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vendor.xilinx_spartan6: implement DDR I/O buffers and inverters.

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This commit is contained in:
Jean-François Nguyen 2019-06-12 16:56:05 +02:00 committed by whitequark
parent 2566747061
commit 412781e0c3
1 changed files with 149 additions and 87 deletions
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236
nmigen/vendor/xilinx_spartan6.py vendored
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@ -126,150 +126,212 @@ class XilinxSpartan6Platform(TemplatedPlatform):
""" """
] ]
def _get_dff(self, m, clk, d, q): def _get_xdr_buffer(self, m, pin, i_invert=None, o_invert=None):
# SDR I/O is performed by packing a flip-flop into the pad IOB. def get_dff(clk, d, q):
for bit in range(len(q)): # SDR I/O is performed by packing a flip-flop into the pad IOB.
_q = Signal() for bit in range(len(q)):
_q.attrs["IOB"] = "TRUE" _q = Signal()
m.submodules += Instance("FDCE", _q.attrs["IOB"] = "TRUE"
i_C=clk, m.submodules += Instance("FDCE",
i_CE=Const(1), i_C=clk,
i_CLR=Const(0), i_CE=Const(1),
i_D=d[bit], i_CLR=Const(0),
o_Q=_q, i_D=d[bit],
) o_Q=_q,
m.d.comb += q[bit].eq(_q) )
m.d.comb += q[bit].eq(_q)
def get_iddr(clk, d, q0, q1):
for bit in range(len(q0)):
m.submodules += Instance("IDDR2",
p_DDR_ALIGNMENT="C0",
p_SRTYPE="ASYNC",
p_INIT_Q0=0, p_INIT_Q1=0,
i_C0=clk, i_C1=~clk,
i_CE=Const(1),
i_S=Const(0), i_R=Const(0),
i_D=d[bit],
o_Q0=q0[bit], o_Q1=q1[bit]
)
def get_oddr(clk, d0, d1, q):
for bit in range(len(q)):
m.submodules += Instance("ODDR2",
p_DDR_ALIGNMENT="C0",
p_SRTYPE="ASYNC",
p_INIT=0,
i_C0=clk, i_C1=~clk,
i_CE=Const(1),
i_S=Const(0), i_R=Const(0),
i_D0=d0[bit], i_D1=d1[bit],
o_Q=q[bit]
)
def get_i_inverter(y, invert):
if invert is None:
return y
else:
a = Signal.like(y, name_suffix="_x{}".format(1 if invert else 0))
for bit in range(len(y)):
m.submodules += Instance("LUT1",
p_INIT=0b01 if invert else 0b10,
i_I0=a[bit],
o_O=y[bit]
)
return a
def get_o_inverter(a, invert):
if invert is None:
return a
else:
y = Signal.like(a, name_suffix="_x{}".format(1 if invert else 0))
for bit in range(len(a)):
m.submodules += Instance("LUT1",
p_INIT=0b01 if invert else 0b10,
i_I0=a[bit],
o_O=y[bit]
)
return y
if "i" in pin.dir:
if pin.xdr < 2:
pin_i = get_i_inverter(pin.i, i_invert)
elif pin.xdr == 2:
pin_i0 = get_i_inverter(pin.i0, i_invert)
pin_i1 = get_i_inverter(pin.i1, i_invert)
if "o" in pin.dir:
if pin.xdr < 2:
pin_o = get_o_inverter(pin.o, o_invert)
elif pin.xdr == 2:
pin_o0 = get_o_inverter(pin.o0, o_invert)
pin_o1 = get_o_inverter(pin.o1, o_invert)
i = Signal(pin.width, name="{}_xdr_i".format(pin.name))
o = Signal(pin.width, name="{}_xdr_o".format(pin.name))
oe = Signal(1, name="{}_xdr_oe".format(pin.name))
if pin.xdr == 0:
if "i" in pin.dir:
m.d.comb += pin_i.eq(i)
if "o" in pin.dir:
m.d.comb += o.eq(pin_o)
if pin.dir in ("oe", "io"):
m.d.comb += oe.eq(pin.oe)
elif pin.xdr == 1:
if "i" in pin.dir:
get_dff(pin.i_clk, i, pin_i)
if "o" in pin.dir:
get_dff(pin.o_clk, pin_o, o)
if pin.dir in ("oe", "io"):
get_dff(pin.o_clk, pin.oe, oe)
elif pin.xdr == 2:
if "i" in pin.dir:
