Linx Technologies RXM-GPS-F4 User Manual

Download

Page 1

F4 Series

GPS Receiver Module

Data Guide

Page 2

Warning: Some customers may want Linx radio frequency (“RF”)

products to control machinery or devices remotely, including machinery or devices that can cause death, bodily injuries, and/or property damage if improperly or inadvertently triggered, particularly in industrial settings or other applications implicating life-safety concerns (“Life and Property Safety Situations”).

Table of Contents

1 Description 1 Features 1 Applications

NO OEM LINX REMOTE CONTROL OR FUNCTION MODULE SHOULD EVER BE USED IN LIFE AND PROPERTY SAFETY SITUATIONS. No OEM Linx Remote Control or Function Module

should be modiﬁed for Life and Property Safety Situations. Such modiﬁcation cannot provide sufﬁcient safety and will void the product’s regulatory certiﬁcation and warranty.

Customers may use our (non-Function) Modules, Antenna and Connectors as part of other systems in Life Safety Situations, but only with necessary and industry appropriate redundancies and in compliance with applicable safety standards, including without limitation, ANSI and NFPA standards. It is solely the responsibility of any Linx customer who uses one or more of these products to incorporate appropriate redundancies and safety standards for the Life and Property Safety Situation application.

Do not use this or any Linx product to trigger an action directly from the data line or RSSI lines without a protocol or encoder/ decoder to validate the data. Without validation, any signal from

another unrelated transmitter in the environment received by the module could inadvertently trigger the action.

All RF products are susceptible to RF interference that can prevent communication. RF products without frequency agility or hopping

implemented are more subject to interference. This module does not have a frequency hopping protocol built in.

Do not use any Linx product over the limits in this data guide. Excessive voltage or extended operation at the maximum voltage could cause product failure. Exceeding the reﬂow temperature proﬁle could cause product failure which is not immediately evident.

2 Ordering Information 2 Electrical Specications 2 Electrical Specications 3 Absolute Maximum Ratings 4 Pin Assignments 4 Pin Descriptions 5 A Brief Overview of GPS 5 Client Generated Extended Ephemeris (CGEE) 6 Time To First Fix (TTFF) 7 Module Description 7 Power Supply Requirements 7 The 1PPS Output 8 Antenna Considerations 8 Power Control 10 Module Power-up Sequence 11 Module Power-down Sequence 12 Slow Start Time 12 Protocols 13 Interfacing with NMEA Messages 14 NMEA Output Messages 19 NMEA Input Messages 36 Typical Applications

Do not make any physical or electrical modiﬁcations to any Linx product. This will void the warranty and regulatory and UL certiﬁcations

and may cause product failure which is not immediately evident.

37 Master Development System 38 Board Layout Guidelines 39 Pad Layout 40 Microstrip Details

Page 3

41 Production Guidelines 41 Hand Assembly 41 Automated Assembly 43 Resources

F4 Series GPS Receiver

Data Guide

Description

The F4 Series GPS receiver module is a self-contained high-performance GPS receiver. Based on the SiRFstar IV chipset, it provides exceptional sensitivity, even in dense foliage and urban canyons. The module’s very low power consumption helps maximize runtimes in battery powered applications. The F4 Series receiver can acquire and track up to 48 satellites simultaneously in just seconds, even at the lowest signal levels. Housed in a compact reﬂow-compatible SMD package, the receiver requires no programming or additional RF components (except an antenna) to form a complete GPS solution. Five GPIOs are easily conﬁgured through simple serial commands. These features along with the module’s standard NMEA data output make the F4 Series easy to integrate, even by engineers without previous RF or GPS experience.

0.512

(13.00)

GPS MODULE

RXM-GPS-F4

0.087 (2.20)

Figure 1: Package Dimensions

0.591

(15.00)

LOT GRxxxx

Warning: This product incorporates numerous static-sensitive

components. Always wear an ESD wrist strap and observe proper ESD handling procedures when working with this device. Failure to observe this precaution may result in module damage or failure.

Features

• SiRF Star IV chipset

• Built-in jammer remover

• High sensitivity (-160dBm)

• 48 channels

• Fast TTFF at low signal levels

• 5 user deﬁnable GPIOs

• CGEE allows 3-day prediction

• No programming necessary

Applications

• Positioning and Navigation

• Location and Tracking

• Security/Loss-Prevention

• No external RF components

needed (except an antenna)

• No production tuning

• Direct serial interface

• Power down feature

• Compact surface-mount

package

• Manual or reﬂow compatible

• Surveying

• Logistics

• Fleet Management

– –

3/18/2015

Page 4

Ordering Information

Part Number Description

RXM-GPS-F4-x F4 Series GPS Receiver Module

MDEV-GPS-F4 F4 Series GPS Receiver Master Development System

x = “T” for Tape and Reel, “B” for Bulk

Reels are 1,000 pieces Quantities less than 1,000 pieces are supplied in bulk

Electrical Specications

Figure 2: Ordering Information

Electrical Specications

F4 Series GPS Receiver Speciﬁcations

Parameter Symbol Min. Typ. Max. Units Notes

Power Supply

Operating Voltage V

Supply Current l

Peak 130 mA 1

Acquisition 46 mA 1

Tracking 27.5 mA 1

Hibernate 20 µA 1

Ready-to-Start 9 µA 2

Output Low Voltage V

Output High Voltage V

Output Low Current I

Output High Current I

Input Low Voltage V

Input High Voltage V

Input Capacitance C

Load Capacitance C

LOAD

LNA Section

Input Power P

Antenna Port

RF Impedance R

Environmental

Operating Temperature –30 85 ºC

Storage Temperature –40 85 ºC

1.71 1.8 1.89 VDC

0.4 VDC

0.75*VCC

VCC VDC

2.0 mA

–0.4 0.45 VDC

07*VCC 3.6 VDC

5 pF

8 pF

18 dB

50 Ω

Receiver Section

Receiver Sensitivity

Tracking –160 dBm

Navigation –157 dBm

Cold Start –145 dBm

Acquisition Time

Hot Start (Open Sky) 1 s

Hot Start (Indoor) 15 s

Cold Start 32 s

Cold Start, CGEE 15 s

Position Accuracy

Autonomous 3 m

SBAS 2.5 m

Altitude 18,000 m

Velocity 515 m/s

Chipset SiRF Star IV, GSD4e-9411

Frequency L1 1575.42MHz, C/A Code

Channels 48

Update Rate 1Hz default, up to 5Hz

Protocol Support NMEA 0183 ver 3.0, SiRF Binary

1. VCC = 1.8V

2. Initial state after power is applied

Figure 3: Electrical Speciﬁcations

Absolute Maximum Ratings

Supply Voltage V

I/O Pin Voltage +3.6 VDC

Operating Temperature −40 to +85 ºC

Storage Temperature −40 to +85 ºC

Soldering Temperature +225°C for 10 seconds

Exceeding any of the limits of this section may lead to permanent damage to the device. Furthermore, extended operation at these maximum ratings may reduce the life of this device.

