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
PN
30089
rev
2
©
NimbeLink
Corp.
2017.
All
rights
reserved.
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