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#52421 Embarassing SPI question (re: Netduino Helper Max72197221.cs )

Posted by hanzibal on 28 August 2013 - 06:30 PM in General Discussion

The thing to look for is probably that LOAD doesn't go high in between bytes but only in between 16 bit words otherwise the chips might get confused. I'm not sure, but I don't think the ushort array SPI methods actually use 16 bit word length so trying explocit variable word length SPI is definately worth a try. A thing to try next where you are more in control of the signals, would be to bitbang the thing, i.e using gpio for CLK, DIN and LOAD/!CS. That way you could check to see if the chip really works the way you think it would. If it does, it's probably an SPI thing.



#52474 Embarassing SPI question (re: Netduino Helper Max72197221.cs )

Posted by hanzibal on 30 August 2013 - 02:12 PM in General Discussion

;)

I think variable SPI word length also would have solved the problem - did you try it using 16 bit words?




#52610 Embarassing SPI question (re: Netduino Helper Max72197221.cs )

Posted by hanzibal on 06 September 2013 - 10:31 AM in General Discussion

Yes so it seems.

 

...however, when come to think of it again, I'm not sure h/w SPI is supposed to raise !CS until the bit stream has been sent in full (e.g. !CS keps low in between individual bytes) but according to this image it does briefly:

Posted Image

 

Whereas in this picture it does not:

Posted Image

 

I'll have to look in my scope to see exactly how SPI behaves (or misbehaves) on the Netduino.

 

Interesting info about the emulator, I was unaware of there being such a thing with hardware models. Is it part of Visual Studio or do you have to download it explicitly - if so from where?

 

Is the [color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]MAX7219 mimic part of the emulator or did you write and add that yourself?[/color]




#49457 Issues with buttons and LCD

Posted by hanzibal on 15 May 2013 - 05:20 AM in Netduino 2 (and Netduino 1)

I agree, it's hardly a h/w error "anymore". Using a shiftregister would probably help but you need to change your wiring to use SPI with the shift register and probably have to use a different library (e.g. Mario's) too. Before trying that, I could post you some code to try when I'm home after work today. That code would be more or less a drop in replacement.



#52472 Embarassing SPI question (re: Netduino Helper Max72197221.cs )

Posted by hanzibal on 30 August 2013 - 01:52 PM in General Discussion

Good you found it and that's exactly what I meant when I wrote this:

 

The thing to look for is probably that LOAD doesn't go high in between bytes but only in between 16 bit words otherwise the chips might get confused. I'm not sure, but I don't think the ushort array SPI methods actually use 16 bit word length...




#49505 Issues with buttons and LCD

Posted by hanzibal on 17 May 2013 - 06:59 AM in Netduino 2 (and Netduino 1)

I know that appearance only too well, I'm now quite positive it's a timing issue. Before employing an alternate board, you can try tweaking the code a bit. If you dive into the driver source, there's a method called _WriteNibble that basically does all data transfers to the LCD. As you will see, there are two lines of code driving the E pin. For starters you could try increasing the delay before lowering the pin to 2ms instead of just 1ms. The delay shouldn't be necessary since minimum data setup time is just 80ns but in comparison to which, even 1ms is an eternity but still worth a try. If that does not help, you can try other means but I'm on a train now and haven't got access to the code.

 

EDIT: When looking more closely to your setup, I noticed that your pull-downs on d0...d3 are wrong - I meant to pull down each of them separately. At this point, you can simply remove the pull-downs all together.

pulldowns.jpg




#49508 Issues with buttons and LCD

Posted by hanzibal on 17 May 2013 - 01:43 PM in Netduino 2 (and Netduino 1)

Not really, it's just because they're not needed anymore and the fact that you have bridged them which might not be 100% healthy.

 

I feel very confident it's a timing issue. When thinking about it, the fact that you do see characters suggests that the LCD controller is actually correctly configured for 4 bit 16 x 2 mode and hence responds to commands. So why does data get garbled?

 

This in turn suggests the problem has to do with the RS pin rather than the E pin....Have a look at fig. 25 on page 58 and then page 52 in the d/s describing the timing characterstics:

https://www.sparkfun...LCD/HD44780.pdf

 

The driver works on my mini but then again, the NP2 is much faster which could affect timing. Anyway, before going down that lane, I think you should try the E pin code mod I suggest earlier. If that doesn't help, you could try moving the E pin assertion to just before the data pins are written to.

 

I believe you're almost there now!




#49530 Issues with buttons and LCD

Posted by hanzibal on 18 May 2013 - 01:33 PM in Netduino 2 (and Netduino 1)

That's great news!

Not to be a kill joy, but the necessity of such a long delay is likely only a symptom of the actual problem likely being something else. l should think it has to do with the RS pin and it should be further investigated. I might look into it when I find the time.