Figure 4: Absolute Maximum Ratings

+1.95 VDC

– – – –

Page 5

Pin Assignments

Figure 5: F4 Series GPS Receiver Pin Assignments (Top View)

A Brief Overview of GPS

GPIOD1 GPIOE2 1PPS3 TX4 RX5 GND21

GPIOC6 P17 /RESET8 RFPWRUP9 ON_OFF10

GND 20

RFIN 19

GND 18

NC 17 NC 16

GND 22

GPIOB 15 GPIOA 14

G1 13

VCC 12

P2 11

The Global Positioning System (GPS) is a U.S.-owned utility that freely and continuously provides positioning, navigation, and timing (PNT) information. Originally created by the U.S. Department of Defense for military applications, the system was made available without charge to civilians in the early 1980s. The global positioning system consists of a nominal constellation of 24 satellites orbiting the earth at about 12,000 nautical miles in height. The pattern and spacing of the satellites allow at least four to be visible above the horizon from any point on the Earth. Each satellite transmits low power radio signals which contain three different bits of information; a pseudorandom code identifying the satellite, ephemeris data which contains the current date and time as well as the satellite’s health, and the almanac data which tells where each satellite should be at any time throughout the day.

Pin Descriptions

Pin Number Name I/O Description

1 GPIOD I/O General Purpose I/O. 3.6V tolerant.

2 GPIOE I/O General Purpose I/O. 3.6V tolerant.

3 1PPS O 1 Pulse Per Second. 1.8V level.

4 TX O Serial output (default NMEA)

5 RX I Serial input (default NMEA). 3.6V tolerant.

6 GPIOC I/O General Purpose I/O. 3.6V tolerant.

7, 11 P1, P2 I Pull to 1.8V VCC through 2.2k resistors.

8 /RESET I

9 RFPWRUP O Power State Indicator

10 ON_OFF I

12 VCC P Supply Voltage

13 G1 I Pull to GND through a 100k resistor.

14 GPIOA I/O General Purpose I/O. 3.6V tolerant.

15 GPIOB I/O General Purpose I/O. 3.6V tolerant.

16, 17 NC − No electrical connection.

18, 20, 21, 22 GND P Ground

19 RFIN I GPS RF signal input

Reset Input. Active low with an internal pull-up. Internal reset is preferred; external reset will clear all RAM. 3.6V tolerant.

Power Control Pin. Internal 10k pull-down resistor. 3.6V tolerant.

A GPS receiver receives and times the signals sent by multiple satellites and calculates the distance to each satellite. If the position of each satellite is known, the receiver can use triangulation to determine its position anywhere on the earth. The receiver uses four satellites to solve for four unknowns; latitude, longitude, altitude, and time. If any of these factors is already known to the system, an accurate position (ﬁx) can be obtained with fewer satellites in view. Tracking more satellites improves calculation accuracy. In essence, the GPS system provides a unique address for every square meter on the planet.

A faster Time To First Fix (TTFF) is also possible if the satellite information is already stored in the receiver. If the receiver knows some of this information, then it can accurately predict its position before acquiring an updated position ﬁx. For example, aircraft or marine navigation equipment may have other means of determining altitude, so the GPS receiver would only have to lock on to three satellites and calculate three equations to provide the ﬁrst position ﬁx after power-up.

Client Generated Extended Ephemeris (CGEE)

CGEE is a type of assisted GPS (AGPS) where the receiver uses the ephemeris data broadcast by the satellites to calculate models of each visible satellite’s future location. This allows the receiver to store up to 3 days worth of ephemeris data and results in faster TTFF.

Figure 6: F4 Series GPS Receiver Pin Descriptions

– – – –

Page 6

Time To First Fix (TTFF)

TTFF is often broken down into three parts:

Cold: A cold start is when the receiver has no accurate knowledge of its position or time. This happens when the receiver’s internal Real Time Clock (RTC) has not been running or it has no valid ephemeris or almanac data. In a cold start, the receiver takes 35 to 40 seconds to acquire its position.

Module Description

The F4 Series GPS Receiver module is based on the SiRFstarIV chipset, which consumes less power than competitive products while providing exceptional performance even in dense foliage and urban canyons. No external RF components are needed other than an antenna. The simple serial interface and industry standard NMEA protocol make integration of the F4 Series receiver into an end product extremely straightforward.

Warm or Normal: A typical warm start is when the receiver has valid almanac and time data and has not signiﬁcantly moved since its last valid position calculation. This happens when the receiver has been shut down for more than 2 hours, but still has its last position, time, and almanac saved in memory, and its RTC has been running. The receiver can predict the location of the current visible satellites and its location; however, it needs to wait for an ephemeris broadcast (every 30 seconds) before it can accurately calculate its position.

Hot or Standby: A hot start is when the receiver has valid ephemeris, time, and almanac data. This happens when the receiver has been shut down for less than 2 hours and has the necessary data stored in memory with the RTC running. In a hot start, the receiver takes 1 second to acquire its position. The time to calculate a ﬁx in this state is sometimes referred to as Time to Subsequent Fix or TTSF.

The module’s high-performance RF architecture allows it to receive GPS signals that are as low as –160dBm. The F4 Series can track up to 48 satellites at the same time. Once locked onto the visible satellites, the receiver calculates the range to the satellites and determines its position and the precise time. It then outputs the data through a standard serial port using several standard NMEA protocol formats.

The GPS core handles all of the necessary initialization, tracking, and calculations autonomously, so no programming is required. The RF section is optimized for low level signals, and requires no production tuning.

Power Supply Requirements

The module requires a clean, well-regulated power source. While it is preferable to power the unit from a battery, it can operate from a power supply as long as noise is less than 20mV. Power supply noise can signiﬁcantly affect the receiver’s sensitivity, therefore providing clean power to the module should be a high priority during design. Bypass capacitors should be placed as close as possible to the module. The values should be adjusted depending on the amount and type of noise present on the supply line.

The 1PPS Output

The 1PPS line outputs 1 pulse per second on the rising edge of the GPS second when the receiver has an over-solved navigation solution from ﬁve or more satellites. The pulse has a duration of 200ms with the rising edge on the GPS second. This line is low until the receiver acquires an over-solved navigation solution (a lock on more than 4 satellites). The GPS second is based on the atomic clocks in the GPS satellites, which are monitored and set to Universal Time master clocks. This output and the time calculated from the GPS satellite transmissions can be used as a clock feature in an end product.

– – – –

Page 7

Antenna Considerations

The F4 Series module is designed to utilize a wide variety of external antennas, but care must be taken in antenna selection to ensure optimum performance. For example, a handheld device may be used in many varying orientations so an antenna element with a wide and uniform pattern may yield better overall performance than an antenna element with high gain and a correspondingly narrower beam. Conversely, an antenna mounted in a ﬁxed and predictable manner may beneﬁt from pattern and gain characteristics suited to that application. Evaluating multiple antenna solutions in real-world situations is a good way to rapidly assess which will best meet the needs of your application.

For GPS, the antenna should have good right hand circular polarization characteristics (RHCP) to match the polarization of the GPS signals. Ceramic patches are the most commonly used style of antenna, but there are many different shapes, sizes and styles of antennas available. Regardless of the construction, they will generally be either passive or active types. Passive antennas are simply an antenna tuned to the correct frequency. Active antennas add a Low Noise Ampliﬁer (LNA) after the antenna and before the module to amplify the weak GPS satellite signals.

