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-rw-r--r--src/scripts/clock-graph.5c148
-rw-r--r--src/scripts/clock.5c40
-rw-r--r--src/scripts/fix.5c14
-rw-r--r--src/scripts/tv.5c128
4 files changed, 330 insertions, 0 deletions
diff --git a/src/scripts/clock-graph.5c b/src/scripts/clock-graph.5c
new file mode 100644
index 00000000..98500e1e
--- /dev/null
+++ b/src/scripts/clock-graph.5c
@@ -0,0 +1,148 @@
+autoload Cairo;
+import Cairo;
+library "examples/sort.5c";
+import Sort;
+
+int width = 1000, height = 200;
+
+int min = 0xffffffff;
+int max = 0;
+
+int max_clocks = 1000;
+int[4][max_clocks] clocks;
+int[4] clock_count = {0...};
+
+int[4] p2vals = {5,10,7,14};
+
+cairo_t cr = Cairo::new(width, height);
+
+void calc_p2(int p2i)
+{
+ int p2 = p2vals[p2i];
+ int min_p, max_p;
+
+ clocks[p2i] = (int [max_clocks]){0...};
+
+ if (p2 == 7 || p2 == 14) {
+ /* LVDS */
+ min_p = 7;
+ max_p = 98;
+ } else {
+ /* SDVO/DAC */
+ min_p = 5;
+ max_p = 80;
+ }
+
+ for (int m1 = 10; m1 <= 20; m1++) {
+ for (int m2 = 5; m2 <= 9; m2++) {
+ for (int n = 3; n <= 8; n++) {
+ for (int p1 = 1; p1 <= 8; p1++) {
+ int ref = 96000000;
+ int m = 5 * (m1 + 2) + (m2 + 2);
+ int p = p1 * p2;
+ int vco = floor(ref * m / (n + 2));
+ int clock = floor(vco / p);
+
+ if (p < min_p || p > max_p)
+ continue;
+ if (m < 70 || m > 120)
+ continue;
+ if (m2 > m1)
+ continue; /* won't happen */
+ if (vco < 1400000000 ||
+ vco > 2800000000)
+ continue;
+
+/*
+ printf("clock: %d (%d,%d), %d, "
+ "(%d,%d)\n",
+ floor(clock / 1000),
+ m1, m2, n, p1, p2);
+*/
+
+ clocks[p2i][clock_count[p2i]] = clock;
+ clock_count[p2i]++;
+ }
+ }
+ }
+ }
+}
+
+bool sort_p2(poly a, poly b)
+{
+ return a > b;
+}
+
+int min_rate = 25000 * 1000;
+int max_rate = 200000 * 1000;
+
+real scale_x(real clock)
+{
+ int min_x = 75, max_x = width - 50;
+
+ real frac = (clock - min_rate) / (max_rate - min_rate);
+
+ return min_x + frac * (max_x - min_x);
+}
+
+for (p2i = 0; p2i < dim(p2vals); p2i++) {
+ int p2 = p2vals[p2i];
+ calc_p2(p2i);
+ /*qsort(&p2vals[p2i], sort_p2);*/
+
+ switch (p2) {
+ case 5:
+ set_source_rgb(cr, 1,0,0);
+ break;
+ case 10:
+ set_source_rgb(cr, 0,1,0);
+ break;
+ case 7:
+ set_source_rgb(cr, 0,0,1);
+ break;
+ case 14:
+ set_source_rgb(cr, 0,0,0);
+ break;
+ }
+ for (int i = 0; i < clock_count[p2i]; i++) {
+ int clock = clocks[p2i][i];
+ real xpos;
+
+ if (clock < min_rate || clock > max_rate)
+ continue;
+
+ xpos = scale_x(clock);
+ move_to(cr, xpos, p2i / (dim(p2vals) + 1) * height);
+ line_to(cr, xpos, (p2i + 1) / (dim(p2vals) + 1) * height);
+ stroke(cr);
+ }
+
+ set_source_rgb(cr, 0, 0, 0);
+ string p2label = sprintf("p2 = %d", p2);
+ move_to(cr, 5, (p2i + .5) / (dim(p2vals) + 1) * height + 4);
+ show_text(cr, p2label);
+}
+
+void label_clock(real clock) {
+ real center_x = scale_x(clock);
+ string label = sprintf("%d", floor((clock + 500) / 1000000));
+ text_extents_t e = text_extents(cr, label);
+ real left_x = center_x - e.x_advance / 2;
+ save(cr);
+ move_to(cr, left_x, height - 20);
+ show_text(cr, label);
+ restore(cr);
+}
+
+label_clock(min_rate);
+label_clock(max_rate);
+label_clock(140 * 1000 * 1000);
+label_clock(115 * 1000 * 1000);
+label_clock(100 * 1000 * 1000);
+label_clock(82 * 1000 * 1000);
+
+string xlabel = "Clock in Mhz";
+text_extents_t e = text_extents(cr, xlabel);
+move_to(cr, width / 2 - e.x_advance / 2, height - 5);
+show_text(cr, xlabel);
+sleep(10);
diff --git a/src/scripts/clock.5c b/src/scripts/clock.5c
new file mode 100644
index 00000000..8ee9d90e
--- /dev/null
+++ b/src/scripts/clock.5c
@@ -0,0 +1,40 @@
+int p2 = 14;
+int min_p, max_p;
+
+if (p2 == 7 || p2 == 14) {
+ /* LVDS */
+ min_p = 7;
+ max_p = 98;
+} else {
+ /* SDVO/DAC */
+ min_p = 5;
+ max_p = 80;
+}
+
+for (int m1 = 10; m1 <= 20; m1++) {
+ for (int m2 = 5; m2 <= 9; m2++) {
+ for (int n = 3; n <= 8; n++) {
+ for (int p1 = 1; p1 <= 8; p1++) {
+ int ref = 96000000;
+ int m = 5 * (m1 + 2) + (m2 + 2);
+ int p = p1 * p2;
+ int vco = floor(ref * m / (n + 2));