# Re-register first input before it enters fabric. This allows both inputs to
# enter fabric on the same clock edge, and adds one cycle of latency.
i0_ff = Signal.like(pin_i0, name_suffix="_ff")
get_dff(pin.i_clk, i0_ff, pin_i0)
get_iddr(pin.i_clk, i, i0_ff, pin_i1)
if "o" in pin.dir:
get_oddr(pin.o_clk, pin_o0, pin_o1, o)
if pin.dir in ("oe", "io"):
get_dff(pin.o_clk, pin.oe, oe)
else:
assert False
return (i, o, oe)
def get_input(self, pin, port, attrs, invert): def get_input(self, pin, port, attrs, invert):
assert not invert
self._check_feature("single-ended input", pin, attrs, self._check_feature("single-ended input", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, i_invert=True if invert else None)
self._get_dff(m, pin.i_clk, port, pin.i) m.d.comb += i.eq(port)
else:
m.d.comb += pin.i.eq(port)
return m return m
def get_output(self, pin, port, attrs, invert): def get_output(self, pin, port, attrs, invert):
assert not invert
self._check_feature("single-ended output", pin, attrs, self._check_feature("single-ended output", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, o_invert=True if invert else None)
self._get_dff(m, pin.o_clk, pin.o, port) m.d.comb += port.eq(o)
else:
m.d.comb += port.eq(pin.o)
return m return m
def get_tristate(self, pin, port, attrs, invert): def get_tristate(self, pin, port, attrs, invert):
assert not invert
self._check_feature("single-ended tristate", pin, attrs, self._check_feature("single-ended tristate", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, o_invert=True if invert else None)
o_ff = Signal.like(pin.o, name="{}_ff".format(pin.o.name))
oe_ff = Signal.like(pin.oe, name="{}_ff".format(pin.oe.name))
self._get_dff(m, pin.o_clk, pin.o, o_ff)
self._get_dff(m, pin.o_clk, pin.oe, oe_ff)
for bit in range(len(port)): for bit in range(len(port)):
m.submodules += Instance("OBUFT", m.submodules += Instance("OBUFT",
i_T=~(oe_ff if pin.xdr == 1 else pin.oe), i_T=~oe,
i_I=o_ff[bit] if pin.xdr == 1 else pin.o[bit], i_I=o[bit],
o_O=port[bit] o_O=port[bit]
) )
return m return m
def get_input_output(self, pin, port, attrs, invert): def get_input_output(self, pin, port, attrs, invert):
assert not invert
self._check_feature("single-ended input/output", pin, attrs, self._check_feature("single-ended input/output", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, i_invert=True if invert else None,
o_ff = Signal.like(pin.o, name="{}_ff".format(pin.o.name)) o_invert=True if invert else None)
oe_ff = Signal.like(pin.oe, name="{}_ff".format(pin.oe.name))
i_ff = Signal.like(pin.i, name="{}_ff".format(pin.i.name))
self._get_dff(m, pin.o_clk, pin.o, o_ff)
self._get_dff(m, pin.o_clk, pin.oe, oe_ff)
self._get_dff(m, pin.i_clk, i_ff, pin.i)
for bit in range(len(port)): for bit in range(len(port)):
m.submodules += Instance("IOBUF", m.submodules += Instance("IOBUF",
i_T=~(oe_ff if pin.xdr == 1 else pin.oe), i_T=~oe,
i_I=o_ff[bit] if pin.xdr == 1 else pin.o[bit], i_I=o[bit],
o_O=i_ff[bit] if pin.xdr == 1 else pin.i[bit], o_O=i[bit],
io_IO=port[bit] io_IO=port[bit]
) )
return m return m
def get_diff_input(self, pin, p_port, n_port, attrs, invert): def get_diff_input(self, pin, p_port, n_port, attrs, invert):
assert not invert
