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Pmod Shield-Uno with WF32 and WiFire


As I work with the chipKIT WF32 and the WiFIre, I find that making external connections to these processor boards is not as convenient as they are for the chipKIT Pro MX7 that has Pmod connectors JA through JF.  Additionally there are limited pins for taking 3.3V/5V and ground off board.  I can only assume that these chipKIT boards were always intended to be used with a shield of some sort. If Digilent makes IO shields specifically for the WF32 and WiFire, please advise. 

Meanwhile, I find the the Pmod Shield-Uno can be used to provide standard Pmod connections provided a few modifications are made. 

1. The bottom side female connectors for JP6-JP8 must be removed because the USB connector J13 on the Wf32 and WiFire are in the way.  This is easily done by gently bending the female connectors on the bottom of the Shield-Uno back and forth until they break off at the surface of the PCB. The schematic diagram for the Pmod-Shield does not show a connection for the center pin of JP6 and JP8.  Can I assume that since JP6 and JP8 do not feed through to the WF32 or the WiFire that A04/A18 and A05/A19 are not functional?

2. I observed that pins 1 and 2 of J3 on the WF32 / WiFire have no connection to J5 on the Pmod-SHield. This appears not to be an issue since J3:1 is not connected and J3:2 has jumper to J3:4.  

3 J6 of the WF32 / WiFire has no connection to the Pmod-Shield making connections to I2C2 unavailable. I could not find a secondary connection for SCL2 and SDA2.

4. Although the majority of the processor programming is done in the Arduino IDE environment using the serial port, there are times that debugging with the MPLAB X IDE is beneficial. Hence, I permanently soldered a single row right angle 6 pin header in JP2.  This allows me to slip on and off a chipKIT programmer without removing the shield. Do you for see any problems such as RFI emissions?   

5. Reading through the Pmod Shield-Uno users manual I see that the signal names for JA and JB are the same. The chipKIT pin numbers appear to be correct. Digilent should update the users manual.

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Hi Flyline,

I don't believe any shields exist that are specifically designed for the WF32 or the WiFire; the closest options that exist are the Pmod Shield-Uno that you found, the Basic I/O Shield, and the Motor Shield, but the latter two shields are very application specific so if you are looking for a more custom option than that, probably the closest thing would be the protoshield for the Uno32 where you solder on your own custom headers. To be sure, it's not ideal, but an option nonetheless.

As for your questions:

1. Because the WF32/WiFire do not have the jumpers like the Uno32/uC32 have for the A4/A5 vs i2c connection, but instead have the USB connector, the A04/A18 and A05/A19 will not be functional on the Pmod Shield Uno.

2. You are correct in your assessment.

3. I also cannot find another SCL2 and SDA2 since the WF32/WiFire doesn't have those on chipKIT pins 39 and 40 like the Uno32. Your best bet would be to get right angle headers from J6 to outside the board I think.

4. I'm not sure on the RFI emissions, I'll ask around and see if there are any immediate concerns for having both WiFi and some debugging occurring at the same time.

5. I'll go ahead and fix the signal names now, thank you for catching that!


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