NimbeLink Microchip chipKIT WF32 Shield User manual

Microchip chipKITTM WF32 Shield
User Manual
NimbeLink Corp
Updated: August 2016
PN 30089 rev 2© NimbeLink Corp. 2017. All rights reserved. 1

Table of Contents
Introduction 3
Overview 3
Product Description 3
Additional Resources 4
Technical Specifications 5
Block Diagram 5
Pinout 6
Table 2.2.1 Shield Default Pinout 6
Getting Started 7
Operating Modes 7
UART Configuration 7
Sensor Connections 7
Required Hardware 8
Mounting the Shield 8
Skywire Placement 10
Programming the chipKIT board 11
Viewing the Device Data 12
Troubleshooting 12
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1. Introduction
1.1 Overview
This document is the User Manual for the Skywire® Sensor Shield when used
with chipKIT WF32 development kit. Throughout the document Skywire Sensor
Shield will often be referred to as 'the shield', although it may be referred to by its
full name.
The NimbeLink Skywire modem is available with bundled data plans from leading
cellular carriers. The Skywire cellular modem and antennas are sold separately.
Make sure you check NimbeLink's Skywire Sensor Shield product page for the
most up to date information
1.2 Product Description
Connect the Microchip WF32 development platform to the Internet of Things
(IoT) quickly and easily with NimbeLink's Skywire Sensor Shield. Whether you
are a hobbyist or a developer preparing a product for launch, NimbeLink's shield
and your choice of NimbeLink Skywire plug-in cellular modems will provide the
cellular connectivity you need. With Cellular connectivity, several included
sensors, and example code you can have your proof of concept up and running
in minutes with a clear path to production.
● Skywire socket that supports 2G, 3G, and 4G modems
● NimbeLink’s certified modems and bundled data plans can have you
connected to the network faster than any other cellular solution
● Four sensors to demonstrate your IoT solution (Temperature,
Acceleration, Pressure, and Humidity)
● Example code to upload sensor data to Verizon Thingspace.io
dashboards
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1.3 Orderable Parts
Orderable Device
Description
Manufacturer
Carrier
Network Type
NL-AB-ST-NCL
Skywire Sensor Shield (includes
antenna and power supply)
NimbeLink
NL-SW-1XRTT-V
Skywire 1xRTT Cellular Modem without
data plan. 2G Modem.
NimbeLink
Verizon
2G CDMA 1xRTT
NL-SW-EVDO-V
Skywire EVDO Cellular Modem without
data plan. 3G Modem.
NimbeLink
Verizon
3G CDMA EVDO
TG.30.8113
Cellular Antenna
Taoglas
TDGL021
chipKIT WF32 IoT development kit
Microchip
1.4 Additional Resources
● NimbeLink's Skywire Sensor Shield Product Page
● NimbeLink's Skywire Sensor Shield Schematic
● NimbeLink's Skywire 2G 1xRTT Product Page
● NimbeLink's Skywire 3G GSM/HSPA+ Product Page
● NimbeLink's Skywire 3G CDMA/EVDO Product Page
● Microchip chipKIT WF32 Platform Page
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2. Technical Specifications
2.1 Block Diagram
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2.2 Pinout
Table 2.2.1 Shield Default Pinout
Pin Name
Header
Shield Connection
IO0
IOL
Skywire DOUT
IO1
IOL
Skywire DIN
IO2
IOL
No   Connect
IO3
IOL
Button 1
IO4
IOL
LM75 INT
IO5
IOL
LIS3DH INT1
IO6
IOL
HTS221 DRDY
IO7
IOL
LPS331 INT1
IO8
IOH
No   Connect
IO9
IOH
Skywire Reset
IO10
IOH
Skywire DTR
IO11
IOH
Skywire RTS
IO12
IOH
Skywire ON/OFF
IO13
IOH
Skywire CTS
GND
IOH
GND
AREF
IOH
No   Connect
SDA
IOH
I2C_SDA
SCL
IOH
I2C_SCL
All Pins
AD
LEDs/Analog Sensors
VIN
POWER
12 V Input
GND
POWER
GND
5V
POWER
5V Input (unused)
3V3
POWER
3.3V Input
RESET
POWER
No   Connect
IOREF
POWER
Skywire Vref
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3. Getting Started
3.1 Operating Modes
NimbeLink's Skywire Sensor Shield is designed to be compatible with the
Microchip chipKIT WF32 board. The shield also provides headers to plug in
additional shields to further the platform's functionality. The user must ensure the
pins on expansion shields do not interfere with the pins of the Skywire Sensor
Shield.
