Connect UDOO Neo board to Avnet M14A2A Cellular Shield

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jpavnet's picture
jpavnet
Junior(0)

I have this 'UDOO Neo' board that provides Arduino UNO pinouts, and I want to connect it to 'Avnet M14A2A Cellular Shield' which I believe has Arduino UNO R3 pin layout.
I am contemplating on whether I can connect the cellular shield to UDOO Neo, since both have Arduino pinouts and wanted to know if there are any issues in doing that.

Power Management:
    Avnet M14A2A Cellular Shield     - power in from microUSB (5v / 2.4A)
    UDOO Neo (expects 5v / 2A)       - gets power from shield

GPIO:
    Avnet M14A2A Cellular Shield     - 3.3v
    UDOO Neo                                - 3.3v

 

1. Is my assumption correct that the shield can supply power to Host (UDOO Neo)?

2. Is there any other aspect to be considered to check the compatibility?

    
   

LightCollector's picture
LightCollector
Moderator(20)

Hi,  You would need to have a 4.4A power supply to feed both.  It MAY be possible to power both with careful wiring.  You will have to look at the shield and UDOO board schematics.  You will have to locate the power pins on the shield and the serial UART TXD, RXD pins. Those are the easy ones, you don't need to use RTS/CTS.

 

You will have to also locate several GPIO pins that are used to power up the 14A2A.  There are level translators that need enabled and some pins to boot the 14A2A into serial uart mode.  You can look in the out of the box demo source code Avnet_ATT_Cellular_IOT in the module cell_modem.cpp there is a function mdm_init() (mbed libraries found here: https://developer.mbed.org/teams/Avnet/ ).

 

I'm not familiar with the UDOO.  But if you have an USB OTG connector and you have drivers for a USB ACM Serial UART, you can power up and use the shield without using any of the Ardunio shield pins.  A usb Y cable could be used to power both with a big enough 5V supply.  The AT commands are exactly the same for the serial UART and the USB serial UART.

 

Best Regards

jpavnet's picture
jpavnet
Junior(0)

Thanks for the detailed reply.

Based on what you suggested, I guess I will have to follow the same approach as RaspberryPi <--> 14A2A being used together. This was my first impression as well but I was just wondering if both sides have Arduino UNO pins and same logic levels in/out then probably they might work seemlessly. 

LightCollector's picture
LightCollector
Moderator(20)

You can possibly make either path work, Arduino pins or USB Serial.  Just to be clear, the Pi to 14A2A is yet different.  The 14A2A instantiates a cdc_ether driver and the Pi uses that to send data with. The Pi also can access the 14A2A with AT commands through the USB serial connection but the out of the box kit for Pi 3 does not currently use AT just the cdc_ether.  If your other board can talk to an cdc_ether device that is another way.  Make sure you setup the 14A2A with the correct APN setting before attempting to use it for any data with any of the methods.  How to do that is detailed differently for the different kits, it is done with the command: AT%PDNSET=1, "m2m.com.attz".

 

Best Regards