NuBusFPGA/nubus-to-ztex-gateware/nubus_stat.py

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2022-06-04 16:56:41 +00:00
from migen import *
from migen.genlib.fifo import *
from migen.genlib.cdc import BusSynchronizer
import litex
from litex.soc.interconnect import wishbone
class NuBusStat(Module):
def __init__(self, nubus, platform):
self.bus_slv = bus_slv = wishbone.Interface()
read_ctr = Signal(32)
writ_ctr = Signal(32)
self.submodules.sync_read_ctr = BusSynchronizer(width = 32, idomain="nubus", odomain="sys")
self.submodules.sync_writ_ctr = BusSynchronizer(width = 32, idomain="nubus", odomain="sys")
self.comb += [
self.sync_read_ctr.i.eq(nubus.read_ctr),
read_ctr.eq(self.sync_read_ctr.o),
self.sync_writ_ctr.i.eq(nubus.writ_ctr),
writ_ctr.eq(self.sync_writ_ctr.o),
]
self.submodules.wishbone_fsm = wishbone_fsm = FSM(reset_state = "Reset")
wishbone_fsm.act("Reset",
NextValue(bus_slv.ack, 0),
NextState("Idle"))
wishbone_fsm.act("Idle",
If(bus_slv.cyc & bus_slv.stb & bus_slv.we & ~bus_slv.ack, #write
# FIXME: should check for prefix?
#Case(bus_slv.adr[0:10], {
# 0x0: [ NextValue(read_ctr, bus_slv.dat_w[0:32]), ],
# 0x1: [ NextValue(write_ctr, bus_slv.dat_w[0:32]), ],
#}),
NextValue(bus_slv.ack, 1),
).Elif(bus_slv.cyc & bus_slv.stb & ~bus_slv.we & ~bus_slv.ack, #read
Case(bus_slv.adr[0:10], {
0x0: [ NextValue(bus_slv.dat_r, Cat(read_ctr[24:32], read_ctr[16:24], read_ctr[ 8:16], read_ctr[ 0: 8])), ],
0x1: [ NextValue(bus_slv.dat_r, Cat(writ_ctr[24:32], writ_ctr[16:24], writ_ctr[ 8:16], writ_ctr[ 0: 8])), ],
}),
NextValue(bus_slv.ack, 1),
).Else(
NextValue(bus_slv.ack, 0),
)
)