add pll calculation helper

git-svn-id: https://svn.openpcd.org:2342/trunk@17 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

2 files changed, 29 insertions, 0 deletions

diff --git a/openpcd/pll.pl b/openpcd/pll.pl
new file mode 100755
index 0000000..2acb222
--- /dev/null
+++ b/openpcd/pll.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/perl
+
+
+# MCLK = (18.432 / DIV) * MUL = 48.000
+
+my $MCLK = 18432;
+
+my $div;
+my $mul;
+
+for ($div = 1; $div < 256; $div++) {
+	my $tmp = $MCLK / $div;
+	for ($mul = 1; $mul < 2048; $mul++) {
+		my $res = $tmp * $mul;
+		if ($res == 96000) {
+			printf("res=%u, div=%u, tmp=%u, mul=%u\n", 
+				$res, $div, $tmp, $mul);
+		}
+	}
+}
+
+
diff --git a/openpcd/pll.txt b/openpcd/pll.txt
new file mode 100644
index 0000000..d086630
--- /dev/null
+++ b/openpcd/pll.txt
@@ -0,0 +1,7 @@
+MAINCLK = 18.432MHz
+PLLCLK(div=24,mul=125) = 96MHz
+MCLK(divisor 2) = 48MHz
+USB(divisor 2) = 48MHz
+MC_FWR(FWS) = 2 		# 1 flash waitstate
+
+SPCK(SCBR=10) = 4.8MHz		# 5MHz max clock RC632