TheBackShed.com

Forum Index : Microcontroller and PC projects : Suggest real time micro dev board?

Page 2 of 2

Author

Message

panky

Guru

Joined: 02/10/2012
Location: Australia
Posts: 1099

Posted: 12:53pm 16 Feb 2016

Copy link to clipboard

Print this post

Hi Lou,

Sounds like a major undertaking on your part. A couple more questions please which may help board members offering advice?

Are you proficient in any language (C/C++/python etc.)?

Can you give us an idea of your hardware/electronics knowlege/expertise?

Answers to these two questions will determine to a large degree the time from concept to working system.

A powerfull, costly elegant hardware system using an advanced language like C++ would do everything you want but the time to master would be considerable and costly if you are not proficient in both hardware and software.

Not knowing your proficiency, might Geoff's Micromite+ and an Explore64 board be a good and cheap way to get your feet wet and determine where to advance to as the project develops? see www.geoffg.net/micromite.html

Doug

... almost all of the Maximites, the MicromMites, the MM Extremes, the ArmMites, the PicoMite and loving it!

louarnold
Newbie

Joined: 12/02/2016
Location: Canada
Posts: 11

Posted: 04:14pm 16 Feb 2016

Copy link to clipboard

Print this post

To JohnS:

JohnS said H/w will do most things. Some old, crude, chips don't have USB or you bitbang it - I'd avoid such. UBS3.0 is only on some chips as yet so avoid unless it's vital.

I agree.

JohnS said Many chips are NOT 5v-tolerant. If it matters so much, be wary (check errata not just datasheets!) or look at level converters.

I understand, and have come across this before with the RPi.

JohnS said I'm unsure what your s/w will do other than wait for h/w so can't guess whether 80MHz is far faster or slower than you may need. However, do bear in mind people on here appear to be doing roughly the things you want and working fine with an interpreted Basic (essentially because the h/w does so much and 40Mhz etc is most of the time fast enough for the rest). I'm not suggesting you should use Basic but compiled C is say 20x faster so I do wonder why you feel the need for vast speed?

I programmed in assembly language for years and prefer that for the real-time critical code. C is fine for non-critical code. Interpretive languages cause too many headaches in response time.

JohnS said I expect you don't need expensive dev boards. ST make very low cost boards (but check the licence suits you - probably fine for dev use then get something off ebay/etc that's not made by ST) or you can get good cheap PIC32 ones anywhere except Microchip (I can't swear they have NONE but you get the idea).

More powerful boards exist so it's back to what you want and is it available without proprietary stuff.

Thanks for the license heads up. And cost is always on my mind.

JohnS said For more ideas if there's an RTOS you like have a look at the chips it supports and then look for boards with those on.

Yes, that's a good idea. Whatever an RTOS works on becomes a candidate platform.

JohnS said By way of example, a PIC32 may have say 512K flash so no need for SD card unless you want to write data to it. An ST (STM32) may well have 1MB or more flash. Etc. If you're going to write that much in C/C++ you'll be busy for a while.

Again, I will write in assembly language and C. And, yes, the assembly language curve for the chosen processor will be rather steep. Its a consideration. But again, the non-real-time code will be in C. It will be small because processing is off-loaded, and its likely that much has already been written and simply needs to be adapted.

JohnS said BTW, OpenOCD supports more than JTAG (SWD, ICSP, etc).John

Ahhhh, I was worried about just that topic. Thanks for the heads up.

With Thanks,
Lou.

louarnold
Newbie

Joined: 12/02/2016
Location: Canada
Posts: 11

Posted: 04:38pm 16 Feb 2016

Copy link to clipboard

Print this post

To Doug:

The undertaking itself is highly instructive, to me and I hope to others. <grin> Its a bit easier than the math for quantum physics, so that helps.

Languages: I answered in the response to JohnS. Summary: Assembly language is preferred, C is good, all others are not suitable.

Hardware: I took a college course that required both analog and digital hardware used with a PIC 16 controller. I missed the A+ because I burned up too many temperature sensor chips. Analog stuff will always be a black art to me.

Micromite+ and an Explore64 board: What is the Explore64 board... just a board for 'mite? Is this term correct: Explore64 vs Explorer 64.

As I stated early in the thread, I can run my grandfather's scooter fwd/rev with the Arduino and a 5v/24v converters.

Regards,
Lou.

Edited by louarnold 2016-02-18

isochronic
Guru

Joined: 21/01/2012
Location: Australia
Posts: 689

Posted: 09:28pm 16 Feb 2016

Copy link to clipboard

Print this post

A UBW32 might be good, a bit long in the tooth now but that means it
has some user momentum , software examples and heritage, MPLABX,
has had bugs fixed, and so on .
That would allow some easy MIPS assembly as well.
A recent '795 pcb effort is "NU32" (web) although I found the site(s)
a bit muddy.
The pic32mx795 is fairly common in other boards and platforms, it would be a good
initial point prior to '470 or the mz A2's which are said to be imminent
(? - any news ?).

(ed) - I think the USB capability of some ics is not crucial anymore, unless
your new product will be based on it. Wireless is making it obsolete
for many applications.

- The dspic33e ic's might be worth a look, 64k ram / 256k flash / 12 bit ADC
in basic dip versions isn't bad.Edited by chronic 2016-02-18

JohnS
Guru

Joined: 18/11/2011
Location: United Kingdom
Posts: 3678

Posted: 09:27am 17 Feb 2016

Copy link to clipboard

Print this post

For some ideas of PIC32 boards: http://retrobsd.org/wiki/doku.php/board/index

For STM32 ones, see mouser/farnell(element14)/RS.

A cheap source of PIC32 boards http://www.bypic.byvac.com/index.php/BV502_V2

Much more powerful but only about $16 LinkIt Smart 7688 32MB flash 128MB RAM 580MHz
(not sure if any proprietary blobs)

Using assembler for any modern CPU with the sort of features you mention would be ... er, odd? bizarre? painful? Certainly ruins portability.

JohnEdited by JohnS 2016-02-18

Page 2 of 2

Print this page

To reply to this topic, you need to log in.