In my PCF8574 based driver, the delay is only 100us and that works perfectly well.

If you decide to make a PCB for your project, may I suggest you use the pcf8574 io expander. It's I2C and should save you some 4 pins of which you could use one for controlling brightness via PWM, periodically sampling a photo resistor to automatically adapt to variations in ambient light (daylight compensation). The code is available in this post:

http://forums.netdui...-and-ir-remote/



#55286 Embarassing SPI question (re: Netduino Helper Max72197221.cs )

Posted by hanzibal on 10 January 2014 - 08:41 PM in General Discussion

Make sure you got a class called "Program" implementing a static method void Main() - that method is your application entry point and will be called when the run time environment is ready to launch your application.




#56332 My daydream - FPGA/ARM platform

Posted by hanzibal on 24 February 2014 - 09:17 AM in General Discussion

How much of the io is available on that kit?, and.. is this an dip?

If you mean the PSoC 1 eval kit that I got, all pins are broken out on headers and and there's a small proto aside of them too plus an LCD header with a 16x2 LCD included (LCD driver is one of those module that you drop which becomes h/w after programming the chip).

 

The kit comes with a couple of DIP28 sample ICs. I purchased the smaller DIP8 version separately and programmed it while sitting in the breadboard, e.g. didn't use the eval board with that one even though it is of course possible (you need to put a couple of jumper wires since the ISSP pins are differently located physically).

 
In the end my little chip got this pin out - flash protection, a few goes with the sander, write a datasheet and then roll it out to market  ;)
pinout.PNG

 

 

Haven't seen that one - love the form factor and pretty inexpensive too, in other words - it looks just like my average "must have"  :ph34r:




#56335 My daydream - FPGA/ARM platform

Posted by hanzibal on 24 February 2014 - 09:34 AM in General Discussion

Oh and btw, the thing I wrote about sanding off the chip is no joke, there are vendors doing exactly that!



#56334 My daydream - FPGA/ARM platform

Posted by hanzibal on 24 February 2014 - 09:25 AM in General Discussion

No, sorry for being unclear - I purchased a blank cy8c27143 device in a DIP8 package and then programmed my own firmware onto that. Voila!



#56327 My daydream - FPGA/ARM platform

Posted by hanzibal on 24 February 2014 - 06:55 AM in General Discussion

Don't let me tempt and lead you a stray now, keep your eyes on the road and your hands on the wheel there chief! Ha, ha - I got a special folder on my desktop saying "cool stuff" and a similar one in my email plus tons of little things in anti static bags (many of which are still unopened). I'd say I got gizmos, chips and kits to span a few life times of tinkering but I don't mind, most of the stuff was really cheap and dreaming of what to do with them is free :-)



#56322 My daydream - FPGA/ARM platform

Posted by hanzibal on 24 February 2014 - 12:30 AM in General Discussion

After this I actually started working on something vaguely similar to my "day dream" but then (as I predicted), put it on hold for an undefined amount of time in favor of other more urgent or interesting projects. I got as far as a simplistic simulator of digital electronics with a built-in on-line repository and the idea (dream) was to somehow being able to render the "hardware models" on an actual cpld or fpga board. Recently however, I spent some time playing around with a PSoC 1 eval kit from Cypress that I had laying around unused for a year. Naturally, it turned out the guys at Cypress had already accomplished more or less what I was thinking of maybe doing - and it has been around for quite some time too! Basically, the PSoC designer software (graphical IDE) lets you drag-drop blocks implementing stuff like op amps, filters, PGAs, comparators, timers, PWMs, DACs, ADCs, etc onto a canvas using a GUI. You interconnect data lines of a matrix using muxes and you can have the integrated 24Mhz micro controller interact with your blocks. I found it all totally awsome and ended up having implemented a stereo headphone amplifier with built-in NEC IR decoder (volume, balance and a few other features) with surpricingly good sound quality in a single DIP-8 package - my very first ASIC for crying out loud :-) image.jpg So, if you need a specialized chip to help your Netduino in performing some sub task, you can use PSoC to create a device that does the job and then just snap it down your breadboard alongside your Netduino. Such sub tasks could be small but timing critial work or some special analogue processing. You'd then transfer the results to your Netduino and have it readily available for conveniant processing in .NET C# (or VB) - the latter of which PSoC does not offer. PSoC can act as Netduino's little helper!



#50502 My daydream - FPGA/ARM platform

Posted by hanzibal on 15 June 2013 - 08:22 PM in General Discussion

Hey neslekkim, did you get a PSoC and have you tried it yet?



#49634 My daydream - FPGA/ARM platform

Posted by hanzibal on 21 May 2013 - 07:25 AM in General Discussion

cutlass, you obviously know tons about this stuff and I'd love to discuss it further.