3.1.1 UART Configuration
By default the UART connection between the Skywire and the chipKIT board
connects to UART1. The default debug interface also uses UART1 so it is
important to avoid using this line for both communications. It is recommended
that UART4 (Pins 39/40 on the chipKIT WF32 Board) be used for the debug
UART in order to avoid interference. This can be done with an external Serial to
USB cable, for example.
The Skywire defaults to an 115200 BAUD rate, 8 bit data, no parity, and 1 stop
bit. The Data Terminal Ready (DTR) and Ready To Send (RTS) lines must be
driven low from the WF32 to the modem.
3.1.2 Sensor Connections
The shield has four sensors connected to Analog/IO pins that can be polled by
the chipKIT board .
The shield also has four sensors connected to the I2C interface coming from the
chipKIT board. The shield provides 4.75K pullup resistors on the I2C interface.
On the chipKIT board used in this startup guide, the I2C interface is on pins 45
(SCL) and 46 (SDA).
See the table below for details on each sensor.
Sensor
Function
Pin
PhotoTrans
Returns the amount of
surrounding light, value = 0-1023
AD0
Button 1
A digital read of the pin returns a 1
for closed, a 0 for open
IO3
Button 2
A digital read of the pin returns a 1
for closed, a 0 for open
AD4
Potentiometer
Adjustable voltage divider changes
output by rotating, value = 0-1023
AD5
HTS221
Humidity 0-100% RH
I2C
LIS3DH
3-Axis Accelerometer 2g/4g/8g/16g
I2C
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LPS331
Pressure
260-1260mbar
I2C
STLM75
Temperature
-55C to 125C
I2C
3.2 Required Hardware
This guide assumes the user has access to the following hardware:
● Skywire chipKIT Cellular Sensor Shield
● chipKIT WF32 Demo Board (or equivalent)
● 12 V power supply
● USB A to mini-B connector (for programming the chipKIT  board)
● Cellular antenna
● Optional: USB-to-Serial cable (for debugging)
3.3 Mounting the Shield
Before mounting the shield, verify that the following jumpers in particular are in
the correct positions as shown in the figure below:
Figure 3-1: correct jumper positions for chipKIT board.
J15: jumper should be in the ‘EXT’ position. This allows the shield to be powered
off of the chipKIT board’s external 12 V supply port instead of the USB port.
JP4/JP5: jumpers should be in the ‘AN’ positions to disconnect the I2C bus from
the analog sensor ports.
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The Shield is designed to interface with the Arduino compatible headers on the
chipKIT development board. To mount the shield, orient the pins correctly over
the Arduino headers and press down on the shield until the shield is seated fully.
There should be no unconnected pins below the shield.
Figure 3-2: chipKIT board and Skywire Shield proper orientation
Figure 3-3: Skywire Shield mounted on chipKIT board
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3.4 Skywire Placement
The Skywire Cellular modem is designed to be placed as shown below.
Figure   3-4:   Skywire   Sensor   Shield   with   Skywire   3G   EVDO   Modem
To mount your Skywire Cellular modem follow these steps:
1. Gather the following:
a. Skywire Sensor Shield
b. Skywire Cellular Modem
c. U.FL extractor tool (Always use a U.FL extractor tool when placing or
removing U.FL cables on the Skywire modem to avoid damaging the U.FL
connectors).
2. Line up the Skywire cellular U.FL connector(s) with the circles inside the
shield’s Skywire socket footprint. Depending on the type of Skywire Modem there
may be one or two U.FL connections.