+ int clock = floor(vco / p);
+
+ if (p < min_p || p > max_p)
+ continue;
+ if (m < 70 || m > 120)
+ continue;
+ if (m2 > m1)
+ continue; /* won't happen */
+ if (vco < 1400000000 ||
+ vco > 2800000000)
+ continue;
+
+ printf("clock: %d (%d,%d),%d,(%d,%d)\n",
+ floor(clock / 1000),
+ m1, m2, n, p1, p2);
+ }
+ }
+ }
+}
diff --git a/src/scripts/fix.5c b/src/scripts/fix.5c
new file mode 100644
index 00000000..b758a433
--- /dev/null
+++ b/src/scripts/fix.5c
@@ -0,0 +1,14 @@
+/*
+ * Convert CSC fix point values to floats
+ */
+
+real fixval (int fix)
+{
+ int exp = fix >> 9;
+ int mant = fix & ((1 << 9) - 1);
+ real ret;
+ if (exp == 0x7)
+ return 1.0;
+ ret = (2 ** -exp) * mant / (1 << 9);
+ return ret;
+}
diff --git a/src/scripts/tv.5c b/src/scripts/tv.5c
new file mode 100644
index 00000000..b4a2ba61
--- /dev/null
+++ b/src/scripts/tv.5c
@@ -0,0 +1,128 @@
+/*
+ * tv.5c
+ *
+ * Compute tv encoder subcarrier dda constants
+ *
+ * The TV encoder subcarrier must be set precisely to the
+ * required frequency or the cumulative phase errors will be
+ * quite visible in the output. To accomplish this, the TV encoder
+ * has a complex circuit that takes a fixed clock, generated by the PLL
+ * and generates a precise subcarrier clock from that using the following
+ * formula:
+ *
+ * subcarrier = pixel_clock * (S1 + (S2 + (S3/Z3)) / Z2) / 4096
+ *
+ * Careful selection of the constants will provide the necessarily
+ * precise clock.
+ *
+ * In the code below, S1 is represented by dda1, S2/Z2 by dda2 and S3/Z3
+ * by dda3.
+ */
+
+typedef struct {
+ int step;
+ int size;
+} term_t;
+
+/*
+ * Find the approximation closest, but no larger than 'v', where
+ * 0 <= v < 1, and the result denominator must be less than 30000.
+ */
+term_t approx (rational v)
+{
+ rational best_dist = 1.0;
+ term_t best;
+
+ for (int den = 20000; den < 30000; den++)
+ {
+ int num = floor (v * den);
+ term_t approx = { step = num, size = den };
+ rational dist = v - approx.step/approx.size;
+ if (dist >= 0 && dist < best_dist)
+ {
+ best_dist = dist;
+ best = approx;
+ }
+ }
+ return best;
+}
+
+typedef struct {
+ rational subcarrier;
+ rational pixel;
+ rational result;
+ term_t dda1;
+ term_t dda2;
+ term_t dda3;
+} dda;
+
+/*
+ * Compute the dda constants for the given pixel clock and
+ * desired subcarrier frequency
+ */
+
+dda find_dda (rational pixel, rational subcarrier)
+{
+ dda d;
+
+ d.subcarrier = subcarrier;
+ d.pixel = pixel;
+
+ rational dda1 = subcarrier / pixel * 4096;
+ d.dda1 = (term_t) { step = floor (dda1), size = 4096 };
+
+ rational dda2 = dda1 - d.dda1.step;
+ d.dda2 = approx (dda2);
+
+ rational dda3 = dda2 * d.dda2.size - d.dda2.step;
+ d.dda3 = approx (dda3);
+
+ /* Compute the resulting pixel clock to compare */
+ d.result = d.pixel * (d.dda1.step +
+ (d.dda2.step + d.dda3.step/d.dda3.size) /
+ d.dda2.size) / d.dda1.size;
+ return d;
+}
+
+/*
+ * Print out the computed constants
+ */
+void print_dda (dda d)
+{
+ printf ("\t/* desired %9.7f actual %9.7f clock %g */\n",
+ d.subcarrier, d.result, d.pixel);
+ printf ("\t.dda1_inc\t= %6d,\n", d.dda1.step);
+ printf ("\t.dda2_inc\t= %6d,\t.dda2_size\t= %6d,\n",
+ d.dda2.step, d.dda2.step != 0 ? d.dda2.size : 0);
+ printf ("\t.dda3_inc\t= %6d,\t.dda3_size\t= %6d,\n",
+ d.dda3.step, d.dda3.step != 0 ? d.dda3.size : 0);
+}
+
+/*
+ * These are all of the required subcarrier frequencies
+ */
+rational[] subcarriers = {
+ /* these are the values we use; for some reason, this generates
+ * a more stable image (at least for NTSC) */
+ 3.580, 4.434, 3.582, 3.576, 4.430,
+
+ /* these are the values pulled out of the various specs */
+ 3.579545, 4.433618, 3.582056, 3.575611, 4.433618
+};
+
+/*
+ * We fix the pixel clock to a value which the hardware can
+ * generate exactly
+ */
+rational pixel = 107.520;
+
+void main ()
+{
+ for (int i = 0; i < dim(subcarriers); i++)
+ {
+ dda d = find_dda (pixel, subcarriers[i]);
+ print_dda (d);
+ }
+}
+
+main ();
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