self._check_feature("differential input", pin, attrs, self._check_feature("differential input", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, i_invert=True if invert else None)
i_ff = Signal.like(pin.i, name="{}_ff".format(pin.i.name))
self._get_dff(m, pin.i_clk, i_ff, pin.i)
for bit in range(len(p_port)): for bit in range(len(p_port)):
m.submodules += Instance("IBUFDS", m.submodules += Instance("IBUFDS",
i_I=p_port[bit], i_I=p_port[bit], i_IB=n_port[bit],
i_IB=n_port[bit], o_O=i[bit]
o_O=i_ff[bit] if pin.xdr == 1 else pin.i[bit]
) )
return m return m
def get_diff_output(self, pin, p_port, n_port, attrs, invert): def get_diff_output(self, pin, p_port, n_port, attrs, invert):
assert not invert
self._check_feature("differential output", pin, attrs, self._check_feature("differential output", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, o_invert=True if invert else None)
o_ff = Signal.like(pin.o, name="{}_ff".format(pin.o.name))
self._get_dff(m, pin.o_clk, pin.o, o_ff)
for bit in range(len(p_port)): for bit in range(len(p_port)):
m.submodules += Instance("OBUFDS", m.submodules += Instance("OBUFDS",
o_O=p_port[bit], i_I=o[bit],
o_OB=n_port[bit], o_O=p_port[bit], o_OB=n_port[bit]
i_I=o_ff[bit] if pin.xdr == 1 else pin.o[bit]
) )
return m return m
def get_diff_tristate(self, pin, p_port, n_port, attrs, invert): def get_diff_tristate(self, pin, p_port, n_port, attrs, invert):
assert not invert
self._check_feature("differential tristate", pin, attrs, self._check_feature("differential tristate", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, o_invert=True if invert else None)
o_ff = Signal.like(pin.o, name="{}_ff".format(pin.o.name))
oe_ff = Signal.like(pin.oe, name="{}_ff".format(pin.oe.name))
self._get_dff(m, pin.o_clk, pin.o, o_ff)
self._get_dff(m, pin.o_clk, pin.oe, oe_ff)
for bit in range(len(p_port)): for bit in range(len(p_port)):
m.submodules += Instance("OBUFTDS", m.submodules += Instance("OBUFTDS",
i_T=~(oe_ff if pin.xdr == 1 else pin.oe), i_T=~oe,
i_I=o_ff[bit] if pin.xdr == 1 else pin.o[bit], i_I=o[bit],
o_O=p_port[bit], o_O=p_port[bit], o_OB=n_port[bit]
o_OB=n_port[bit]
) )
return m return m
def get_diff_input_output(self, pin, p_port, n_port, attrs, invert): def get_diff_input_output(self, pin, p_port, n_port, attrs, invert):
assert not invert
self._check_feature("differential input/output", pin, attrs, self._check_feature("differential input/output", pin, attrs,
valid_xdrs=(0, 1), valid_attrs=True) valid_xdrs=(0, 1, 2), valid_attrs=True)
m = Module() m = Module()
if pin.xdr == 1: i, o, oe = self._get_xdr_buffer(m, pin, i_invert=True if invert else None,
o_ff = Signal.like(pin.o, name="{}_ff".format(pin.o.name)) o_invert=True if invert else None)
oe_ff = Signal.like(pin.oe, name="{}_ff".format(pin.oe.name))
i_ff = Signal.like(pin.i, name="{}_ff".format(pin.i.name))
self._get_dff(m, pin.o_clk, pin.o, o_ff)
self._get_dff(m, pin.o_clk, pin.oe, oe_ff)
self._get_dff(m, pin.i_clk, i_ff, pin.i)
for bit in range(len(p_port)): for bit in range(len(p_port)):
m.submodules += Instance("IOBUFDS", m.submodules += Instance("IOBUFDS",
i_T=~(oe_ff if pin.xdr == 1 else pin.oe), i_T=~oe,
i_I=o_ff[bit] if pin.xdr == 1 else pin.o[bit], i_I=o[bit],
o_O=i_ff[bit] if pin.xdr == 1 else pin.i[bit], o_O=i[bit],
io_IO=p_port[bit], io_IO=p_port[bit], io_IOB=n_port[bit]
io_IOB=n_port[bit]
) )
return m return m