deadlock.py

from myhdl import Signal, block, always_seq, instance, delay


@block
def deadlock():  # not convertible
    sig1 = Signal(bool(0))
    
    @instance
    def initialpush():
        yield delay(10)
        sig1.next = True
        
    @always_seq(sig1.posedge, reset=None)
    def posdriver():
        sig1.next = not sig1
        
    @always_seq(sig1.negedge, reset=None)
    def negdriver():
        sig1.next = not sig1
        
    return initialpush, posdriver, negdriver

dlinst = deadlock()
dlinst.config_sim(trace=True)
dlinst.run_sim(duration=100)
 
   
@block
def deadlock2():  # can be convertible
    sig1 = Signal(bool(0))
    sig2 = Signal(bool(0))
    sig3 = Signal(bool(0))
    
    @instance
    def initialpush():
        while True:
            yield delay(10)
            sig1.next = True
        
    @always_seq(sig1.posedge, reset=None)
    def posdriver():
        sig1.next = not sig1
        sig2.next = sig1
        
    @always_seq(sig1.negedge, reset=None)
    def negdriver():
        sig3.next = sig1
        
    return initialpush, posdriver, negdriver

dlinst2 = deadlock2()
dlinst2.config_sim(trace=True)
dlinst2.run_sim(duration=100)