For active antennas, a 300 ohm ferrite bead can be used to connect the the RFIN line to an external supply for the antenna. This bead prevents the RF from getting into the power supply, but allows the DC voltage onto the RF trace to feed into the antenna. A series capacitor inside the module prevents this DC voltage from affecting the bias on the module’s internal LNA.

acquire and track satellites and obtain satellite data. It then powers off the RF stage and only uses its processor (CPU) to determine a position ﬁx. Once the ﬁx is obtained, the receiver goes into Hibernate mode. After a user-deﬁned period of time, the receiver wakes up to track the satellites for a user-deﬁned period of time, updates its position using the CPU only, and then resumes standby. The initial acquisition time is variable, depending on whether it is a cold start or assisted, but a maximum acquisition time is deﬁnable. This cycling of power is ideal for battery-powered applications since it signiﬁcantly reduces the amount of power consumed by the receiver while still providing similar performance to the full power mode.

Push-to-Fix mode is for applications that require infrequent position reporting. The module stays in Hibernate mode until either the ON_OFF line is triggered or a user-deﬁned time period has expired. The Push-to-Fix Period is set by a serial command and can be between 10 seconds and two hours. An edge on the ON-OFF line triggers an immediate position ﬁx. When the module wakes up it acquires a new position ﬁx and outputs the NMEA messages before going back into Hibernate mode.

Hibernate mode is the lowest power setting. The tracking and processor blocks are powered down, but the RTC is still running and the memory blocks are still powered, enabling a hot start.

The module switches between these states by toggling the ON_OFF line. The ON_OFF line must go high for at least 100ms to trigger the change of state and must remain low for at least 100ms to reset the edge detector.

100ms 100ms

Maintaining a 50 ohm path between the module and antenna is critical. Errors in layout can signiﬁcantly impact the module’s performance. Please review the layout guidelines elsewhere in this guide carefully to become more familiar with these considerations.

Power Control

The F4 Series GPS Receiver module offers four power control modes: Full Power, Adaptive Trickle Power, Push-to-Fix and Hibernate. In Full Power mode the module is fully active and and continuously tracking. Measurements are of the highest quality and are continuously output by the module. This is the highest current consumption state.

In Adaptive Trickle Power mode, the receiver powers on at full power to

– – – –

ON_OFF

Module Power

Figure 7: F4 Series GPS Receiver Power Control

Full PowerHibernate Full Power

If the module is in Full Power mode, a pulse on the ON_OFF line initiates an orderly shutdown into Hibernate mode. If the module is in Hibernate mode, a pulse transistions the module into Full Power Mode. If the module is in Push-to-ﬁx mode a pulse initiates a single push-to-ﬁx cycle. If the module is in Adaptive Trickle Power mode, a pulse initiates one Trickle Power cycle.

Page 8

Module Power-up Sequence

The module requires a speciﬁc sequence to power up and begin normal operation. When power is ﬁrst applied the module enters a “ready-to-start” state while the Real Time Clock (RTC) starts up and settles. It awaits a pulse on the ON_OFF line to enter Full Power Mode.

The RTC start time is variable, so the host needs to either monitor the RFPWRUP line for a high pulse or wait for at least one second before pulsing the ON_OFF line. An example ﬂowchart is shown in Figure 8.

Start

Module Power-down Sequence

The module requires a controlled power-down sequence. Uncontrolled removal of power while the module is operating carries the risk of data corruption. The consequences of this corruption range from longer TTFF to complete system failure. The appropriate procedure to remove power is shown in Figure 9.

Start

Power on the

module

Wait for ≥1 second

Pull ON_OFF high

for ≥100ms

second timer

expired?

Data output

from the

module?

Send System turn off message to the module (117)

Wait for ≥1 second

for the module to

enter Hibernate

Mode

Remove power

from the module

Yes

End

Figure 9: F4 Series GPS Receiver Power Power-down Sequence

Pull ON_OFF high

for ≥100ms when

the module is in

Full Power Mode

The module is in

Full Power Mode

End

Figure 8: F4 Series GPS Receiver Power Power-up Sequence

– – – –

Page 9

Slow Start Time

The most critical factors in start time are current ephemeris data, signal strength and sky view. The ephemeris data describes the path of each satellite as they orbit the earth. This is used to calculate the position of a satellite at a particular time. This data is only usable for a short period of time, so if it has been more than a few hours since the last ﬁx or if the location has signiﬁcantly changed (a few hundred miles), then the receiver may need to wait for a new ephemeris transmission before a position can be calculated. The GPS satellites transmit the ephemeris data every 30 seconds. Transmissions with a low signal strength may not be received correctly or be corrupted by ambient noise. The view of the sky is important because the more satellites the receiver can see, the faster the ﬁx and the more accurate the position will be when the ﬁx is obtained.

If the receiver is in a very poor location, such as inside a building, urban canyon, or dense foliage, then the time to ﬁrst ﬁx can be slowed. In very poor locations with poor signal strength and a limited view of the sky with outdated ephemeris data, this could be on the order of several minutes. In the worst cases, the receiver may need to receive almanac data, which describes the health and course data for every satellite in the constellation. This data is transmitted every 15 minutes. If a lock is taking a long time, try to ﬁnd a location with a better view of the sky and fewer obstructions. Once locked, it is easier for the receiver to maintain the position ﬁx.

Interfacing with NMEA Messages

Linx modules default to the NMEA protocol. Output messages are sent from the receiver on the TX pin and input messages are sent to the receiver on the RX pin. By default, output messages are sent once every second. Details of each message are described in the following sections.

The NMEA message format is as follows: <Message-ID + Data Payload + Checksum + End Sequence>. The serial data structure defaults to 9,600bps, 8 data bits, 1 start bit, 2 stop bits, and no parity. Each message starts with a $ character and ends with a <CR> <LF>. All ﬁelds within each message are separated by a comma. The checksum follows the * character and is the last two characters, not including the <CR> <LF>. It consists of two hex digits representing the exclusive OR (XOR) of all characters between, but not including, the $ and * characters. When reading NMEA output messages, if a ﬁeld has no value assigned to it, the comma will still be placed following the previous comma. For example, {,04,,,,,2.0,} shows four empty ﬁelds between values 04 and 2.0. When writing NMEA input messages, all ﬁelds are required, none are optional. An empty ﬁeld will invalidate the message and it will be ignored.

Reading NMEA output messages:

• Initialize a serial interface to match the serial data structure of the GPS receiver.

Protocols

Linx GPS modules use the SiRFstar IV chipset. This chipset allows two protocols to be used, NMEA-0183 and SiRF Binary. Switching between the two is handled using a single serial command. The NMEA protocol uses ASCII characters for the input and output messages and provides the most common features of GPS development in a small command set. The SiRF Binary protocol uses BYTE data types and allows more detailed control over the GPS receiver and its functionality using a much larger command set. Although both protocols have selectable baud rates, it’s recommended that SiRF Binary use 115,200bps. For a detailed description of the SiRF Binary protocol, see the SiRF Binary Protocol Reference Manual, available from SiRF Technology, Inc.

Note: Although SiRF Binary protocol may be used with the module,

Linx only offers tech support for the NMEA protocol.

– – – –

• Read the NMEA data from the TX pin into a receive buffer.

• Separate it into six buffers, one for each message type. Use the

characters ($) and <CR> <LF> as end points for each message.

