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Topic: Conflicting documentation: WiFi Shield IO usage (Read 958 times) previous topic - next topic

c1221r

I'm currently using the Arduino WiFi shield for a project. In addition, I'll be stacking on a ProtoShield with some custom circuitry. I need to decide which IO pins to use for my custom shield that do not conflict with the WiFi shield. (Note: i'd prefer to use Leonardo, but may regrettably have to go to the larger Mega 2560 for the extra IO if these conflicts prevent me from having enough IO for my shield).

PROBLEM: Arduino.cc has conflicting information on the WiFi shield IO connections! I'd appreciate any feedback in sorting out the differences, and if any info is incorrect I also need to make sure the WiFi library doesn't try to control unconnected IO as it will interfere with my own hardware!

1) on the WiFi page (http://arduino.cc/en/Main/ArduinoWiFiShield), the description and picture show the following connections:
pin4: SS(SD card)
pin7: Handshake
pin10: SS(WiFi)
pin11: MOSI
pin12: MISO
pin13: SCK

2) The WiFi shield schematic, however, has a different opinion. Differences:
pin3: INT1 (I assume this is the handshake signal moved from pin 7??)
pin7: no connection!!
pin9: yellow LED (buffered)
pins11-13: no connection!!
pin-analog5: used as part of the reset circuit?
-> using SPI bus on the ICSP connector rather than pins11-13?

Can anyone shed some light on the inconsistencies?

johnwasser

On the UNO the SPI connections on the ICSP connector are ALSO on Pins 11, 12, and 13.  On the Mega they connect to 50, 51, and 52 which is why the ICSP header is used.

Botom line:  You can't use 11, 12, or 13 for other things while using the ICSP SPI pins.
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pylon

The schematics and the eagle files seems to be an older version. On both the pin 3 is used for the handshake signal while in the final library and in the pictures of the board the INT connection is going to pin 7. The documentation on the linked page seems to be correct, but the schematics and board files linked there are not.

RudyR

Found this post trying to figure out the same documentation discrepancy.  Handshake is definitely pin 7 on my board.

This thread and the following links helped me figure out the connection, posting here for those following the same google trail:

Comparing the backside picture of the R3 Wifi shield at http://arduino.cc/en/Main/ArduinoWiFiShield with my (R3) board, there is no rework jumper connected to Pin 7 (WiFi Handshake) in the picture.

There is rework wire on my board (to Pin 7). This rework matches the picture (also R3) at http://media.digikey.com/pdf/Data%20Sheets/Arduino%20PDFs/ArduinoWiFiShield_Web.pdf.
This signal did connect to Pin 3 at some point in time.  The original connection to Pin 3 on my PCB is cut.

The 3rd picture down in both documents shows handshake on Pin 7.

And the example code works.

Regards,
Rudy

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