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Problem with your CuHead WiFi Mega


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#1 jim

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Posted 16 November 2014 - 09:54 PM

Hello,

I have your LinkSprite CuHead WiFi Shield for Arduino Mega that is interfaced to an Arduino Mega 2560.  This is working -- I have successfully compiled and run your various examples including the WebServer, WiServer, SimpleServer, SimpleClient, etc.

The problem comes when other devices (shields) are added to the system.  Now I understand that the SPI bus (Arduino pins 50-53) is the primary interface to the CuHead shield and that the interrupt is hardware/software selectable as follows:
 

INTX0: Arduino pin 2 (port D)
OR
DIG8: Arduino pin 8 (port B)

and in header file "spi.h" one must select either

#define USE_DIG0_INTR
OR
#define USE_DIG8_INTR

By examining the schematic diagram for you product, this interrupt signal (INTX) is then connected to pin 33 (INT) of the MRF24WBOMA chip.
 

However, the problem is that you have ALSO connected Arduino pin 21 (SCL) to the same interrupt line (INTX).  This fact is not documented in any of your supporting literature. This is causing a conflict with other shields that I must include with my system.  The processor simply freezes.  I searched various blogs and online forums for help without any useful results.  I can see no technical reason why the SCL signal is needed by your WiFi shield.

I tried looking through your software to no avail as it is poorly documented.  I also bent pin 21 outward so that it does not connect to the Arduino; in this case, the WiFi shield does not work at all and will not initialize.

So my question is this:  Is there a hardware or software fix for this problem?  Is there someway to remove the SCL signal from going to your board so that my other devices will work properly?  By the way, without your CuHead WiFi shield in the system, my other devices work just fine.  And I have NO conflicts with Arduino pins 7, 8, or 9 that are also being used by the CuHead shield.

Any light that you can shed on this issue will be much appreciated.



#2 chain

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Posted 21 November 2014 - 01:02 AM

The INT of the wifi module need to be connected to Arduino's INTX PIN, or it will not work. 

 

The code https://github.com/l...rite/cuheadmega defined Arduino's INTX0, so it will appear this problem.

 

You can connect the INT PIN of the wifi module to Arduino's other INTX pin, and then the code should be revised.



#3 chain

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Posted 21 November 2014 - 01:24 AM

Please try this way:

 

Bent the WiFi Shield pin 21 outward and connect it to Arduino Mega's Pin 53.

 

Revise the file "spi.h":

 

From: 

wifi mega1

 

To:

wifi mega2





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