• For each message, calculate the checksum as mentioned above to compare with the received checksum.

• Parse the data from each message using commas as ﬁeld separators.

• Update the application with the parsed ﬁeld values.

• Clear the receive buffer and be ready for the next set of messages.

Writing NMEA input messages:

• Initialize a serial interface to match the serial data structure of the GPS receiver.

• Assemble the message to be sent with the calculated checksum.

• Transmit the message to the receiver on the RX pin.

Page 10

NMEA Output Messages

The following sections outline the data structures of the NMEA messages that are supported by the module. By default, the NMEA commands are output at 9,600bps, 8 data bits, no parity 1 start bit and 2 stop bits.

GGA – Global Positioning System Fixed Data

Figure 10 contains the values for the following example:

$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64

Global Positioning System Fixed Data Example

Name Example Units Description

Message ID $GPGGA GGA protocol header

UTC Time 053740.000 hhmmss.sss

Latitude 2503.6319 ddmm.mmmm

N/S Indicator N N=north or S=south

Longitude 12136.0099 dddmm.mmmm

E/W Indicator E E=east or W=west

Position Fix Indicator 1 See Figure 11

Satellites Used 08 Range 0 to 12.

HDOP 1.1 Horizontal Dilution of Precision

MSL Altitude 63.8 meters

Units M meters

Geoid Separation 15.2 meters

Units M meters

Age of Diff. Corr. second Null ﬁelds when DGPS is not used

Diff. Ref. Station 0000

Checksum *64

<CR> <LF> End of message termination

Figure 10: Global Positioning System Fixed Data Example

Position Indicator Values

Value Description

0 Fix not available or invalid

1 GPS SPS Mode, ﬁx valid

2 Differential GPS, SPS Mode, ﬁx valid

3–5 Not supported

6 Dead Reckoning Mode, ﬁx valid

GLL – Geographic Position – Latitude / Longitude

Figure 12 contains the values for the following example:

$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52

Geographic Position – Latitude / Longitude Example

Name Example Units Description

Message ID $GPGLL GLL protocol header

Latitude 2503.6319 ddmm.mmmm

N/S Indicator N N=north or S=south

Longitude 12136.0099 dddmm.mmmm

E/W Indicator E E=east or W=west

UTC Time 053740.000 hhmmss.sss

Status A A=data valid or V=data not valid

Mode A

Checksum *52

<CR> <LF> End of message termination

Figure 12: Geographic Position – Latitude / Longitude Example

A=autonomous, D=DGPS, N=Data not valid

GSA – GPS DOP and Active Satellites

Figure 13 contains the values for the following example:

$GPGSA,A,3,24,07,17,11,28,08,20,04,,,,,2.0,1.1,1.7*35

GPS DOP and Active Satellites Example

Name Example Units Description

Message ID $GPGSA GSA protocol header

Mode 1 A See Figure 14

Mode 2 3 1=No ﬁx, 2=2D, 3=3D

ID of satellite used 24 Sv on Channel 1

ID of satellite used 07 Sv on Channel 2

... ...

ID of satellite used Sv on Channel 12

PDOP 2.0 Position Dilution of Precision

HDOP 1.1 Horizontal Dilution of Precision

VDOP 1.7 Vertical Dilution of Precision

Checksum *35

<CR> <LF> End of message termination

Figure 11: Position Indicator Values

Figure 13: GPS DOP and Active Satellites Exampl

– – – –

Page 11

Mode 1 Values

Value Description

M Manual – forced to operate in 2D or 3D mode

A Automatic – allowed to automatically switch 2D/3D

Figure 14: Mode 1 Values

GSV – GPS Satellites in View

Figure 15 contains the values for the following example:

$GPGSV,3,1,12,28,81,285,42,24,67,302,46,31,54,354,,20,51,077,46*73

$GPGSV,3,2,12,17,41,328,45,07,32,315,45,04,31,250,40,11,25,046,41*75

$GPGSV,3,3,12,08,22,214,38,27,08,190,16,19,05,092,33,23,04,127,*7B

GPS Satellites in View Example

Name Example Units Description

Message ID $GPGSV GSV protocol header

Total number of

messages

Message number

Satellites in view 12

Satellite ID 28 Channel 1 (Range 01 to 196)

Elevation 81 degrees Channel 1 (Range 00 to 90)

Azimuth 285 degrees Channel 1 (Range 000 to 359)

SNR (C/No) 42 dB-Hz

Satellite ID 20 Channel 4 (Range 01 to 32)

Elevation 51 degrees Channel 4 (Range 00 to 90)

Azimuth 077 degrees Channel 4 (Range 00 to 359)

SNR (C/No) 46 dB-Hz

Checksum *73

<CR> <LF> End of message termination

1. Depending on the number of satellites tracked, multiple messages of GSV data may be required.

3 Range 1 to 3

1 Range 1 to 3

Channel 1 (Range 00 to 99, null when not tracking)

Channel 4 (Range 00 to 99, null when not tracking.

RMC – Recommended Minimum Speciﬁc GPS Data

Figure 16 contains the values for the following example:

$GPRMC,053740.000,A,2503.6319,N,12136.0099,E,2.69,79.65,100106,,,A*53

Recommended Minimum Speciﬁc GPS Data Example

Name Example Units Description

Message ID $GPRMC RMC protocol header

UTC Time 053740.000 hhmmss.sss

Status A A=data valid or V=data not valid

Latitude 2503.6319 ddmm.mmmm

N/S Indicator N N=north or S=south

Longitude 12136.0099 dddmm.mmmm

E/W Indicator E E=east or W=west

Speed over ground 2.69 knots TRUE

Course over ground 79.65 degrees

Date 100106 ddmmyy

Magnetic Variation degrees Not available, null ﬁeld

Variation Sense E=east or W=west (not shown)

Mode A

Checksum *53

<CR> <LF> End of message termination

Figure 16: Recommended Minimum Speciﬁc GPS Data Example

A=autonomous, D=DGPS, N= Data not valid

Figure 15: GPS Satellites in View Example

– – – –

Page 12

VTG – Course Over Ground and Ground Speed

Figure 17 contains the values for the following example:

$GPVTG,79.65,T,,M,2.69,N,5.0,K,A*38

Course Over Ground and Ground Speed Example

Name Example Units Description

Message ID $GPVTG VTG protocol header

Course over ground 79.65 degrees Measured heading

Reference T TRUE

Course over ground degrees Measured heading (N/A, null ﬁeld)

Reference M Magnetic

Speed over ground 2.69 knots Measured speed

Units N Knots

Speed over ground 5.0 km/hr Measured speed

Units K Kilometer per hour

Mode A

Checksum *38

<CR> <LF> End of message termination

A=autonomous, D=DGPS, N= Data not valid

NMEA Input Messages

The following outlines the serial commands input into the module for conﬁguration. By default, the commands are input at 9,600bps, 8 data bits, no parity, 1 start bit and 2 stop bits.

Serial Data Structure

Name Example Description

Start Sequence $PSRF

Message ID <MID>

Payload D ATA Message speciﬁc data.

Checksum CKSUM

End Sequence <CR> <LF>

Figure 18: Serial Data Structure

Message Identiﬁer consisting of three numeric characters. Input messages begin at MID 100.

