spi: use misoc SPIMachine, closes #314

This commit is contained in:
Robert Jördens 2016-08-25 22:14:26 +02:00
parent 91b59cd584
commit 051e6e0447
1 changed files with 1 additions and 156 deletions

View File

@ -1,163 +1,8 @@
from itertools import product from itertools import product
from migen import * from migen import *
from migen.genlib.fsm import FSM, NextState
from misoc.interconnect import wishbone from misoc.interconnect import wishbone
from misoc.cores.spi.core import SPIMachine
class SPIClockGen(Module):
def __init__(self, width):
self.load = Signal(width)
self.bias = Signal() # bias this clock phase to longer times
self.edge = Signal()
self.clk = Signal(reset=1)
cnt = Signal.like(self.load)
bias = Signal()
zero = Signal()
self.comb += [
zero.eq(cnt == 0),
self.edge.eq(zero & ~bias),
]
self.sync += [
If(zero,
bias.eq(0),
).Else(
cnt.eq(cnt - 1),
),
If(self.edge,
cnt.eq(self.load[1:]),
bias.eq(self.load[0] & (self.clk ^ self.bias)),
self.clk.eq(~self.clk),
)
]
class SPIRegister(Module):
def __init__(self, width):
self.data = Signal(width)
self.o = Signal()
self.i = Signal()
self.lsb = Signal()
self.shift = Signal()
self.sample = Signal()
self.comb += [
self.o.eq(Mux(self.lsb, self.data[0], self.data[-1])),
]
self.sync += [
If(self.shift,
If(self.lsb,
self.data[:-1].eq(self.data[1:]),
).Else(
self.data[1:].eq(self.data[:-1]),
)
),
If(self.sample,
If(self.lsb,
self.data[-1].eq(self.i),
).Else(
self.data[0].eq(self.i),
)
)
]
class SPIBitCounter(Module):
def __init__(self, width):
self.n_read = Signal(width)
self.n_write = Signal(width)
self.read = Signal()
self.write = Signal()
self.done = Signal()
self.comb += [
self.write.eq(self.n_write != 0),
self.read.eq(self.n_read != 0),
self.done.eq(~(self.write | self.read)),
]
self.sync += [
If(self.write,
self.n_write.eq(self.n_write - 1),
).Elif(self.read,
self.n_read.eq(self.n_read - 1),
)
]
class SPIMachine(Module):
def __init__(self, data_width, clock_width, bits_width):
ce = CEInserter()
self.submodules.cg = ce(SPIClockGen(clock_width))
self.submodules.reg = ce(SPIRegister(data_width))
self.submodules.bits = ce(SPIBitCounter(bits_width))
self.div_write = Signal.like(self.cg.load)
self.div_read = Signal.like(self.cg.load)
self.clk_phase = Signal()
self.start = Signal()
self.cs = Signal()
self.oe = Signal()
self.done = Signal()
# # #
fsm = CEInserter()(FSM("IDLE"))
self.submodules += fsm
fsm.act("IDLE",
If(self.start,
If(self.clk_phase,
NextState("WAIT"),
).Else(
NextState("SETUP"),
)
)
)
fsm.act("SETUP",
self.reg.sample.eq(1),
NextState("HOLD"),
)
fsm.act("HOLD",
If(self.bits.done & ~self.start,
If(self.clk_phase,
NextState("IDLE"),
).Else(
NextState("WAIT"),
)
).Else(
self.reg.shift.eq(~self.start),
NextState("SETUP"),
)
)
fsm.act("WAIT",
If(self.bits.done,
NextState("IDLE"),
).Else(
NextState("SETUP"),
)
)
write0 = Signal()
self.sync += [
If(self.cg.edge & self.reg.shift,
write0.eq(self.bits.write),
)
]
self.comb += [
self.cg.ce.eq(self.start | self.cs | ~self.cg.edge),
If(self.bits.write | ~self.bits.read,
self.cg.load.eq(self.div_write),
).Else(
self.cg.load.eq(self.div_read),
),
self.cg.bias.eq(self.clk_phase),
fsm.ce.eq(self.cg.edge),
self.cs.eq(~fsm.ongoing("IDLE")),
self.reg.ce.eq(self.cg.edge),
self.bits.ce.eq(self.cg.edge & self.reg.sample),
self.done.eq(self.cg.edge & self.bits.done & fsm.ongoing("HOLD")),
self.oe.eq(write0 | self.bits.write),
]
class SPIMaster(Module): class SPIMaster(Module):