Simple Threading and Serial User Interface library for the Arduino

RE: Simple Threading and Serial User Interface library for the Arduino

e14 Contributor — Wed, 20 Aug 2014 12:54:03 GMT

Dear Members as I read your blogs I am daily thankful and amazed.

What a gift to be able to create, make, fix.

Thankyou to all,

Laureen

RE: Simple Threading and Serial User Interface library for the Arduino

Robert Peter Oakes — Wed, 14 May 2014 15:57:36 GMT

you put the scanning of the IO (Analog or Digital) into the interrupt routine and have it coded very efficiently so no maths or other interpretation of the results, just raw input

then the main routine that can be interrupted without affect can simply monitor the variables managed by the IO interrupt to make decisions and perform maths functions to its hearts content

A semaphore system could be used to notify the routines when critical calculations are under-way to inhibit the interrupt from changing values part way through use. Or use a double buffer where the interrupt updates only one buffer and the main routine disables interrupts only long enough to copy the buffer. This would eliminate the race hazard altogether

RE: Simple Threading and Serial User Interface library for the Arduino

Workshopshed — Wed, 14 May 2014 12:11:21 GMT

Hi Garrett,

I do have a project where it has multiple tasks to do, read RTC, move steppers, respond to serial input. However, I was planning to approach the problem by ensuring that none of the actions were blocking (or at least not for any significant duration). I don't have any long calculations so I'm not sure that these threading libraries will help.

For your monitor approach I'd be tempted to use a timer interupt to handle the setting of the output values as that is the critical item. For the alarm you could store the time value when you start the alarm and then periodically check to see if the right period has elapsed to turn it back off again, that does not need to be a blocking operation. I'd make sure that the LCD was an I2C one to avoid having to do too much processing on the microcontroller.

Arduino 101: Timers and Interrupts | Let's Make Robots!

For your long calculation how do you ensure that the calculation does not block? It would seem all the examples use PT_WAIT_MS to have co-operative multi-tasking so do you split your calculations into steps and call PT_WAIT_MS inbetween?

RE: Simple Threading and Serial User Interface library for the Arduino

e14 Contributor — Wed, 16 Apr 2014 19:28:18 GMT

Post has been updated to reflect the most recent revision. Functions and Variables now take up 0 bytes of SRAM, and threads only take up 4!