CKSUM is a two-hex character checksum as deﬁned in the NMEA speciﬁcation, NMEA-0183 Standard for Interfacing Marine Electronic Devices. Checksums are required on all input messages.

Each message must be terminated using Carriage Return (CR) Line Feed (LF) (\r\n, 0x0D0A) to cause the receiver to process the input message. They are not printable ASCII characters, so are omitted from the examples.

Figure 17: Course Over Ground and Ground Speed Example

All ﬁelds in all proprietary NMEA messages are required; none are optional. All NMEA messages are comma delimited. Figure 19 outlines the message identiﬁers supported by the module.

Message ID Values

Name MID Description

SetSerialPort 100 Set serial port parameters and protocol

NavigationInitialization 101 Reset the modules

Query/Rate Control 103

LLANavigationInitialization 104 Reset the modules

Development Data On/Off 105 Development Data messages On/Off

System Turn Off 117

PowerManagement 200 Sets the power performance of the receiver

FirmwareVersion 201 Query the ﬁrmware version

StaticNavigation 202 Sets static navigation On/Off

SetIO 211 Sets the I/O lines to an input or output

ReadInput 212 Reads the state of the inputs lines

WriteOutput 213 Writes the state of an output line

Query standard NMEA message and/or set output rate

Performs an orderly shut down of the module and switches into hibernation mode

– – – –

Page 13

Query 214 Get conﬁguration and last state of all GPIOs

Query 215

Figure 19: Message ID Values

Get conﬁguration and current state of all GPIOs

100 – SetSerialPort

This command message is used to set the protocol (SiRF binary or NMEA) and/or the communication parameters (baud rate). Generally, this command is used to switch the module back to SiRF binary protocol mode where a more extensive command message set is available. When a valid message is received, the parameters are stored in battery-backed SRAM and the receiver restarts using the saved parameters.

Figure 20 contains the values for the following example: Switch to SiRF binary protocol at 9600,8,N,1

$PSRF100,0,9600,8,1,0*0C

SetSerialPort Example

Name Example Description

Message ID $PSRF100 PSRF100 protocol header

Protocol 0 0=SiRF binary, 1=NMEA

Baud 9600 4800, 9600, 19200, 38400, 57600, 115200

DataBits 8 8

StopBits 1 0, 1

Parity 0 0=None, 1=Odd, 2=Even

Checksum *0C

<CR> <LF> End of message termination

1. SiRF protocol is only valid for 8 data bits, 1 stop bit and no parity.

2. Default settings are NMEA protocol using 9,600 baud, 8 data bits, 2 stop bits and no parity.

Figure 20: SetSerialPort Example

For details on the SiRF binary protocol, please refer to SiRF’s Binary Protocol Reference Manual.

101 – NavigationInitialization

This command is used to initialize the receiver with the current position (in X, Y, Z coordinates), clock offset, and time, enabling a faster ﬁx. Increased receiver sensitivity and the removal of Selective Availability (SA) have made this unneccessary. The command is retained for its ability to reset the module, but the initialization ﬁelds are no longer supported.

Figure 21 contains the values for the following example:

$PSRF101,-2686700,-4304200,3851624,96000,497260,921,12,3*1C

NavigationInitialization Example

Name Example Units Description

Message ID $PSRF101 PSRF101 protocol header

ECEF X -2686700 meters X coordinate position

ECEF Y -4304200 meters Y coordinate position

ECEF Z 3851624 meters Z coordinate position

ClkOffset 96000 Hz Clock Offset

TimeOfWeek 497260 seconds GPS Time Of Week

WeekNo 921 GPS Week Number

ChannelCount 12 Range 1 to 12

ResetCfg 3 See Figure 22

Checksum *1F

<CR> <LF> End of message termination

1. Use 0 for the last saved value if available. If this is unavailable, a default value of 96000 is used.

Figure 21: NavigationInitialization Example

ResetCfg Values

Hex Description

0x01 Hot Start – All data valid

0x02 Warm Start – Ephemeris cleared

0x04 Cold Start – Clears all data in memory

0x08

Clear Memory – Clears all data in memory and resets the receiver back to factory defaults

Figure 22: ResetCfg Values

– – – –

Page 14

103 – Update Rate Control

This command is used to control the output of standard NMEA messages GGA, GLL, GSA, GSV, RMC and VTG. Using this command message, standard NMEA messages may be polled once, or setup for periodic output. Checksums may also be enabled or disabled depending on the needs of the receiving program. NMEA message settings are saved in battery-backed memory for each entry when the message is accepted.

Figure 23 contains the values for the following example:

1. Query the GGA message with checksum enabled

$PSRF103,00,01,00,01*25

2. Enable VTG message for a 1Hz constant output with checksum enabled

$PSRF103,05,00,01,01*20

3. Disable VTG message

$PSRF103,05,00,00,01*21

4. Enable 5Hz mode

$PSRF103,0,6,0,0*23

5. Disable 5Hz mode

$PSRF103,0,7,0,0*22

Note: When using 5Hz mode, it is recommended to disable any

unused NMEA message types (see example 3) and set the serial port to maximum baud rate (see Figure 20). The rate divider takes effect only after a ﬁx is established.

Update Rate Control Example

Name Example Units Description

Message ID $PSRF103 PSRF103 protocol header

Msg 00 See Figure 24

Mode 01

Rate

CksumEnable 01 0=Disable, 1=Enable Checksum

Checksum *25

<CR> <LF> End of message termination

1. Default setting is GGA, GLL, GSA, GSV, RMC and VTG NMEA messages are enabled with checksum at a rate of 1 second.

2. Enabling the rate divider divides the rate value by 5.

3. Rate value sets the period of a single transmission. For maximum update rate (5Hz) enter a value of 1 and enable the rate divider.

Figure 23: Update Rate Control Example

MSGValues

Value Description

0 GGA

1 GLL

2 GSA

3 GSV

4 RMC

5 VTG

6 MSS (not supported)

7 Not deﬁned

8 ZDA

9 Not deﬁned

0=SetRate, 1=Query, 6=Enable divider2, 7=Disable divider

00 seconds Output: off=0, max=255

Figure 24: MSG Values

– – – –

Page 15

104 – LLANavigationInitialization

This command is used to initialize the receiver with the current position (in lattitude, longitude and altitude coordinates), clock offset, and time, enabling a faster ﬁx. Increased receiver sensitivity and the removal of Selective Availability (SA) have made this unneccessary. The command is retained for its ability to reset the module, but the initialization ﬁelds are no longer supported.

Figure 25 contains the values for the following example:

$PSRF104,37.3875111,-121.97232,0,96000,237759,1946,12,1*07

LLANavigationInitialization Example

Name Example Units Description

Message ID $PSRF104 PSRF104 protocol header

Latitude 37.3875111 degrees Latitude position (Range 90 to –90)

Longitude

Altitude 0 meters Altitude position

ClkOffset 96000 Hz

TimeOfWeek 237759 seconds GPS Time Of Week

WeekNo 1946

ChannelCount 12 Range 1 to 12

ResetCfg 1 See Figure 26

Checksum *07

<CR> <LF> End of message termination

1. Use 0 for the last saved value if available. If this is unavailable, a default value of 96000 is used.

-121.97232 degrees

Longitude position (Range 180 to –180)

Clock Offset of the Evaluation Receiver1

Extended GPS Week Number (1024 added)

105 – Development Data On / Off

Use this command to enable development data information if you are having trouble getting commands accepted. Invalid commands generate debug information that helps to determine the source of the command rejection. Common reasons for input command rejection are invalid checksum or parameter out of speciﬁed range.

