LPCXpresso tutorials

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jamesmatthew
 
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LPCXpresso tutorials

Post by jamesmatthew »

Any plans to create Adafruit tutorials for the LPCXpresso boards that Adafruit sells? I know that NXP has lots of code samples, but it's still somewhat cryptic for those moving from something like Arduino.

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adafruit_support_mike
 
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Re: LPCXpresso tutorials

Post by adafruit_support_mike »

I don't know of any plans offhand.. we're still busy trying to port code to the Arduino Due, get stuff running on the RasPi, etc.

Kevin is our real LPC master, but he's also one of our NFC-and-inductive-circuit-voodoo mavens. He's busy enough that I think he only sleeps on alternate Tuesdays.

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Franklin97355
 
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Re: LPCXpresso tutorials

Post by Franklin97355 »

There looks to be several of these that might help. https://www.google.com/search?q=LPCXpre ... age=1&rlz= You may need to do some searching to find those that fit your level of expertise.

ilovefpv
 
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Re: LPCXpresso tutorials

Post by ilovefpv »

In my experience the LPCXpresso is fantastic hardware with a great very low cost debugger, but....

* The C language environment is not for beginners - especially the lack of the Wiring library for Arduino..
* The library is nothing compared to Arduino
* The community which supports it is nothing compared to Arduino
* The CodeRed RedLib ties you into a propriety closed source library and doesn't allow C++ without $$

Ok, so why use it?

Well for $1.32 you have a 32bit 50 Mhz microprocessor (LPC1114) in a DIP package with full debug support.. Frankly this is amazing. In some ways I am surprised the Due went from the AVR all the way up to the M3 instead of starting with the M0.

Anyways I'm really into the LPC1114 (and will be interested in the LPC810). Attached is my breadboard setup:
LPC1114 Breadboard Setup
LPC1114 Breadboard Setup
IMG_1692.jpg (119.89 KiB) Viewed 2264 times
I'm not using the LPCxpresso IDE or Code Red at all. ARM is now sponsoring a GCC toolchain (C and C++) which to date is showing really great professional support: https://launchpad.net/gcc-arm-embedded. Right now I'm just using old-school gcc with some DOS scripts I made up.

If anybody is interested in learning more just let me know.

-Steve
http://www.ilovefpv.com

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jamesmatthew
 
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Re: LPCXpresso tutorials

Post by jamesmatthew »

Steve,

I agree that these are a good value- for about the cost of an Arduino Uno, you can get an LPCXpresso dev board with much more power. I like the IDE also - I can live without C++ for what I'm doing and the Eclipse-based IDE is nice. (I read somewhere that NXP is replacing the Code Red with their own tools, so maybe the parts that you don't like will go away - or maybe not...)

The C language doesn't bother me. I've used it off and on for years and don't have many problems in non-embedded use. The lack of libraries is a problem - the Arduino shields (no pun intended) the user from low level stuff and there are nearly unlimited resources to fall back on, but the LPC requires the user to know more. That's not a bad thing - it's part of the reason that I want to use it. (I think that I could get similar power with less headaches by using mbed, but headaches are part of the fun.) And I'm not completely lost - I've been able to blink LEDs and move servos, but it's half by luck instead of knowledge.

So, if "Kevin the LPC master" ever happens to have insomnia on one of those alternate Tuesdays, some basic tutorials would be welcome.

ilovefpv
 
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Re: LPCXpresso tutorials

Post by ilovefpv »

I've got quite a bit of experience with the LPCXpresso tools (with both the LPC1114 and LPC1769)..

Is there something specific you need help with?

There is a huge gap between Arduino and LPCx. It would be incredibly helpful if the Arduino pin mapping was assigned to the LPCx processor with some of the key elements of wiring. The pin mappings are fairly close. Maybe something like this:
Arduino_LPC1114.png
Arduino_LPC1114.png (138.93 KiB) Viewed 2198 times
I don't think it would be a huge effort to port this over.

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jamesmatthew
 
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Re: LPCXpresso tutorials

Post by jamesmatthew »

Thanks for the offer - and the pinout comparison - I like that.

I don't have specific questions. I haven't looked at my LPC1769 board in months and only started thinking about it again when I noticed that Adafruit was selling them. I do have one general question, though.

Do you know much about watchdog timers? And what the state of the timer is "out of the box"? The last thing that I did with my LPC1769 was to attempt to make a sun tracking device for a solar panel using two servos and four photo resistors (I certainly didn't need the power of an LPC1769 for this, but was using it as a learning aid). It would work for a few minutes or seconds, then freeze up and would require power cycle to go again. My only guess for the cause was that a watchdog timer wasn't being refreshed (but that was just a wild guess). My attempts at reading the documentation make me think that the watchdog is disabled by default, but I'm not sure. I was not setting any timers in the code (mostly because I didn't know how to initiate it).

ilovefpv
 
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Re: LPCXpresso tutorials

Post by ilovefpv »

The watchdog timers will be off by default (in fact that is the case for all the timers).. Doesn't sound like it to me - unless you turned it on...

What are you using to power this system with? Most importantly what is powering the LPC1769?

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jamesmatthew
 
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Re: LPCXpresso tutorials

Post by jamesmatthew »

I know that I didn't turn on the watchdog timer - timers were one of the many things that was confusing me. In fact, the interval for checking the state of the photo resistors was done with a for loop because I couldn't set up a timer. I'll try to find the old code and post it to verify.

The 1769 board was running off the USB cable. The servos were powered by a separate power supply.

ilovefpv
 
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Re: LPCXpresso tutorials

Post by ilovefpv »

Hi James,

Here's a write up on this topic we were discussing over the summer:

http://www.ilovefpv.com/2013/10/bread-b ... 114-dip28/

Hope this helps..

-Steve

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jamesmatthew
 
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Re: LPCXpresso tutorials

Post by jamesmatthew »

Steve,

That's a great tutorial. Thanks for the information.

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