, &n); 128 get_m_n_optimized(1584000, 16800, &m, &n); 129 get_m_n_optimized(1584000, 19200, &m, &n); 130 get_m_n_optimized(1584000, 26000, &m, &n); 131 get_m_n_optimized(1584000, 27000, &m, &n); 132 get_m_n_optimized(1584000, 38400, &m, &n); 133 134 printf("\nCore 1600000\n"); 135 get_m_n_optimized(1600000, 12000, &m, &n); 136 get_m_n_optimized(1600000, 13000, &m, &n); 137 get_m_n_optimized(1600000, 16800, &m, &n); 138 get_m_n_optimized(1600000, 19200, &m, &n); 139 get_m_n_optimized(1600000, 26000, &m, &n); 140 get_m_n_optimized(1600000, 27000, &m, &n); 141 get_m_n_optimized(1600000, 38400, &m, &n); 142 143 printf("\nPER 1536000\n"); 144 get_m_n_optimized(1536000, 12000, &m, &n); 145 get_m_n_optimized(1536000, 13000, &m, &n); 146 get_m_n_optimized(1536000, 16800, &m, &n); 147 get_m_n_optimized(1536000, 19200, &m, &n); 148 get_m_n_optimized(1536000, 26000, &m, &n); 149 get_m_n_optimized(1536000, 27000, &m, &n); 150 get_m_n_optimized(1536000, 38400, &m, &n); 151 152 printf("\nIVA 1862000\n"); 153 get_m_n_optimized(1862000, 12000, &m, &n); 154 get_m_n_optimized(1862000, 13000, &m, &n); 155 get_m_n_optimized(1862000, 16800, &m, &n); 156 get_m_n_optimized(1862000, 19200, &m, &n); 157 get_m_n_optimized(1862000, 26000, &m, &n); 158 get_m_n_optimized(1862000, 27000, &m, &n); 159 get_m_n_optimized(1862000, 38400, &m, &n); 160 161 printf("\nIVA Nitro - 1290000\n"); 162 get_m_n_optimized(1290000, 12000, &m, &n); 163 get_m_n_optimized(1290000, 13000, &m, &n); 164 get_m_n_optimized(1290000, 16800, &m, &n); 165 get_m_n_optimized(1290000, 19200, &m, &n); 166 get_m_n_optimized(1290000, 26000, &m, &n); 167 get_m_n_optimized(1290000, 27000, &m, &n); 168 get_m_n_optimized(1290000, 38400, &m, &n); 169 170 printf("\nABE 196608 sys clk\n"); 171 get_m_n_optimized(196608, 12000, &m, &n); 172 get_m_n_optimized(196608, 13000, &m, &n); 173 get_m_n_optimized(196608, 16800, &m, &n); 174 get_m_n_optimized(196608, 19200, &m, &n); 175 get_m_n_optimized(196608, 26000, &m, &n); 176 get_m_n_optimized(196608, 27000, &m, &n); 177 get_m_n_optimized(196608, 38400, &m, &n); 178 179 printf("\nABE 196608 32K\n"); 180 get_m_n_optimized(196608000/4, 32768, &m, &n); 181 182 printf("\nUSB 1920000\n"); 183 get_m_n_optimized(1920000, 12000, &m, &n); 184 get_m_n_optimized(1920000, 13000, &m, &n); 185 get_m_n_optimized(1920000, 16800, &m, &n); 186 get_m_n_optimized(1920000, 19200, &m, &n); 187 get_m_n_optimized(1920000, 26000, &m, &n); 188 get_m_n_optimized(1920000, 27000, &m, &n); 189 get_m_n_optimized(1920000, 38400, &m, &n); 190 191 printf("\nCore ES1 1523712\n"); 192 get_m_n_optimized(1524000, 12000, &m, &n); 193 get_m_n_optimized(1524000, 13000, &m, &n); 194 get_m_n_optimized(1524000, 16800, &m, &n); 195 get_m_n_optimized(1524000, 19200, &m, &n); 196 get_m_n_optimized(1524000, 26000, &m, &n); 197 get_m_n_optimized(1524000, 27000, &m, &n); 198 199 /* exact recommendation for SDPs */ 200 get_m_n_optimized(1523712, 38400, &m, &n); 201 202 } 203