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6391  Using Arduino / LEDs and Multiplexing / Re: Possible to operate a shift register manually with switches? on: May 24, 2011, 04:42:28 am
Quote
as the pins need to be kept HIGH for the relevant cycle and then set LOW again
Which pins?

The only one that matters is the clock and it's edge triggered, so whether you give it a short high pulse or a short low pulse as far as the eye is concerned the SR will update the same way.

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Rob
6392  Development / Other Hardware Development / Re: ATMEL Mega1284P evaluation board avalible on: May 22, 2011, 09:55:12 am
Nice-looking layout, not auto-routed I'm guessing.

I can't read the schematic, are you using an inductor on AVCC?

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Rob
6393  Community / Exhibition / Gallery / Re: Modular Stackable Microcontroller System (lots of pics) on: May 21, 2011, 09:25:07 pm
Yep I'd stick with a single master.

On my modules I have them report all sorts of "vendor" info such as serial #, SW and HW revision, revision for the system the board is tested for, plain English name for the board, full vendor name, abbreviated vendor hame, unique board type number so a plug in diagnostic device can know exactly what the board should do etc. 

I suppose you will only have one "vendor" so don't need lots of that but I'd certainly add revision numbers etc. If you make lots of these you'll quickly lose track of what's what.

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Rob
6394  Community / Exhibition / Gallery / Re: Modular Stackable Microcontroller System (lots of pics) on: May 21, 2011, 08:07:24 am
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starting another mode in the Processor will clear all addresses on the modules by way of a broadcast to Address 0.
If you only want to reset one board pull all the others before you broadcast this.

OR (and better)

You'll have some form of monitor running on the main processor I assume, so you can see what boards are there etc. And you already have code to get a board to change from 119 to N, can't you just get it to change from N to 119 and do this as a command in the monitor.

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Rob
6395  Using Arduino / Sensors / Re: ADS1252: Tutorial on High precision (24-bit) ADC on: May 21, 2011, 05:02:50 am
What I would like to know is the accuracy achieved with no obvious ground planes etc.

From everything I've read getting the full 24 bits is a real black art, OTOH all the data sheets just show the chips hooked up and they state an ENOB of 23.5 bits or whatever with no mention of PCB design or anything.

I would like to get some more definitive info about this.

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Rob
6396  Using Arduino / Microcontrollers / Re: Similar Microcontrollers to Arduino/Atmega?? on: May 21, 2011, 04:02:30 am
So there's more than one way to skin a cat.

I don't think you'll win over many beginners with that code though smiley

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Rob
6397  Using Arduino / Microcontrollers / Re: Similar Microcontrollers to Arduino/Atmega?? on: May 20, 2011, 10:11:42 pm
That's done it Senso, you've scared joebro right off now smiley

Joe, this is the "bare metal" we've been talking about. The beauty of the Arduino system is that you can start off being protected from all that stuff, for example the above ADC read is simply

x = analogRead(pin_number);

This is very similar to and just as easy as the Picaxe.

As you get more comfortable with the environment you can usually make things more efficient buy working directly with the hardware as Senso has done.
 
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Rob
6398  Community / Exhibition / Gallery / Re: Modular Stackable Microcontroller System (lots of pics) on: May 20, 2011, 08:08:09 pm
@liudr
I've been watching your menu library with interest. I'm currently designing a LCD board (with RS485 for remote displays) and it might be good for that.

Unfortunately I only have room for 4 buttons, is it still a goer without the extra two?

@wanago
Re HMI, I've just got two 4D Systems 3.2" LCD with touch. Serial interface so they would be easy to use.
Re RS485, if you add RS485 all my modules I'm designing should work with your system and give you access to remote sensors, displays, GPS, accelerometers etc. I would still keep RS232 if possible though because there's a lot of legacy equipment you'll need to talk to.

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Rob
6399  Using Arduino / Project Guidance / Re: Arduino controlled tube bending controller on: May 20, 2011, 10:20:56 am
You've might have to be careful how many you drive at the same time. The absolute max for each VCC and GND pin is 200mA, but given that there's 4 or 5 of each on a Mega I don't know if that means 4 or 5x 200mA or not.

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Rob
 
6400  Community / Exhibition / Gallery / Re: Modular Stackable Microcontroller System (lots of pics) on: May 20, 2011, 07:21:49 am
I've done the backplane address thing in the past and it works well enough.

One thing I don't like about that system is that all the addressing changes if you decide card X should be one slot to the left, so all the other cards move up one.

How about a combination of the two approaches.

Every micro-based card has an address in EEPROM that is null to start with. If that value is null the card gets the address from the backplane, if not it uses the EEPROM version.

So cards can spend their life using the backplane address, but if you want some stability you have a utility that tells it to write an address into EEPROM.

Backplane addresses are < 16, EEPROM address 16 to 255 (or whatever).

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Rob
6401  Using Arduino / Sensors / Re: pressure sensitive button - on: May 20, 2011, 03:18:00 am
And linear pots, depending on how much travel you need.

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Rob
6402  Using Arduino / Programming Questions / Re: Simple timed serial event on: May 19, 2011, 11:25:08 pm
Something like this.

Code:
loop () {

   static long LastDataRx;

  if (Serial.available() > 0) {
      Serial.flush(); // assuming you don't care what the data is, just that there was some
      LastDataRx = millis();
   }

   if (millis() - LastDataRx >= 1000) {
      doSomething();
   }

}

Rather than flush the data it would be better to at least test for a valid character if you have control of the transmitted data and/or know what to expect.

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Rob
6403  Using Arduino / Microcontrollers / Re: Similar Microcontrollers to Arduino/Atmega?? on: May 19, 2011, 11:20:16 pm
The Picaxe is a good system but it's nowhere near as versatile as an AVR or PIC, mostly because of the interpreted BASIC. That arguably makes it easier to use for a beginner but also limits what it can do.

However you may not reach those limits, it depends on what you want to do. I've seen some pretty fair projects done with Picaxes.

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Rob
 
6404  Using Arduino / Programming Questions / Re: How does serial handle data. on: May 19, 2011, 07:25:17 pm
Quote
using a wiimote
I have no idea what these are capable of, can you program it to send whatever characters you like?

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Rob
6405  Using Arduino / Sensors / Re: ADS1252: Tutorial on High precision (24-bit) ADC on: May 19, 2011, 10:15:48 am
Any more news on using this chip?

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Rob
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