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Topic: Arduino Uno R3 and many devices (Read 974 times) previous topic - next topic

VMwareUser

Apr 16, 2013, 07:23 pm Last Edit: Apr 16, 2013, 07:36 pm by VMwareUser Reason: 1
Hello,

Is it possible to connect all these devices together to Arduino Uno R3?
1. W5100 Ethernet
2. nRF24L01 +
3. lcd hd44780

If this is not possible with Ardiuno uno,
Which controller should I use?

Thank you

KeithRB

By adding a serially controlled LCD instead of the hd44780, you can save a lot of pins.

VMwareUser

Thank you for the quick reply,
If I use the serial LCD, I can connect the Ethernet W5100 + nRF24L01 together?

Docedison

Because of the relative low cost of a Mega from Ebay... I'd plan on that platform.. I own one genuine Uno R3... My first Arduino and 2 clone Mega's 3 clone Pro mini's and another clone Uno R2 and I'm not bragging here but I use the Pro's to develop and test sketches and either the Mega's or the Uno's and If necessary a bread boarded 328 is quick and easy. if it gets bigger I use the Mega's for both test and final device. It's cheaper to buy an Ebay Mega than it is to build a board with an ATMega 1280 or 2560 unless I want to build 10 of them...
My point is to fit the device / platform to the job first.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

VMwareUser

Thank you,
it is possible to connect all the devices to ATMega 2560?

fungus


Thank you for the quick reply,
If I use the serial LCD, I can connect the Ethernet W5100 + nRF24L01 together?


Yes.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

VMwareUser



Thank you for the quick reply,
If I use the serial LCD, I can connect the Ethernet W5100 + nRF24L01 together?


Yes.



How to connect Ethernet W5100 boards and the nRF2401+ both to Mega 2560?
How much SPI connections exist?
Thank you

Docedison

One in hardware but it's a bus... you just need a different CS pin for each device... Or you can bitbang the spi data in software and make as many as you like.

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

VMwareUser


One in hardware but it's a bus... you just need a different CS pin for each device... Or you can bitbang the spi data in software and make as many as you like.

Doc


OK, So why Maga 2560 is better than arduino uno ?or this project? Because he has more devices pins?

Thanks!

fungus


OK, So why Maga 2560 is better than arduino uno ?or this project? Because he has more devices pins?


I don't think it's better.

Every SPI device has three wires which it shares with other devices and a unique wires to select that device for communication. Five pins can communicate with two devices, six pins for three devices, etc.

Connecting several SPI devices to an Arduino Uno is no problem.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

VMwareUser

#10
Apr 19, 2013, 04:00 pm Last Edit: Apr 19, 2013, 04:10 pm by VMwareUser Reason: 1
I see, thank you :)
Are all unused digital pin can be used as the CS pin?
Are there Cons connecting multiple devices to SPI?
Which limit the amount of devices that can be connected to SPI? Depending on the amount of available digital pins the controller?

fungus


I see, thank you :)
Are all unused digital pin can be used as the CS pin?


Yes.


Are there Cons connecting multiple devices to SPI?


No.


Which limit the amount of devices that can be connected to SPI? Depending on the amount of available digital pins the controller?


You can add shift registers if you need more than that many devices.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

VMwareUser

#12
Apr 19, 2013, 05:07 pm Last Edit: Apr 19, 2013, 05:15 pm by VMwareUser Reason: 1
Thank you so much :)
I found a picture on Wikipedia explaining that.
http://upload.wikimedia.org/wikipedia/commons/f/fc/SPI_three_slaves.svg

Docedison

there is one device related difference. An example would be the IRQ line used by the RFM12B radios (among other radios, the interrupt line from that Phillips 8574 shift register (because it's bi-directional it needs a way to tell or not tell the processor that there is an input change of status..) Strictly speaking fungus's answer answer is most correct but sometimes the device or process requires additional feedback to be sent to the master as the processes being monitored aren't synchronous with the processor's servicing that device..

Bob
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

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