Figure 27 below contains the values for the following example:

1. Debug On

$PSRF105,1*3E

2. Debug Off

$PSRF105,0*3F

Development Data On / Off Example

Name Example Units Description

Message ID $PSRF105 PSRF105 protocol header

Debug 1 0=Off, 1=On

Checksum *3E

<CR> <LF> End of message termination

1. Default setting is debug mode off.

Figure 27: Development Data On / Off Example

117 – System Turn Off

This message requests that the GPS receiver perform an orderly shutdown and switch to hibernate mode.

Figure 28 below contains the values for the following example:

$PSRF117,16*0B

Figure 25: NavigationInitialization Example

ResetCfg Values

Hex Description

0x01 Hot Start – All data valid

0x02 Warm Start – Ephemeris cleared

0x04 Cold Start – Clears all data in memory

0x08

Figure 26: ResetCfg Values

Clear Memory – Clears all data in memory and resets the receiver back to factory defaults

System Turn Off Example

Name Example Units Description

Message ID $PSRF117 PSRF117 protocol header

Sub ID 16 16: System turn off

Checksum *0B

<CR> <LF> End of message termination

Figure 28: System Turn Off Example

– – – –

Page 16

200 – PowerManagement

This command sets the power mode to Full Power, Adaptive Trickle Power, or Push-to-Fix mode. Figure 29 contains the values for the following example to set the receiver to Adaptive Trickle Power mode:

$PLSC,200,2,200,3000,300000,30000*0D

Power Management Command Example

Name Example Units Description

MID $PLSC,200 Message ID

Mode 2 See Figure 30

OnTime

LP Interval

MaxAcqTime

MaxOffTime

PushToFixPeriod (10 – 7200) sec

Checksum *0D

Figure 28: Power Management Command Example

<CR> <LF> End of message termination

1. Default setting is full power; trickle power disabled.

Figure 29: Power Management Command Example

200

(200 – 900)

3000

(1000 – 10000)

300000 (≥1000)

30000

(1000 –

1800000)

Must be a multiple of 100 (if not, it is

rounded up to the nearest multiple of 100). Set this to 0 when Mode = 3.

Must be an integer value ≥1000 and

≤10000. Set this to 0 when Mode = 3.

When Adaptive Trickle Power is enabled, this is the maximum allowable time from the start of a power cycle to the time a valid position ﬁx is obtained. If no ﬁx is obtained

in this time, the receiver is deactivated for up to MaxOffTime, and a hot start is commanded when the receiver reactivates. The integer must be in multiples of 1000ms. There is no upper limit.

The longest period (in mS) for which the receiver deavtivates due to the MaxAcqTime timeout. The actual

deactivated period may be less if the user-speciﬁed duty cycle (OnTime / LpInterval) can be maintained.

The receiver automatically awakens every Push-to-Fix period to obtain a position ﬁx, collect ephemeris (if needed), and calibrate the real-time clock (RTC) (if needed).

The receiver outputs a response to this command. Figure 31 contains the response for the above command:

$PLSR,200,1,2,300,1000,300000,30000*02

Power Management Response Example

Name Example Units Description

MID $PLSC,200 Message ID

Valid 1 0: command invalid, 1:command valid

Mode 2 See Figure 30

OnTime 200 ms Displayed when mode = 2

LP Interval 3000 ms Displayed when mode = 2

MaxAcqTime 300000 ms Displayed when mode = 2 or 3

MaxOffTime 30000 ms Displayed when mode = 2 or 3

PushToFixPeriod sec Displayed when mode = 3

Checksum *01

<CR> <LF> End of message termination

Figure 31: Power Management Response Example

For some further examples of this command:

Query the power management mode Input command: $PLSC,200,0*0E Output response: $PLSR,200,1,1*03

Set the receiver to Full Power mode Input command: $PLSC,200,1*0F Output response: $PLSR,200,1,1*03

Set the receiver to Adaptive Trickle Power mode Input command: $PLSC,200,2,900,10000,300000,30000*34 Output response: $PLSR,200,1,2,900,10000,300000,30000*38

Mode Values

Value Description

0 Ask the receiver to send the current power mode

1 Set the receiver to Full Power mode

2 Set the receiver to Adaptive Trickle Power mode

3 Set the receiver to Push-to-Fix mode

Figure 30: Power Management Mode Values

Set the receiver to Push-to-Fix Power mode Input command: $PLSC,200,3,0,0,300000,30000,7200*14 Output response: $PLSR,200,1,3,300000,30000,7200*18

– – – –

Page 17

201 – Poll Software Version

Figure 32 contains the values for the following example to poll the SiRF and Linx software versions:

$PLSC,201*13

Poll Software Version Command Example

Name Example Units Description

MID $PLSC,201 Message ID

Checksum *0D

<CR> <LF> End of message termination

Figure 32: Poll Software Version Example

202 – StaticNavigation

This command is used to query, enable, and disable static navigation. Figure 34 contains the values for the following example to disable static navigation:

$PLSC,202,2*0E

StaticNavigation Example

Name Example Units Description

MID $PLSR,202 Message ID

Command 2 0: Query, 1: Enable (default), 2: Disable

Checksum *0E

<CR> <LF> End of message termination

Figure 33 contains the response for this command:

$PLSR,201,1,GSD4e_4.1.2,B20121219.9600BPS.CUSTOMIO.LINX*58

Poll Software Version Response Example

Name Example Units Description

MID $PLSC,201 Message ID

Valid 1 0: command invalid, 1:command valid

SiRF String SiRF software version

Linx String Linx software version

Checksum *01

<CR> <LF> End of message termination

Figure 33: Power Management Response Example

Figure 34: StaticNavigation Example

Figure 35 contains the response for the above command.

StaticNavigation Response Example

Name Example Units Description

MID $PLSR,202 Message ID

Valid 1 0: command invalid; 1: command valid

Result 2

Checksum *02

<CR> <LF> End of message termination

Figure 35: StaticNavigation Response Example

0: command failed; 1: static navigation enabled, 2: static navigation disabled

– – – –

Page 18

211 – SetIO

Figure 36 contains the values for the following example to get GPIOA as an input:

$PLSC,211,A,0,0*7F

212 – ReadInput

Figure 38 contains the values for the following example to read the state of an input:

$PLSC,212,A*7C

SetIO Example

Name Example Units Description

MID $PLSC,211 Message ID

GPIO Number A

Direction 0 Direction: 0 = Input; 1 = Output

State 0

Checksum *7F

<CR> <LF> End of message termination

Figure 36: SetIO Example

Number of the GPIO line to set. Only one line can be set at a time.

Set to 1 if the direction is an output; the value does not matter if the direction is an input.

The receiver outputs a response to this command. Figure 37 contains the response for the above command.

SetIO Response Example

Name Example Units Description

MID $PLSR,211 Message ID

Valid 1 0: command invalid, 1: command valid

Checksum *7F

<CR> <LF> End of message termination

ReadInput Example

Name Example Units Description

MID $PLSC,212 Message ID

GPIO Number A

Checksum *7C

<CR> <LF> End of message termination

Figure 38: ReadInput Example

Number of the GPIO line to set. Only one line can be set at a time.

