def m_fifo_short(clock, reset, clear,
datain, src_rdy_i, dst_rdy_o,
dataout, src_rdy_o, dst_rdy_i):
wr = Signal(bool(0))
rd = Signal(bool(0))
args = Namespace(width=36, size=16, name='fifo_2clock_cascade')
fbus = FIFOBus(args=args)
# need to update the fbus refernces to reference the Signals in
# the moudule port list (function arguments).
fbus.wr = wr
fbus.wdata = datain
fbus.rd = rd
fbus.rdata = dataout
fbus.clear = clear
@always_comb
def rtl_assign1():
wr.next = src_rdy_i & dst_rdy_o
rd.next = dst_rdy_i & src_rdy_o
@always_comb
def rtl_assign2():
dst_rdy_o.next = not fbus.full
src_rdy_o.next = not fbus.empty
gfifo = m_fifo_fast(clock, reset, fbus)
return rtl_assign1, rtl_assign2, gfifo
def m_fifo_short(clock, reset, clear, datain, src_rdy_i, dst_rdy_o, dataout,
src_rdy_o, dst_rdy_i):
wr = Signal(bool(0))
rd = Signal(bool(0))
args = Namespace(width=36, size=16, name='fifo_2clock_cascade')
fbus = FIFOBus(args=args)
# need to update the fbus refernces to reference the Signals in
# the moudule port list (function arguments).
fbus.wr = wr
fbus.wdata = datain
fbus.rd = rd
fbus.rdata = dataout
@always_comb
def rtl_assign1():
wr.next = src_rdy_i & dst_rdy_o
rd.next = dst_rdy_i & src_rdy_o
@always_comb
def rtl_assign2():
dst_rdy_o.next = not fbus.full
src_rdy_o.next = not fbus.empty
gfifo = m_fifo_fast(clock, reset, fbus)
return rtl_assign1, rtl_assign2, gfifo
def _test():
# @todo: use args.fast, args.use_srl_prim
tbdut = m_fifo_fast(clock, reset, fbus, use_srl_prim=False)
@always(delay(10))
def tbclk():
clock.next = not clock
@instance
def tbstim():
fbus.wdata.next = 0xFE
reset.next = reset.active
yield delay(33)
reset.next = not reset.active
for ii in range(5):
yield clock.posedge
# test the normal cases
for num_bytes in range(1, args.size+1):
# write some bytes
for ii in range(num_bytes):
#print('nbyte %x wdata %x' % (num_bytes, ii))
yield clock.posedge
fbus.wdata.next = ii
fbus.wr.next = True
yield clock.posedge
fbus.wr.next = False
fbus.wdata.next = 0xFE
# if 16 bytes written make sure FIFO is full
yield clock.posedge
if num_bytes == args.size:
assert fbus.full, "FIFO should be full!"
assert not fbus.empty, "FIFO should not be empty"
for ii in range(num_bytes):
fbus.rd.next = True
yield clock.posedge
#print("rdata %x ii %x " % (fbus.rdata, ii))
assert fbus.rvld
assert fbus.rdata == ii, "rdata %x ii %x " % (fbus.rdata, ii)
fbus.rd.next = False
yield clock.posedge
assert fbus.empty
# Test overflows
# Test underflows
# Test write / read same time
raise StopSimulation
return tbdut, tbclk, tbstim
def m_fifo_2clock_cascade(
wclk, # in: write side clock
datain, # in: write data
src_rdy_i, # in:
dst_rdy_o, # out:
space, # out: how many can be written
rclk, # in: read side clock
dataout, # out: read data
src_rdy_o, # out:
dst_rdy_i, # in:
occupied, # out: number in the fifo
reset, # in: system reset
):
wr = Signal(bool(0)) # wr1
#wr2 = Signal(bool(0)) # rd1
wr3 = Signal(bool(0))
rd1 = Signal(bool(0))
rd2 = Signal(bool(0))
rd = Signal(bool(0)) # rd3
ed1 = Signal(bool(1))
args = Namespace(width=36, size=128, name='fifo_2clock_cascade')
fbus2 = FIFOBus(args=args)
args.size = 16
fbus1 = FIFOBus(args=args)
fbus3 = FIFOBus(args=args)
# need to update the fbus refernces to reference the Signals in
# the moudule port list (function arguments).
fbus1.wr = wr
fbus1.wdata = datain
fbus1.rd = rd1
fbus2.wr = rd1
fbus2.wdata = fbus1.rdata
fbus2.rd = rd2
fbus3.wr = wr3
fbus3.wdata = fbus2.rdata
fbus3.rd = rd
fbus3.rdata = dataout
@always_comb
def rtl_assign1():
wr.next = src_rdy_i and dst_rdy_o
rd.next = dst_rdy_i and src_rdy_o
rd1.next = not fbus1.empty and not fbus2.full
rd2.next = not ed1 and not fbus3.full
wr3.next = fbus2.rvld
@always_comb
def rtl_assign2():
dst_rdy_o.next = not fbus1.full
src_rdy_o.next = not fbus3.empty
# @todo: fix the m_fifo_async bug!!!
# hackery, need to fix the simultaneous write and read issue
# with the async FIFO!
@always_seq(rclk.posedge, reset=reset)
def rtl_ed1():
if ed1:
ed1.next = fbus2.empty
else:
ed1.next = True
# the original was a chain:
# m_fifo_fast (16)
# m_fifo_async (64)tx, (512)rx
# m_fifo_fast (16)
# the two small FIFOs were used to simplify the interface to
# the async FIFO, the async FIFOs have some odd behaviors, the
# up front fast fifo wasn't really needed.
# the small fast FIFOs have a simpler (reactive) interface
# it works more like a register with enable(s).
gfifo1 = m_fifo_fast(wclk, reset, fbus1)
gfifo2 = m_fifo_async(reset, wclk, rclk, fbus2)
gfifo3 = m_fifo_fast(rclk, reset, fbus3)
return rtl_assign1, rtl_assign2, rtl_ed1, gfifo1, gfifo2, gfifo3