3. Carefully seat your Skywire into the shield’s Skywire socket (J6). Take care to
ensure that the pins are correctly aligned. Failure to properly align the pins may
damage your Skywire!
4. Attach the U.FL cable to the U.FL connector marked X1 on the Skywire
modem.
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3.5 Programming the chipKIT board
To program the chipKIT board while the Skywire Shield is mounted, remove the
jumpers from J3 and J4 on the shield to disconnect the Skywire modem from the
serial communication lines used for programming. Then, download the chipKIT
board software, MPIDE, from the chipKIT website:
http://chipkit.net/mpide
and follow the steps below to program the chipKIT board:
● Follow the MPIDE installation guide referenced on the MPIDE download
page (Windows, Mac, Linux)
● Download the Skywire_chipKIT_Dweet.zip file from
http://nimbelink.com/drivers/Skywire_chipKIT_Dweet.zip
● Extract the zip file to the MPIDE sketchbook folder, located by default in your
“My Documents” directory
● Within MPIDE, open the extracted pde file: ‘File -> Open ->
Skywire_chipKIT_Dweet -> Skywire_chipKIT_Dweet.pde
● Remove jumpers from J3 and J4 on the shield
● Power the chipKIT board and shield using the external 12 V power jack
● Connect the chipKIT board to your computer via USB
● Within MPIDE: Select ‘Tools -> Serial Port -> COM#’ (where # corresponds
with the COM port assigned to your chipKIT board)
● Select ‘Tools -> Board -> chipKIT board -> chipKIT WF32’
● Select the ‘Upload’ button
● Wait for the upload to finish. The LD1 and LD2 LEDs should be flashing
during this process
Before running:
● Disconnect USB cable from the chipKIT board
● Unplug the power cord from the chipKIT board and shield
● Reconnect jumpers on J3 and J4
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Left: programming configuration; Right: normal operation
3.6 Viewing the Device Data
Once your chipKIT board is programmed and has a mounted shield, the following
steps can be used to view the data being posted to the cloud by your device:
● Make an account at https://freeboard.io/ if you do not already have one
● Go to https://freeboard.io/board/6Xxpac and make a copy of the dashboard
by clicking on the "Clone" button in the lower right corner
● Open the cloned dashboard and click on "skywire" under "Datasources"
● Replace the "Thing Name" field with your modem's MEID or IMEI and select
"Save"
● Power on your chipKIT board and shield and wait for the green LED to start
flashing on the shield
At this point, your dashboard widgets should begin updating in real-time as your
device uploads its sensor data to dweet.io.
3.7 Troubleshooting
If you are unable to view your device's data on freeboard.io after going through
the steps in the previous sections, try the following troubleshooting options:
PN 30089 rev 2© NimbeLink Corp. 2017. All rights reserved. 12

● Make sure the shield has jumpers on J3 and J4 to allow the chipKIT board to
send serial commands to the modem.
● If the shield's green LED is flashing, verify that the data is being uploaded to
dweet.io by going to https://dweet.io/get/latest/dweet/for/<thingname>, where
<thingname> is replaced by the MEID or IMEI of your modem. If your
device's data is displayed there, check that the correct thing name is entered
under the "Data Sources" section of your freeboard.io dashboard.
●The following requires a USB-to-UART Serial cable: If the green LED is
not flashing, power off the chipKIT board and remove the shield. Then, place
a wire in pin 40 on the chipKIT board and re-mount the shield. Connect the
"GND" wire of the USB-to-Serial cable to J4 on the chipKIT board (ground)
and the "RX" pin to the wire in pin 40 of the chipKIT board. Power on the
chipKIT board and shield. Using a terminal program such as Tera Term or
PuTTY, open a serial connection with 115200 BAUD, 8-bit, no parity, and 1
stop bit to view the debugging trace statements from the chipKIT board.
● The following requires a Skywire Development Kit: Follow the
instructions at
http://nimbelink.com/wp-content/uploads/2014/08/User-Manual-Skywire-Dev
elopment-Kit.pdf
to verify that your modem is activated and is able to connect to the cellular
network.
PN 30089 rev 2© NimbeLink Corp. 2017. All rights reserved. 13