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Newbie Questions


#1

I’m new to electronics though I’ve been programming now for decades and I’ve started playing with the Domino which is really fun.

I have some questions which may seem silly but I just want to understand and get my head around things so bare with me.

Anyhow at the moment I want to know that given a number of shields that can all stack up, for example, my Domino, an ethernet shield and a wifly shield, can they all be used together? How does this affect pin arrangement, i.e if one shield says it uses digital pins 10-13 etc does that mean those pins are now gone for all shields on top of this?

I envision combining a Domino, Ethernet, WiFly, GPS (on a protoboard) and some kind of LCD display along with a battery, can all these co-exist?

Are there areas/things I need to look at?


#2

You need to check what pins are used by a shield, using the driver code or schematics. You can’t use 2 shields if they use the same pins. But you can rewire the shield, hack it, to make it work but then you need hardware experince


#3

The gps can be used (UEXT connector)
http://www.tinyclr.com/downloads/Extension/Broch_GPSExtension.pdf

The LCD display works too. It needs 4 signal pins (you can choose) and a 5V+ and GND

[quote]D4-connect to any digital pin on FEZ
D5-connect to any digital pin on FEZ
D6-connect to any digital pin on FEZ
D7-connect to any digital pin on FEZ
BL_A- backlight, connect to 5V
BL_K- backlight, connect to ground[/quote]

http://www.tinyclr.com/downloads/Component/Broch_2x16LCD.pdf

I do not know what pins are used by the ethernet shield.

This is correct. Hacking means re-routing the pins to the shield. This is not difficult, but you will need some basic knowledge of soldering and electronics.


#4

Thanks for the info I shall take it under advisement.

It does seem the wifly and ethernet shields conflict with digital pins 10-13.


#5

Could you give me the wifly brochure?


#6

Sure it’s listed here:

http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=456

I’m curious, where are the drivers for these things or do I implement them all myself (which isn’t so bad as it means I can wire to the pins I want to the main board right?)


#7

Wifly:
http://www.tinyclr.com/hardware/1/fez-domino/#/grid/item/125/

Ethernet:
http://www.tinyclr.com/hardware/1/fez-domino/#/grid/item/117/

LCD:
http://www.tinyclr.com/hardware/1/fez-domino/#/grid/item/113/

And all components are listed in the corresponding hardware page:
http://www.tinyclr.com/hardware/1/fez-domino/#/grid/1/


#8

[quote]It does seem the wifly and ethernet shields conflict with digital pins 10-13.
[/quote]

You should be OK with both WiFLY and Ethernet shields. Because both of them use SPI communication.
SPI share three pins, 13-MOSI, 12-MISO, and 11-SCK.
pin 10 is CS or Chip Select pin, you can assign different pin for one of your device, for example,
if you want to have CS of the Ethernet to be pin 10, then you can assign CS pin of WiFLY to be something like pin 9. But you have to set pin assignment accordingly in your code.
The good explanation on SPI is in section 17.2 SPI on the EBook. Here is the link,
http://www.tinyclr.com/downloads/Beginners%20guide%20to%20NETMF.pdf

And this is my simple diagram, showing the connections


#9

Interesting thanks for the links.

I’m curious the LCD/button shield says “This board uses pins Di4 to Di9 for LCD and An0 for buttons” however from what I can see in the code it also uses Di10:


BackLight = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.Di10, true);


#10
BackLight = new OutputPort((Cpu.Pin)FEZ_Pin.Digital.Di10, true);

Where
I can only guess that, the pin could be re-assigned to any digital pin.
They probably use the pin to turn on/off the LCD backlight.

one other thing just ignore the Di2 pin connection between Ethernet and FEZ.
I just found out about this in other post:

[quote]According to this http://www.tinyclr.com/downloads/Domino/DFRobot/ethernet%20shield%20SCH.pdf
the pin is not used for now. we are not using interrupts in the beat drivers. It looks like there is a jumper fro this pin so just make sure it is not connected on teh shield or simply bend the pin out so it doesn’t go to FEZ[/quote]


#11

Thanks for the design! I see Di0 is free (COM1) which is what my GPS currently uses so they’d probably be no need to use UEXT for the GPS and could use that instead for the LCD?


#12

You are welcome!
I removed Bluetooth that connected to Di0 and Di1 from the schematic before I posted.
So yes you can connect your GPS there instead.

Looking forward to see your project post on the forum.
Good luck.