two_clocks.py

from myhdl import *
from multiprocessing import Process, current_process, Value, Event, Semaphore

process_count = Value('i', 0)
sync_semaphore = Semaphore()
all_synced = Event()

def synchronise():
    with sync_semaphore:
        process_count.value += 1
        if process_count.value == 2:
            process_count.value = 0
            all_synced.set()

    all_synced.wait()

def metaclock():

    @instance
    def metaclock_driver():
        while True:
            yield delay(1)
            synchronise()


    return metaclock_driver

def clock_driver(clock, period):

    first_delay = period//2

    @instance
    def clk_driver_inst():
        while True:
            clock.next = not clock
            yield delay(first_delay)
            clock.next = not clock
            yield delay(period - first_delay)

    return clk_driver_inst


def simple_counter(clock, reset):

    counter_state = modbv(0, min=0, max=20)
    @always_seq(clock.posedge, reset=reset)
    def counter():
        print('process %d, counter %d' % 
              (current_process().pid, counter_state))

        counter_state[:] = counter_state + 1

    return counter


reset1 = ResetSignal(0, active=True, async=False)
reset2 = ResetSignal(0, active=True, async=False)

clock1 = Signal(bool(0))
clock2 = Signal(bool(0))

sim1 = Simulation(
    [clock_driver(clock1, 9), simple_counter(clock1, reset1), metaclock()])
sim2 = Simulation(
    [clock_driver(clock2, 3), simple_counter(clock2, reset2), metaclock()])

process1 = Process(target=sim1.run, args=(50,))
process2 = Process(target=sim2.run, args=(50,))

process1.start()
process2.start()

process1.join()
process2.join()