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46  Products / Arduino Due / Re: Amplify DAC output to 0v-12v on: June 05, 2013, 03:19:44 am
I've recently been experimenting with something similar. I need to convert the DAC output range 0.55V-2.75V (approx.) to 0V-5V. So the DAC output needs to be offset by -0.55V and have a gain of about 2.3 applied. The best results so far are with a differential op amp circuit. I can feed the DAC into one input, +0.55V into the other and get an output in the range 0V-2.2V. The overall gain of the amp can be adjusted to give a maximum of 5V. There are lots of examples of differential op amp circuits online.

I prefer this to the summing circuit because I don't have -0.55V available.

BTW, I would recommend buffering the DAC output when experimenting with it. I managed to kill one of mine somehow. I think I've read that they are not very robust.
Did you have a schematic for us to look at?
47  Products / Arduino Due / Re: from arduino due prototype to production on: June 04, 2013, 04:50:35 am
hi everyone,
I ave a project in mind and i'm using arduino due to prototype. my question is how can i pass from the DUE schematic to the 'MyProject' schematic? what can i take off from the board? what do i need to leave instead?

For example is the ATMEGA16U2 necessary?
Necessary depence on what you want with the ATMega16U2 can you use the Arduino IDE for automatic programming with the nativ USB-Port you need to clear the SAM by hand.

But necessary is only the SAM the USB-Connector on the nativ port and some wires to ground, if I right the SAM also did not need an external crystal instead.
48  Products / Arduino Due / Re: Amplify DAC output to 0v-12v on: June 04, 2013, 04:39:04 am
I am trying to use an arduino due to control the following dc dimmer for an ac fan.

As far as I understand it the dimmer requires a dc input between 0v and 12v to control the ac fan with 0v stopping the fan and 12v for max speed.

I thought about using the DAC output and amplifying the dac output from the due.

Is this the right way to do it and how do I amplify the signal?

A quick search on Google makes me think that I need an op amp circuit to amplify the signal.  Can somebody point me to a suitable circuit for this or suggest a better alternative?


May really not what you looking for but whats about an sperate IC for it like the AD5501BRUZ (12bit) or the AD5412AREZ (12-16bit) used SPI and take an seperate Voltage for the Output.
49  Products / Arduino Due / Re: BMA020 is always 0 on: May 24, 2013, 07:04:51 am

thanks for your ideas, but unfortunately it does not help.
The module which carries the BMA020 has a level shifter.
I have no external pull-ups (I know they are included on DUE).
I use several other I2C chips single and combined on the DUE.

What's not clear to me, why helps the oszi probe?
Now I use a 33pF SCL to GND. And it works.  smiley-surprise

Sounds for me at all there is ground missing on the BMA020 may somewhere is the ground connection broken by some wire
50  Products / Arduino Due / Re: Due DS1307 circuit. on: May 22, 2013, 07:38:34 am
I've just done this on Eagle and will build it tomorrow as I'm off to work shortly.

Might be useful to other people. 

Did you take a look at this for Levelshifting with MOS-Fet's can save some Resistors and space.
51  Products / Arduino Due / Re: RTC cann't running well in arduino DUE, because DUE's reset connects NRSTB on: May 20, 2013, 08:56:40 am
What if i turn off taiji-uino by powering off and turn on again? Will doing this cause rtc reset?
Yes Sir.
52  Products / Arduino Due / Re: Arduino Due RTC Library on: May 14, 2013, 04:23:22 pm
It seems to happen at this line:

RTC_clock rtc_clock(XTAL);

You're saying that the delay is waiting for the crystal to settle? Shouldn't using the crystal take less than 2 seconds?

In my words NOOOOOOOO!!!

The internal RC is extremly unstable about counting on time he is too slow. You will loose time.

May use the Teensy 3 who sets faster up in combination with the time lib
53  Products / Arduino Due / Re: Arduino Due RTC Library on: May 14, 2013, 03:18:37 pm
One thing I noticed when using this library: Instantiating the rtc object seems to hang the program for about 2 seconds. This didn't work for me in the project I'm working on because it needed to start processing input right away. I didn't trace down why it took so long. Is that normal to take 2 seconds?

If you give me a hint may I can help is it this part?

