What are you doing with RISC OS?

by polling a pin in a repeat…until loop and incrementing a counter.
Most people run from software timing loops as the actual time it takes is highly dependent upon what the machine is actually doing, what sort of machine it is, core processor speed, code paths through the program, blah blah blah. It might only be nanoseconds, but just like a shopping bill, all the little bits add up.

I anticipate that each reading will take 0.1 to 0.2 seconds which is why the centisecond timer cannot be used.

Sure it could. Just because it ticks away at 100 ticks per second doesn’t mean you need to do something every tick. If the readings take 0.1 to 0.2 seconds each, well, the first thing is to measure that. Then you can work out to take a reading, say, every 20cs (0.2s) or maybe every 25 (0.25s). This will give your readings a consistency, it’ll be a regular five per second or four per second. Whatever turns out to be the appropriate interval.
Then, at least, you have a solid known amount of time that has elapsed between readings.

so there is some scope for taking several readings and averaging if the threshold voltage differs slightly each time.

Indeed. Don’t do a Boeing and rely upon one reading from one sensor. ;-)

Given domestic equipment, it is quite likely the readings may differ slightly. You’ll need to see how much is an acceptable margin. It’s a balancing game between “these are the same basic value” and not missing something when the value changes.

I did get a data monitor reading eight GPIO inputs at 1500Hz, just using null polls from Wimp_Poll and BASIC, until one of the pins changed state at which point I did a ‘debounce’ (as it was monitoring pairs of relay contacts) by taking a voltage sample, which took 1cs. I found that a write to the SD card (which would happen once there was enough data to require a write) could consume 5cs. This picked up the sequence of state changes nicely.

I can tell you what I’m not doing with RISC OS – getting anything done.

I’ve got a couple of minor changes to some my old RISC OS programs on the go, the sort of thing that used to take a me couple of hours at the most, but I’m finding it enormously frustrating to make any progress in the limited time available. There are all the issues there have always been; the paper thin fragility of RISC OS meaning constant reboots (not just of the target machine, but Zap falling over or the USB stack hanging on the development machine), the lack of any proper debugger meaning falling back to old ways of trying to instrument executables, the lack of frameworks and libraries to make the job easier.

But the main problem is I’ve fallen out of love with the RISC OS API, I’ve forgotten enormous amounts, and on relearning things, it seems so low level and not joined up – the amount of glue code to do the simplest thing is excessive, and wheels have to be constantly reinvented. I pride myself I can switch from real-time embedded in raw C code on F1 ECUs to video conferencing control code in Python with the aid lots pre-written libraries, and have done most things in between. But with RISC OS you have to attempt to achieve high level functionality with low level APIs and tools, there just aren’t the building blocks you can use to get from the idea to the solution without getting mired in glue and guess work debugging, it’s just not fun for me any more.

I find it hard to disagree with that!

It’s amazing how much just isn’t there in terms of frameworks/libraries, and how everyone seems to have to re-invent their own wheels. Even when I browse bits of the RISC OS source code, I’m seeing the same functions again and again.

I know, I know… it’s all from the days when you had 4MB RAM, so thins were different. But things have moved on!

But things have moved on!

Huge swathes of assembler. Bits of code called “Arthur2” and…

🎵 Let’s do the Time Warp again

(it’s just a jump to the left…)

it’s just a jump to the left…

I thought jump¹ was an x86 thing.

¹ Just a low level GOTO with less clarity.

it’s just a jump to the left…

And then a step to the right.

Now we’re into BASIC territory. ;)

But where does shake it all about come in?

Nowhere, without pelvic thrusts

For anybody who isn’t getting the references, I’ll just leave this here…

https://www.youtube.com/watch?v=umj0gu5nEGs

(it’s Friday night, do you need an excuse to enjoy some awesome? some very weird awesome?)

Nice! Good video for first thing on a Saturday morning!

Heh heh heh.

I’m sure I know the actor at 2:35 from something like Swap Shop. (It was filmed in England with local actors.)

Never mind, it was Christopher Biggins https://en.wikipedia.org/wiki/Christopher_Biggins

That’s my first time using RISC OS. So currently I’m excited learning about it and will try some coding on it later on :)

What are you running it on? What sort of thing are you hoping to code?

That’s my first time using RISC OS.

Welcome to RISC OS and the forums!

Hi Michael, thank you!

Hi Dave, I’m running it on a Raspberry Pi 4. I’m not sure what to code yet – will need to get used with the system first – I’m a dev but not familiar to Assembly lang, so I want to learn it a bit and try some BASIC as well and learn more about the ARM set.

@ fapuro

Welcome!

I’m not sure what to code yet – will need to get used with the system first

We are building a Youtube channel to help folks which want to have fun coding on RISC OS and need to get familiar with the development on it.

You can find it here:

https://www.youtube.com/channel/UCr4zW_z3WfBVBha3droh_rQ

There are already 20 videos and more will come soon, hope this will be useful to you, cheers!

hi @Paolo, ohh yes! I saw your videos playing code with the CapsLock earlier and tried them as well. Thanks a lot! those videos are pretty helpful! I’m waiting my DDE to arrive too and will definitely follow to learn more :)

Thanks a lot! those videos are pretty helpful!

My (although I should say OUR) pleasure. All the people helping deserve a lot of credit: Sprow, Gerph, Cameron and Matt as well as all the folks on YouTube, Twitter, Discord, Stardot and via email who gave use suggestions and reviews.

I’m waiting my DDE to arrive too and will definitely follow to learn more :)

Nice! All the best with your journey and have fun! :)

As a very new user who couldn’t really use RISC OS properly until it developed wifi support, I’m looking around, seeing what it can do. I like the fact it is very different from every other OS