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Showing with 60 additions and 0 deletions.
  1. +60 −0 milkymist/adc/__init__.py
60 milkymist/adc/__init__.py
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+from migen.fhdl.structure import *
+from migen.fhdl.module import Module
+from migen.bank.description import *
+from migen.genlib.misc import optree
+from migen.genlib.cdc import MultiReg
+
+class CounterADC(Module, AutoCSR):
+ def __init__(self, charge, sense, width=24):
+ if not isinstance(sense, collections.Iterable):
+ sense = [sense]
+
+ channels = len(sense)
+
+ self._start_busy = CSR()
+ self._overflow = CSRStatus(channels)
+ self._polarity = CSRStorage()
+
+ count = Signal(width)
+ busy = Signal(channels)
+
+ res = []
+ for i in range(channels):
+ res.append(CSRStatus(width, name="res"+str(i)))
+ setattr(self, "_res"+str(i), res[-1])
+
+ any_busy = Signal()
+ self.comb += [
+ any_busy.eq(optree("|",
+ [busy[i] for i in range(channels)])),
+ self._start_busy.w.eq(any_busy)
+ ]
+
+ carry = Signal()
+
+ self.sync += [
+ If(self._start_busy.re,
+ count.eq(0),
+ busy.eq((1 << channels)-1),
+ self._overflow.status.eq(0),
+ charge.eq(~self._polarity.storage)
+ ).Elif(any_busy,
+ Cat(count, carry).eq(count + 1),
+ If(carry,
+ self._overflow.status.eq(busy),
+ busy.eq(0)
+ )
+ ).Else(
+ charge.eq(self._polarity.storage)
+ )
+ ]
+
+ for i in range(channels):
+ sense_synced = Signal()
+ self.specials += MultiReg(sense[i], sense_synced)
+ self.sync += If(busy[i],
+ If(sense_synced != self._polarity.storage,
+ res[i].status.eq(count),
+ busy[i].eq(0)
+ )
+ )

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