 

I find this tech very exciting and I have to look into the info you supplied.




#49626 My daydream - FPGA/ARM platform

Posted by hanzibal on 21 May 2013 - 02:28 AM in General Discussion

Sort of, I was thinking of something like that but more in a general sense than a specific device or vendor. I recently ordered a Cypress PSoC 4 demo board and a PSoC 1 dev kit to explore that magic tech:
http://www.cypress.c...9&source=header




#49611 My daydream - FPGA/ARM platform

Posted by hanzibal on 20 May 2013 - 09:38 PM in General Discussion

Here's my daydream for a development platform
 

Think of how  programmable logic like FPGA and CPLD devices work and how they let you implement pretty much any hardware in a single device, basically an ASIC. Imagine different hardware modules available from a palette of  ready made drop-in software modules through some easy to use (semi-)graphical IDE. Also imagine using C# (or VB.NET) as the glue between the modules to orchestrate them - instead of VHDL (!!)

 

A development platform like that would virtually let you implement your whole breadboard in a single device!

 

There would be much less need for external parts like shift registers, 74LSxxx (and, or, xor, etc), transistors, IO-expanders, LCD backpacks or even motor drivers and audio devices...well almost anyway, you'd still have to add a LED or a switch here and there  :lol: 

 

Open Source Hardware would get a truly profound meaning. We could be writing and sharing OSH modules in an on-line in-project repository, simply download what you need and drop it into your project. We'd be talking breadboard virtualization and the ability to jump between any old breadboarded project simply by uploading a piece of firmware to the device. To me, this too would be a time machine!

 

Would you like a platform like that or is it just me?   :)




#49659 My daydream - FPGA/ARM platform

Posted by hanzibal on 21 May 2013 - 12:17 PM in General Discussion

[color=rgb(40,40,40);font-family:helvetica, arial, sans-serif;]@cutlass: Now that SL released their smartwatch, shall we join in realizing my daydream? [/color] :rolleyes: 

 

I've actually been working on a similar thing on and off for some time now. It has a lot of potential but the road is still long.




#49742 My daydream - FPGA/ARM platform

Posted by hanzibal on 22 May 2013 - 01:16 AM in General Discussion

I have a TI watch laying in its box somewhere inside a bigger box. I'm a softie by profession but always loved the interaction with hardware. Trying to make complicated hardware look and feel simple is a really fun challange. A problem I have is that whenever I get an idea (and I constantly do), I pursue it with great frenzy but when I get to the point of actually having etsablished a proof of concept, I sometimes loose interest since I can pretty much imagine the rest. With certain things I don't see all that big a difference between stuff in my imagination and that of the real world. Don't get me wrong now, I'm not hearing voices or anything :-) Work is a game of wrestling with matter, trying to force it into the structures I've imagined, sometimes I win and sometimes matter does. When it comes to this dream project of mine, I don't have a proof of concept yet but given recent info, I'm starting to imagining it :-)

 

I guess I'm saying that I know my self only too well, I'm quite good at getting passed mid way. But then of course, there are others who are very good at finishing and that's probably why they invented teams.




#50508 My daydream - FPGA/ARM platform

Posted by hanzibal on 16 June 2013 - 01:54 AM in General Discussion

Seems like a nice board but it's quite understandable that the guy shelved it given the Cypress's new PSoC 4-board which has a lot more features on-board. You just can't compete with that kind of pricing.



#51274 Web Based IR Remote

Posted by hanzibal on 10 July 2013 - 12:57 AM in General Discussion

That is a great example of a very useful Netduino application and nice to see you've finished the project. The optical feedback system was really clever, it's always good when you can keep it non-intrusive.



#49759 My daydream - FPGA/ARM platform

Posted by hanzibal on 22 May 2013 - 07:08 AM in General Discussion

Did you find anyone with decent shipping?, If I order from cypress, it's $35 for an $25 device.. 

Not really but I ordered some other stuff too and broke the free shipping limit at Mouser.




#49758 My daydream - FPGA/ARM platform

Posted by hanzibal on 22 May 2013 - 07:06 AM in General Discussion

Indeed,everytime I read the VHDL code,I feels like I'm reading a netlist of a PCB....

 

Try opening an Eagle schematics file in Notepad. Practically the same thing.

 

Maybe I just made a great discovery: Simply rename from .sch to .vhdl and voilá!

 

:D

 




#49531 New Netduino on its way? (cryptic homepage)

Posted by hanzibal on 18 May 2013 - 02:39 PM in General Discussion

Have you seen the start page? image.jpg Looks like something new is coming... Can any of you decipher the hieroglyphs? Actually, I had a hunch since Stefan has been very quiet for some time now and statistically*, that is a clear signal! *) Based on random samples taken from a population of one (1)





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