--- /dev/null
+/*
+ * 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>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#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 tolerance_khz)
+{
+ u32 min_freq = target_freq_khz - tolerance_khz;
+ u32 max_freq = target_freq_khz;
+ u32 freq, freq_old;
+ *n = 1;
+ while (1) {
+ *m = min_freq / ref_freq_khz / 2 * (*n) ;
+ freq_old = 0;
+ while (1) {
+ freq = ref_freq_khz * 2 * (*m) / (*n);
+ if (abs(target_freq_khz - freq_old) <=
+ abs(target_freq_khz - freq)) {
+ freq = freq_old;
+ (*m)--;
+ break;
+ }
+ (*m)++;
+ freq_old = freq;
+ }
+ if (freq >= min_freq && freq <= max_freq)
+ break;
+ (*n)++;
+ if ((*n) > MAX_N + 1) {
+ printf("ref %d m %d n %d target %d : ",
+ ref_freq_khz, *m, *n, target_freq_khz);
+ printf("can not find m & n - please consider"
+ " increasing tolerance\n");
+ return -1;
+ }
+ }
+ (*n)--;
+ printf("ref %d m %d n %d target %d locked %d\n",
+ ref_freq_khz, *m, *n, target_freq_khz, freq);
+ if ((ref_freq_khz / (*n + 1)) < 1000) {
+ printf("\tREFCLK - CLKINP/(N+1) is less than 1 MHz - less than"
+ " ideal, locking time will be high!\n");
+ }
+ return 0;
+}
+
+void main(void)
+{
+ u32 m, n;
+ printf("\nMPU - 2000000\n");
+ get_m_n_optimized(2000000, 12000, &m, &n, 0);
+ get_m_n_optimized(2000000, 13000, &m, &n, 0);
+ get_m_n_optimized(2000000, 16800, &m, &n, 800);
+ get_m_n_optimized(2000000, 19200, &m, &n, 0);
+ get_m_n_optimized(2000000, 26000, &m, &n, 0);
+ get_m_n_optimized(2000000, 27000, &m, &n, 0);
+ get_m_n_optimized(2000000, 38400, &m, &n, 0);
+
+ printf("\nMPU - 1200000\n");
+ get_m_n_optimized(1200000, 12000, &m, &n, 0);
+ get_m_n_optimized(1200000, 13000, &m, &n, 0);
+ get_m_n_optimized(1200000, 16800, &m, &n, 800);
+ get_m_n_optimized(1200000, 19200, &m, &n, 0);
+ get_m_n_optimized(1200000, 26000, &m, &n, 0);
+ get_m_n_optimized(1200000, 27000, &m, &n, 0);
+ get_m_n_optimized(1200000, 38400, &m, &n, 0);
+
+ printf("\nMPU - 1584000\n");
+ get_m_n_optimized(1584000, 12000, &m, &n, 0);
+ get_m_n_optimized(1584000, 13000, &m, &n, 0);
+ get_m_n_optimized(1584000, 16800, &m, &n, 400);
+ get_m_n_optimized(1584000, 19200, &m, &n, 0);
+ get_m_n_optimized(1584000, 26000, &m, &n, 0);
+ get_m_n_optimized(1584000, 27000, &m, &n, 0);
+ get_m_n_optimized(1584000, 38400, &m, &n, 0);
+
+ printf("\nCore 1600000\n");
+ get_m_n_optimized(1600000, 12000, &m, &n, 0);
+ get_m_n_optimized(1600000, 13000, &m, &n, 0);
+ get_m_n_optimized(1600000, 16800, &m, &n, 200);
+ get_m_n_optimized(1600000, 19200, &m, &n, 0);
+ get_m_n_optimized(1600000, 26000, &m, &n, 0);
+ get_m_n_optimized(1600000, 27000, &m, &n, 0);
+ get_m_n_optimized(1600000, 38400, &m, &n, 0);
+
+ printf("\nPER 1536000\n");
+ get_m_n_optimized(1536000, 12000, &m, &n, 0);
+ get_m_n_optimized(1536000, 13000, &m, &n, 0);
+ get_m_n_optimized(1536000, 16800, &m, &n, 0);
+ get_m_n_optimized(1536000, 19200, &m, &n, 0);
+ get_m_n_optimized(1536000, 26000, &m, &n, 0);
+ get_m_n_optimized(1536000, 27000, &m, &n, 0);
+ get_m_n_optimized(1536000, 38400, &m, &n, 0);
+
+ printf("\nIVA 1862000\n");
+ get_m_n_optimized(1862000, 12000, &m, &n, 0);
+ get_m_n_optimized(1862000, 13000, &m, &n, 0);
+ get_m_n_optimized(1862000, 16800, &m, &n, 0);
+ get_m_n_optimized(1862000, 19200, &m, &n, 900);
+ get_m_n_optimized(1862000, 26000, &m, &n, 0);
+ get_m_n_optimized(1862000, 27000, &m, &n, 0);
+ get_m_n_optimized(1862000, 38400, &m, &n, 800);
+
+ printf("\nABE 196608 sys clk\n");
+ get_m_n_optimized(196608, 12000, &m, &n, 700);
+ get_m_n_optimized(196608, 13000, &m, &n, 200);
+ get_m_n_optimized(196608, 16800, &m, &n, 700);
+ get_m_n_optimized(196608, 19200, &m, &n, 400);
+ get_m_n_optimized(196608, 26000, &m, &n, 200);
+ get_m_n_optimized(196608, 27000, &m, &n, 900);
+ get_m_n_optimized(196608, 38400, &m, &n, 0);
+
+ printf("\nABE 196608 32K\n");
+ get_m_n_optimized(196608000/4, 32768, &m, &n, 0);
+
+ printf("\nUSB 1920000\n");
+ get_m_n_optimized(1920000, 12000, &m, &n, 0);
+ get_m_n_optimized(1920000, 13000, &m, &n, 0);
+ get_m_n_optimized(1920000, 16800, &m, &n, 0);
+ get_m_n_optimized(1920000, 19200, &m, &n, 0);
+ get_m_n_optimized(1920000, 26000, &m, &n, 0);
+ get_m_n_optimized(1920000, 27000, &m, &n, 0);
+ get_m_n_optimized(1920000, 38400, &m, &n, 0);
+
+ printf("\nCore ES1 1523712\n");
+ get_m_n_optimized(1524000, 12000, &m, &n, 100);
+ get_m_n_optimized(1524000, 13000, &m, &n, 0);
+ get_m_n_optimized(1524000, 16800, &m, &n, 0);
+ get_m_n_optimized(1524000, 19200, &m, &n, 0);
+ get_m_n_optimized(1524000, 26000, &m, &n, 0);
+ get_m_n_optimized(1524000, 27000, &m, &n, 0);
+
+ /* exact recommendation for SDPs */
+ get_m_n_optimized(1523712, 38400, &m, &n, 0);
+
+}
projects / u-boot / blobdiff