The receiver outputs a response to this command. Figure 39 contains the response for the above command.

ReadInput Response Example

Name Example Units Description

MID $PLSR,212 Message ID

GPIO Number A

State 0

Checksum *71

<CR> <LF> End of message termination

Number of the GPIO line to set. Only one line can be set at a time.

0 = Low; 1 = High; 2 = the referenced GPIO is not an input

Figure 37: SetIO Response Example

For some further examples of this command:

Set GPIOA as an input Input command: $PLSC,211,A,0,0*7F Output response: $PLSR,211,1*1E

Set GPIOA as an output, initial state low Input command: $PLSC,211,A,1,0*7F Output response: $PLSR,211,1*1E

NOTE

1. If the message ID is not recognized, the response will be “$PLSR,999,0,ERROR*60”

2. If the value is not allowed, the response will be “$PLSR,MID,0,ERROR*CS”

3. All GPIOs default to inputs on power-up and reset

– – – –

Figure 39: ReadInput Response Example

For some further examples of this command:

Read that GPIOA is low Input command: $PLSC,212,A*7C Output response: $PLSR,212,A,0*71

Read that GPIOA is high Input command: $PLSC,212,A*7C Output response: $PLSR,212,A,1*70

Read that GPIOA is not an input Input command: $PLSC,212,A*7C Output response: $PLSR,212,A,2*73

Page 19

213 – WriteOutput

Figure 40 contains the values for the following example to write the state of GPIOA to low:

$PLSC,213,A,0*61

214 – Query: Get Conﬁguration and GPIO Last State

Figure 42 contains the values for the following example to read the conﬁguration and state of all of the GPIO lines:

$PLSC,214*17

WriteOutput Example

Name Example Units Description

MID $PLSC,213 Message ID

GPIO Number A

State 0 State; 0 = Low; 1 = High

Checksum *61

<CR> <LF> End of message termination

Figure 40: WriteOutput Example

Number of the GPIO line to write. Only one line can be set at a time.

The receiver outputs a response to this command. Figure 41 contains the response for the above command.

WriteOutput Response Example

Name Example Units Description

MID $PLSR,213 Message ID

Valid A 0: command invalid, 1: command valid

Checksum *1C

<CR> <LF> End of message termination

Figure 41: WriteOutput Response Example

For some further examples of this command:

Set GPIOA to low Input command: $PLSC,213,A,0*61 Output response: $PLSR,213,1*1C

Set GPIOA to high Input command: $PLSC,213,A,1*60 Output response: $PLSR,213,1*1C

GPIOA is not an output Input command: $PLSC,213,A,1*60 Output response: $PLSR,213,0*1D

Query Example

Name Example Units Description

MID $PLSC,214 Message ID

Checksum *17

<CR> <LF> End of message termination

Figure 42: Query Example

The receiver outputs a response to this command. Figure 43 contains the response for the above command.

WriteOutput Example

Name Example Units Description

MID $PLSR,214 Message ID

Count 5 Total number of GPIOs

GPIO Number A GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number B GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number C GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number D GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 1 0 = Low; 1 = High

GPIO Number E GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

Checksum *73

<CR> <LF> End of message termination

Figure 43: Query Response Example

– – – –

Page 20

215 – Query: Get Conﬁguration and GPIO Current State

Figure 44 below contains the values for the following example to read the conﬁguration and state of all of the GPIO lines:

$PLSC,215*16

Query Example

Name Example Units Description

MID $PLSC,215 Message ID

Checksum *16

<CR> <LF> End of message termination

Figure 44: Query Example

The receiver outputs a response to this command. Figure 45 contains the response for the above command.

WriteOutput Example

Name Example Units Description

MID $PLSR,215 Message ID

Count 5 Total number of GPIOs

GPIO Number A GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number B GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number C GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

GPIO Number D GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 1 0 = Low; 1 = High

GPIO Number E GPIO Number

Conﬁguration 0 Direction; 0 = Input; 1 = Output

Current State 0 0 = Low; 1 = High

Checksum *72

<CR> <LF> End of message termination

For some further examples of this command:

Set GPIO 1 to low Input command: $PLSC,215*16 Output response: $PLSR,215,5,1,0,0,10,0,1,13,0,1,14,0,1,15,0,1*00

Figure 45: Query Response Example

– – – –

Page 21

Typical Applications

Figure 46 shows the R4 Series GPS receiver in a typical application using a passive antenna.

VCC

µP

GND

VCC

RX TX

OUT

GPIOD

GPIOE

3 4 5 21

6 7 8 9 10

1PPS TX RX GND

GPIOC P1 /RESET RFPWRUP ON_OFF

GPIOB GPIOA

Level

Shifter

GND

1.8V

2.2k

GND RFIN GND

NC NC

GND

VCC

20 19 18 17 16 22

15 14 13 12 11

GND

100k

2.2k

GND

1.8V

Master Development System

The F4 Series Master Development System provides all of the tools necessary to evaluate the F4 Series GPS receiver module. The system includes a fully assembled development board, an active antenna, development software and full documentation.

Figure 48: The F4 Series Master Development System

Figure 46: Circuit Using the F4 Series Module with a Passive Antenna

A microcontroller UART is connected to the receiver’s UART for passing data and commands. A 3.3V coin cell battery is connected to the VBACKUP line to provide power to the module’s memory when main power is turned off.

Figure 47 shows the module using an active antenna.

VCC

µP

GND

VCC

OUT

GPIOD

GPIOE

3 4 5 21

6 7 8 9 10

1PPS TX RX GND

GPIOC P1 /RESET RFPWRUP ON_OFF

GPIOB GPIOA

Level

Shifter

GND

1.8V

2.2k

GND

RFIN

GND

NC NC

GND

VCC

20 19 18 17 16 22

15 14 13 12 11

GND

100k

2.2k

300Ω

Ferrite Bead

18pF

GND

1.8V

VCC

Figure 47: Circuit Using the F4 Series Module with a an Active Antenna

A 300Ω ferrite bead is used to put power from VOUT onto the antenna line to power the active antenna.

The development board includes a power supply, a prototyping area for custom circuit development, and an OLED display that shows the GPS data without the need for a computer. A USB interface is also included for use with a PC running custom software or the included development software.

Figure 49: The F4 Series Master Development System Software

The Master Development System software enables conﬁguration of the receiver and displays the satellite data output by the receiver. The software can select from among all of the supported NMEA protocols for display of the data.

Full documentation for the board and software is included in the development system, making integration of the module straightforward.

– – – –

Page 22

Board Layout Guidelines

The module’s design makes integration straightforward; however, it is still critical to exercise care in PCB layout. Failure to observe good layout techniques can result in a signiﬁcant degradation of the module’s performance. A primary layout goal is to maintain a characteristic 50-ohm impedance throughout the path from the antenna to the module. Grounding, ﬁltering, decoupling, routing and PCB stack-up are also important considerations for any RF design. The following section provides some basic design guidelines which may be helpful.

During prototyping, the module should be soldered to a properly laid-out circuit board. The use of prototyping or “perf” boards will result in poor performance and is strongly discouraged.

