33 lines
1.0 KiB
Python
33 lines
1.0 KiB
Python
from functools import partial
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from migen.fhdl import structure as f
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from migen.bus import wishbone
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from migen.corelogic import timeline
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class Inst:
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def __init__(self, adr_width, rd_timing):
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self.bus = wishbone.Slave("norflash")
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d = partial(f.declare_signal, self)
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d("adr", f.BV(adr_width-1))
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d("d", f.BV(16))
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d("oe_n")
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d("we_n")
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d("ce_n")
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d("rst_n")
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self.timeline = timeline.Inst(self.bus.cyc_i & self.bus.stb_i,
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[(0, [f.Assign(self.adr, f.Cat(0, self.bus.adr_i[2:adr_width]))]),
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(rd_timing, [
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f.Assign(self.bus.dat_o[16:], self.d),
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f.Assign(self.adr, f.Cat(1, self.bus.adr_i[2:adr_width]))]),
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(2*rd_timing, [
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f.Assign(self.bus.dat_o[:16], self.d),
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f.Assign(self.bus.ack_o, 1)]),
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(2*rd_timing+1, [
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f.Assign(self.bus.ack_o, 0)])])
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def get_fragment(self):
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comb = [f.Assign(self.oe_n, 0), f.Assign(self.we_n, 1),
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f.Assign(self.ce_n, 0), f.Assign(self.rst_n, 1)]
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return f.Fragment(comb, pads={self.adr, self.d, self.oe_n, self.we_n, self.ce_n, self.rst_n}) \
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+ self.timeline.get_fragment()
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