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Forum Index : Microcontroller and PC projects : A different take (maybe not) on switch debounce..
| Author | Message | ||||
| Tinine Guru  Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
I don't care for "PAUSE" because I like to keep SETTICK alive. Do for i% = 1 to 500 'Needs 500 consecutive samples of high, to be valid if not pin(GP14) then i% = 1 next select case tempset% case 0 tempset% = 1 case 1 tempset% = 2 case 2 tempset% = 4 case 4 tempset% = 0 end select port(GP11,3)=tempset% for i% = 1 to 2000 'Needs 2000 consecutive samples of low, to be valid if pin(GP14) then i% = 1 next Loop until inkey$<>"" |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5091 |
This keyscan completely saturates the CPU. If that is your plan that is okay (when you have nothing to do otherwise, but spend time in an "idle" DO:LOOP). That means that all processing has to take place in the SETTICK. I know sometimes solutions like that are needed, but I prefer to see SETTICK as an interrupt, and would spend little time there. And much time at main level. By the way: SETTICK is not affected by PAUSE. It simply continues through the PAUSE (picomiteVGA 5.07.05b6) Edited 2022-06-09 06:10 by Volhout PicomiteVGA PETSCII ROBOTS |
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CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
Jack Gansell did a lot of research on the best algorithms with really good supplemental evidence. I took one of his examples which keeps a rolling sample allowing your program to get on with it's stuff but still know the state of a switch when you need it. I use it a lot, I even added it to Volhout's component tester software when I replaced the touch buttons with real ones. find my MMBasic code here Edited 2022-06-09 06:33 by CaptainBoing |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
I totally agree! And to paraphrase Charles Petzold (Programming Windows); "the best way to use interrupts is not to"  and I concur, which is why I am a devout Propeller user...we don't need the darned things.However, in process control, you often need some form of determinism and this is where SETTICK comes in. I don't subscribe to the "just set a flag and get out". Moreso using ByPic, my entire process runs in the ISR. Good to know that PAUSE is non-blocking  Craig |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
Same as I just demonstrated, no? Craig |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
I think we are saying the same thing. Gansell's take was to utilize the loop of Main to do the work and ignore the state, accumulating the sample into a count regardless of whether you care at that time, so no dedicated handler with all its foibles. Gansell's code just runs a single line of code (per switch) on the main loop. Each time through Main, does the shift then you get on with everything else, regardless of any changes in the state of the switch. btn=btn<<1 Xor Pin(Switch) And &h1f That line of code runs like a jack-rabbit even on the lowly '170 and you can use a few tricks to speed it up even further, like using CONSTs for the fixed values, or dropping the final AND, only doing it when you test the variable (although if you do that each time through Main what is the point?). <1.4mS at 5MHz, 159uS at 48 (blimey!). Whenever you need to check the switch, you just look at variable btn. In the case above with active Lo you are only interested in 0, anything else is either not pressed or bouncing. All the work was done "in the background" by that line of code in the main loop. jus' sayin' Edited 2022-06-09 15:36 by CaptainBoing |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
Oh, absolutely! I wouldn't actually implement as shown (just test code). I never write anything that could potentially freeze the system. When checking machine inputs, for example, I always establish a reasonable timeout, after which, I put the machine in a safe condition and throw-up a timeout message. Otherwise, someone might approach a stopped machine and it could potentially take-off running again...not good  Actually, this is a scary aspect of programming being accessible to all. One might be a wizard at coding but not understanding the process and safety pitfalls is darned dangerous Craig |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
sorry Craig, we keep crossing in the mail what you doing up at half six, I thought I was the only one sad enough to be doing this stuff with the birdssee my updated post Edited 2022-06-09 15:38 by CaptainBoing |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
I can see this turning into a Monty Python sketch Sad? You don't know the meaning of the word....I'm under the gun and so I have a sleeping-bag in this factory...never take a day off. Not even Xmas. TWO ex-wives can tell you all about it .You ever walk away from your work with a niggling issue and you either grab a pint or hit the sack and the solution hits you? And now you can't wait to get back to the project? Drives me nuts Craig |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
I don't have the exes (still on wife No.1... I don't think I am gonna make it ), but yes I completely identify with that situation. ordering dominoes at 11pm is not funny.In my life I have had, I think, three occasions where I have dreamt the solution to a problem. Not so much now-a-days but when I was a much younger man I used to keep a notepad by the bed. Working out how to get addressable pixel graphics on a text only display using a TI controller... TMS9918 or something like that was a particularly memorable one. Good luck with your project |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
I think that dogs and cats have it figured out. They take frequent naps and have energy when they need it. We, however are accustomed to making the most of available natural light and so we slog it out. I do the nap-thing at weekends because I have the factory to myself and my weekend productivity is through-the-roof compared to Mon-Fri. It helps that I live/sleep/breathe machine control and that I can't abide TV or nothingness conversations...Just wish Thebackshed was my local pub Craig |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
agree on that. When I was a programmer full-time, there was always something cathartic about 3am that made writing code so easy I haven't had a TV licence for two years - finally convinced wife it was all sh*te and just rots yer brain. haven't looked back. the various subscription services give much higher quality content and you can choose what/when/how much to watch. I really can't abide stuff like BGT and strictly etc. just the lowest of the low and I ain't paying for it! |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
I'm close enough to your local pub to take the Backshed there for you. :) ====================== Cap'n: I wish I could convince 'er indoors of the same... She loves cookery & sewing & crafts and will watch anything associated with them. I've had to learn how to switch off. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3378 |
Haven't had TV/cable for 15 years (but may still spend an inordinate amount of time on Amazon, Netflix, youtube, not to mention doom-scrolling). But re "She loves cookery & sewing & crafts and will watch anything", me wyfe finds plenty of that streaming. Since high school I've awakened with solutions to daytime problems percolating up. Nap every afternoon, and have done when possible for 50 years. Even on every sunny day after lunch on a mat in a park across the street from where I was working. But I'm glad it's been nearly 5 decades since I last used a sleeping bag at a workplace. Agree about the productivity of weekend times, and for me, especially the week between xmas & new year's when no one else was around. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
My wife is the same. there is tons and tons of really interesting stuff on YT. get yer missus into that then turn all the broadcast stuff off - its like a breath of fresh air not having the 20 minute loop tape of "news" running and all the garbage cheap telly. Then you can regale each other with what you found on "Pasta Grannies" Edited 2022-06-09 22:29 by CaptainBoing |
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| Tinine Guru Joined: 30/03/2016 Location: United KingdomPosts: 1646 |
Cap'n, you're suspect...you dropped the TV tax after Jeremy Kyle got shut down, right? Craig |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2170 |
that's daytime TV... who has time or few enough brain cells for DTTV? garbage. Atch' that's unfair... most TV is garbage. It got to the point I'd be watching 20 year old repeats of star trek as the only thing vaguely entertaining... paying sky for he privilege and paying a TV licence. cancelled them both on the same day  Lizby is on the money. I am a late starter. to think of the hours I wasted. Edited 2022-06-09 23:33 by CaptainBoing |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3378 |
When we travel and turn on the TV in a motel, all the ads are staggering. It's a great reminder of what we're missing (and not missing). PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7938 |
Those 24hr soddin' craft advertising channels are truly horrible. :( Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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