From 85fbe07b9445973833a7a4735b3cac077d0d0328 Mon Sep 17 00:00:00 2001 From: Sebastien Bourdeauducq Date: Sat, 17 Dec 2011 15:00:11 +0100 Subject: [PATCH] clkfx module --- milkymist/clkfx/__init__.py | 38 +++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 milkymist/clkfx/__init__.py diff --git a/milkymist/clkfx/__init__.py b/milkymist/clkfx/__init__.py new file mode 100644 index 000000000..9eb5600ae --- /dev/null +++ b/milkymist/clkfx/__init__.py @@ -0,0 +1,38 @@ +from fractions import Fraction + +from migen.fhdl.structure import * + +class Inst: + def __init__(self, infreq, outfreq): + declare_signal(self, "clkin") + declare_signal(self, "clkout") + + ratio = Fraction(outfreq)/Fraction(infreq) + appr = ratio.limit_denominator(32) + m = appr.numerator + if m < 2 or m > 32: + raise OverflowError + d = appr.denominator + + in_period = float(Fraction(1000000000)/Fraction(infreq)) + + self._inst = Instance("DCM_SP", + [("CLKFX", self.clkout)], + [("CLKIN", self.clkin), + ("PSEN", BV(1)), + ("RST", BV(1))], + [("CLKDV_DIVIDE", 2.0), + ("CLKFX_DIVIDE", d), + ("CLKFX_MULTIPLY", m), + ("CLKIN_DIVIDE_BY_2", "FALSE"), + ("CLKIN_PERIOD", in_period), + ("CLKOUT_PHASE_SHIFT", "NONE"), + ("CLK_FEEDBACK", "NONE"), + ("DESKEW_ADJUST", "SYSTEM_SYNCHRONOUS"), + ("DUTY_CYCLE_CORRECTION", "TRUE"), + ("PHASE_SHIFT", 0), + ("STARTUP_WAIT", "TRUE")] + ) + + def get_fragment(self): + return Fragment([self._inst.ins["PSEN"].eq(0), self._inst.ins["RST"].eq(0)], instances=[self._inst])