WiFi1500CF Plug-In Hardware User Guide JA03-UM-WiFi
Page 12 Rev: P00 Date: 03/13/14
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Specifications subject to change without notice
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4. GPS Module (Optional) continued
4.2 WiFi Module Operation
Hardware set-up requires the following:
- UART connection (JN3 UART). The TX and RX lines are supported on the WIFi1500CF pins 34 (GPS_TX) and 35
(GPS_RX). These interface pins are at VIO voltage levels; the default VIO value is 2.8 volts. The default UART
configuration is 9600 baud, 8 bits, no parity, 1 stop bit (8N1).
- Antenna connection. The JN3 requires that a suitable external GPS antenna be connected to the u.FL connector
on the WiFi1500CF board. The GPS antenna has to be located so as to allows a reasonable ‘view of the sky’ in
order to receive the GPS satellite signals.
- Power. Apply power to the unit by providing 5.0 +/- 0.25 volts across the WiFi1500CF SUPPLY and GND pins.
Basic operation of the JN3 GPS module consists of utilizing the NMEA messages that are output by the module on
the UART interface. By default, the module will output the following NMEA messages on start-up:
Message
Rate
GGA
once per second
GSA
once per second
RMC
once per second
GSV
once every five seconds
NMEA input messages can be used to control a number of the JN3 GPS modules operational characteristics,
including the UART interface parameters, the standard NMEA messages being output, and the rate at which the
NMEA messages are output. See the SiRF NMEA Reference Manual for additional information. Below is a complete
list of the available NMEA messages:
Message
Description
GGA
GPS Fixed Data
GLL
Geographic Position – Latitude/Longitude
GSA
GNSS DOP and Active Satellites
GSV
GNSS Satellites in View
RMC
Recommended Minimum Data
VTG
Course Over Ground and Ground Speed
ZDA
1PPS Timing Message
In addition to the NMEA messages, the JN3 module supports the SiRF One Socket Protocol (OSP) protocol. Please
refer to the Applicable Documents section for further reference material.
