Readserial() 
  While true:
    Read the serial port (I know how to do this) 

    If readbyte = 0x65: #(for example) 
       Kill or start function1() #(but at the same time Readserial() should continue monitoring serial port) 

    If read byte = 0xFF: #example
       Kill or start function2() #(again readSerial() should continue to run) 

Function1() 
  Do something

Function2()
  Do something 

(Mar-03-2018, 09:08 PM)Larz60+ Wrote: what is the device that you are using, raspberry pi, arduino? I'm thinking there must be a way to trigger an interrupt (event in python) when there is a charater in the UART buffer. Tell me device you are using, and type of serial (i2c, usart, spi, etc.) Once I know this, I can look at your available options.

(Mar-03-2018, 09:33 PM)marsokod Wrote: You may want to use a thread or a process depending on what your function1 and function2 are doing. You can either start them manually, use a library like APScheduler to have a pool of threads/process and add your function to the job queue, or start thread/processes at the beginning of your code and have them read elements in a queue. In the last case, your ReadSerial function would only have to put an element in a queue, which should minimize any interruption to the monitoring.

(Mar-03-2018, 10:16 PM)ricardons Wrote: Function1() acquires sensor data and show it on lcd
Function2() is the same as 1 but also writes the data to a text file

So threading?

(Mar-03-2018, 11:08 PM)marsokod Wrote:

(Mar-03-2018, 10:16 PM)ricardons Wrote: Function1() acquires sensor data and show it on lcd Function2() is the same as 1 but also writes the data to a text file So threading?

Yes, threading since you will be mostly IO-bound so there is very little risk of suffering from global interpreter lock. Unless Larz60+ has a better solution, I would advise going with the third option I gave you: At the beginning of your code, create 2 queue.Queue() and start 2 threads fetching data from these queues with a timeout. This timeout shall be big enough not to impact your performances with too many loops, but small enough as it will be the time you may have to wait to shut down your program. I run CAN bus monitoring on a Raspberry Pi and had no problem with a loop of 10ms, but 100ms should be even safer. Your serial monitor will just put a meaningful value in the corresponding queue. Your threads will pick this value up and act accordingly. When the main program shuts down, you can put a None value in the queues and make sure that your threads interpret that as a signal they should leave the queue monitoring loop and return. This way, your threads close nicely.

(Mar-03-2018, 09:33 PM)marsokod Wrote: You may want to use a thread or a process depending on what your function1 and function2 are doing. You can either start them manually, use a library like APScheduler to have a pool of threads/process and add your function to the job queue, or start thread/processes at the beginning of your code and have them read elements in a queue. In the last case, your ReadSerial function would only have to put an element in a queue, which should minimize any interruption to the monitoring.