// Select the Slowclock source
//RTC_clock rtc_clock(RC);
RTC_clock rtc_clock(XTAL);

or does it came from this line?


By the first part it happend about the external xtal to swing-in
54  Products / Arduino Due / Re: cannot set pin 13 mode when using while (!SerialUSB) in setup on: May 08, 2013, 12:42:08 am
Wondering if someone can help me understand what is going on with the code below??

void setup()
  // This seems to ignore the pinMode statement but commenting out the while statement below works fine.
  while (!SerialUSB);
  pinMode(13, OUTPUT);

void loop()
  digitalWrite(13, LOW);

When changing the line above to "while (!Serial);" it works just as if it was commented out entirely.  I read somewhere that you should put while (!Serial); in your setup as a first step to ensure the serial port hardware is initialized before doing anything else with it.  Wouldn't this also be the case for SerialUSB when using the native USB port??

If the while statement on SerialUSB is used at all the digitalWrite statement has no effect and LED always stays on.

Yes thats right.

The code lines
while (!Serial);
while (!SerialUSB);

let the Due what until there is an USB connection between Due and PC. If you use the programming port and set this line
while (!Serial);
The Due will walk over this line while the USB is connected but if you connect after the programming the due with the nativ USB-Port nothing will happend the Due waits for an plugin in the programming port.

Vice versa for both ports.
55  Products / Arduino Due / Re: Building a CAN communication protocol interface for Arduino DUE on: April 24, 2013, 08:42:11 am
Quote my self...

SN65HVD233 has the Loopback funktion

SN65HVD234 has the Standby mode and the

SN65HVD235 has the Autobaud option,

you need to choose the Chipfunction you want, but the SAM supports Autobaud and Sleepmode only the Loopback funktion is missing.

I did not know if the functions allready implemented in the library, but compared to the functions of the SAM and the TI Transciever I would choose the the SN65HVD233 to make it complete without having some option 2 times
56  Products / Arduino Due / Re: Taiji-Uino Due RTC broken? on: April 24, 2013, 12:42:06 am

I wanted to use Markus's really nice RTC library on my Taiji-Uino Due but the code is not working. 

Here is his library:

If I run the example "Due_RTC_Simple_Sample", I do not get anything back on the serial monitor.  However, If I plug in my Arduino brand Arduino Due, I get results like I expect from the example sketch.

I have a second Taiji-Uino and that one is having the same problem...  Maybe I got a couple of them from a bad batch?

Can someone else with a Taiji-uino Due verify what I am seeing?
Hi kcore,

did you check this line?

// Select the Slowclock source
//RTC_clock rtc_clock(RC);
RTC_clock rtc_clock(XTAL);

In the Sample may the Taiji-Uino has no crystal on the surface, so that you need to choose the RC.


57  Products / Arduino Due / Re: OneWire in Due on: April 18, 2013, 03:13:01 am
Your best chance is OneWire 2.2 with the latest nightly build of Arduino.
Yes that works just changing a few files and the new OneWire lib from Paul and the Due is working correctly.
58  Products / Arduino Due / Re: Synchronous Port Manipulation on Due on: April 16, 2013, 02:50:48 pm


    for( k = 44 ; k <= 51 ; k++ )
      pinMode( k, OUTPUT ) ; // Sets Port C12-C19 to output pins. Necessary or no data is written.
    for( k = 34 ; k <= 41 ; k++ )
      pinMode( k, OUTPUT ) ; // Sets Port C2-C9 to output pins

Is there a list of which due pins correspond to which port registers?

May a little bit inconvenient but you can put it yourself together from the Pinout,132130.0.html
59  Products / Arduino Due / Re: [Finally a working EMAC library] Connecting an Ethernet PHY to Arduino Due on: April 15, 2013, 11:15:08 am

Hope it could make things easy
An little bit barely an explanation.
60  Products / Arduino Due / Re: RTC cann't running well in arduino DUE, because DUE's reset connects NRSTB on: April 14, 2013, 12:13:44 pm
Your right about the reset, but I doubt that will ever be changed. If you can wait 6 months my board allows both types of reset smiley

A half year? How would I spent the time, waiting is so uncomfortable...
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