Interrupt function in python

Question

I'm using modbus protocol to communicate with my program. When slave gets signal from master on register 1 he starts function

def main():

    #Create the server
    server = modbus_rtu.RtuServer(serial.Serial(PORT))
    server.start()

    slave_1 = server.add_slave(1)
    slave_1.add_block('0', cst.HOLDING_REGISTERS, 0, 2)
    slave_1.set_values('0', 0, 0)         #set value on the begining
    slave_1.set_values('0', 1, 0)         #set value on the begining

    while True:

        register_1 = slave_1.get_values('0', 0, 1)
        register_2 = slave_1.get_values('0', 1, 1)


        if register_1[0] == 1:

            time.sleep(3)
            slave_1.set_values('0', 0, 1)
            time.sleep(3)
            slave_1.set_values('0', 0, 0)

I want stop this function when I change state on register 2 for few seconds, after this time it should come back to place when it was stopped. It should be immediately, so I can not check this is normal "if". It should by similar like interrupt in arduino.

Question: How can I create this interrupt?

Answer 1

Unfortunatelly I don't know any similar python function like interrupt in arduino.

If you want to stop this program use:

    if register_1[0] == 1:

        for i in range(300): #for 300ms
            if register_2[0] == 1:
                __STOP_PROGRAM__
            time.sleep(0.1) #sleep 1ms
        slave_1.set_values('0', 0, 1)
        for i in range(300): #for 300ms
            if register_2[0] == 1:
                __STOP_PROGRAM__
            time.sleep(0.1) #sleep 1ms
        slave_1.set_values('0', 0, 0)

It's not immediate, but if you need more exact, you can increase a value in range() and decrease a value in time.sleep()