The module should, as much as reasonably possible, be isolated from other components on your PCB, especially high-frequency circuitry such as crystal oscillators, switching power supplies, and high-speed bus lines.

Each of the module’s ground pins should have short traces tying immediately to the ground plane through a via.

Bypass caps should be low ESR ceramic types and located directly adjacent to the pin they are serving.

A 50-ohm coax should be used for connection to an external antenna. A 50-ohm transmission line, such as a microstrip, stripline or coplanar waveguide should be used for routing RF on the PCB. The Microstrip Details section provides additional information.

In some instances, a designer may wish to encapsulate or “pot” the product. There is a wide variety of potting compounds with varying dielectric properties. Since such compounds can considerably impact RF performance and the ability to rework or service the product, it is the responsibility of the designer to evaluate and qualify the impact and suitability of such materials.

When possible, separate RF and digital circuits into different PCB regions. Make sure internal wiring is routed away from the module and antenna, and is secured to prevent displacement.

Do not route PCB traces directly under the module. There should not be any copper or traces under the module on the same layer as the module, just bare PCB. The underside of the module has traces and vias that could short or couple to traces on the product’s circuit board.

The Pad Layout section shows a typical PCB footprint for the module. A ground plane (as large and uninterrupted as possible) should be placed on a lower layer of your PC board opposite the module. This plane is essential for creating a low impedance return for ground and consistent stripline performance.

Use care in routing the RF trace between the module and the antenna or connector. Keep the trace as short as possible. Do not pass under the module or any other component. Do not route the antenna trace on multiple PCB layers as vias will add inductance. Vias are acceptable for tying together ground layers and component grounds and should be used in multiples.

Pad Layout

The pad layout diagram in Figure 50 is designed to facilitate both hand and automated assembly.

0.036 (0.92)

0.045 (1.15)

0.512

(13.00)

0.050 (1.27)

Figure 50: Recommended PCB Layout

0.036 (0.92)

0.020 (0.50)

0.028

(0.70)

0.050 (1.27)

– – – –

Page 23

Microstrip Details

A transmission line is a medium whereby RF energy is transferred from one place to another with minimal loss. This is a critical factor, especially in high-frequency products like Linx RF modules, because the trace leading to the module’s antenna can effectively contribute to the length of the antenna, changing its resonant bandwidth. In order to minimize loss and detuning, some form of transmission line between the antenna and the module should be used, unless the antenna can be placed very close (<1⁄8in) to the module. One common form of transmission line is a coax cable; another is the microstrip. This term refers to a PCB trace running over a ground plane that is designed to serve as a transmission line between the module and the antenna. The width is based on the desired characteristic impedance of the line, the thickness of the PCB, and the dielectric constant of the board material. For standard 0.062" thick FR-4 board material, the trace width would be 111 mils. The correct trace width can be calculated for other widths and materials using the information below. Handy software for calculating microstrip lines is also available on the Linx website, www.linxtechnologies.com.

Trace

Board

Ground plane

Production Guidelines

The module is housed in a hybrid SMD package that supports hand and automated assembly techniques. Since the modules contain discrete components internally, the assembly procedures are critical to ensuring the reliable function of the modules. The following procedures should be reviewed with and practiced by all assembly personnel.

Hand Assembly

Pads located on the bottom of the module are the primary mounting surface (Figure 53). Since these pads are inaccessible during mounting, castellations that run up the side of the module have been provided to facilitate solder wicking to the module’s underside. This allows for very quick hand soldering for prototyping and small volume production. If the recommended pad guidelines have been followed, the pads will protrude slightly past the edge of the module. Use a ﬁne soldering tip to heat the board pad and the castellation, then introduce solder to the pad at the module’s edge. The solder will wick underneath the module, providing reliable attachment. Tack one module corner ﬁrst and then work around the device, taking care not to exceed the times in Figure 54.

Soldering Iron Tip

Solder

PCB Pads

Figure 53: Soldering Technique

Castellations

Figure 51: Microstrip Formulas

Example Microstrip Calculations

Dielectric Constant

4.80 1.8 3.59 50.0

4.00 2.0 3.07 51.0

2.55 3.0 2.12 48.0

Figure 52: Example Microstrip Calculations

Width/Height

Ratio (W/d)

Warning: Pay attention to the absolute maximum solder times.

Absolute Maximum Solder Times

Hand Solder Temperature: +427ºC for 10 seconds for lead-free alloys

Reﬂow Oven: +240°C max (see Figure 55)

Figure 54: Absolute Maximum Solder Times

Automated Assembly

Effective Dielectric

Constant

– – – –

Characteristic

Impedance (Ω)

For high-volume assembly, the modules are generally auto-placed. The modules have been designed to maintain compatibility with reﬂow processing techniques; however, due to their hybrid nature, certain aspects of the assembly process are far more critical than for other component types. Following are brief discussions of the three primary areas where

caution must be observed.

Page 24

Reﬂow Temperature Proﬁle

The single most critical stage in the automated assembly process is the reﬂow stage. The reﬂow proﬁle in Figure 55 should not be exceeded because excessive temperatures or transport times during reﬂow will irreparably damage the modules. Assembly personnel need to pay careful attention to the oven’s proﬁle to ensure that it meets the requirements necessary to successfully reﬂow all components while still remaining within the limits mandated by the modules. The ﬁgure below shows the recommended reﬂow oven proﬁle for the modules.

Peak: 240+0/-5°C

220°C

Preheat:

150 - 200°C

2 - 3°C/sec

25 - 35sec

Resources

Support

For technical support, product documentation, application notes, regulatory guidelines and software updates, visit www.linxtechnologies.com

RF Design Services

For customers who need help implementing Linx modules, Linx offers design services including board layout assistance, programming, certiﬁcation advice and packaging design. For more complex RF solutions, Apex Wireless, a division of Linx Technologies, creates optimized designs with RF components and ﬁrmware selected for the customer’s application. Call +1 800 736 6677 (+1 541 471 6256 if outside the United States) for more information.

120 - 150sec

2 - 4°C/sec

30°C

Figure 55: Maximum Reﬂow Proﬁle

60 - 80sec

Shock During Reﬂow Transport

Since some internal module components may reﬂow along with the components placed on the board being assembled, it is imperative that the modules not be subjected to shock or vibration during the time solder is liquid. Should a shock be applied, some internal components could be lifted from their pads, causing the module to not function properly.

Washability

The modules are wash-resistant, but are not hermetically sealed. Linx recommends wash-free manufacturing; however, the modules can be subjected to a wash cycle provided that a drying time is allowed prior to applying electrical power to the modules. The drying time should be sufﬁcient to allow any moisture that may have migrated into the module to evaporate, thus eliminating the potential for shorting damage during power-up or testing. If the wash contains contaminants, the performance may be adversely affected, even after drying.

Antenna Factor Antennas

Linx’s Antenna Factor division has the industry’s broadest selection of antennas for a wide variety of applications. For

customers with specialized needs, custom antennas and design services are available along with simulations of antenna performance to speed development. Learn more at www.linxtechnologies.com.

– – – –

Page 25

Linx Technologies

159 Ort Lane

Merlin, OR, US 97532

Phone: +1 541 471 6256

Fax: +1 541 471 6251

www.linxtechnologies.com

Disclaimer

Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we reserve the right to make changes to our products without notice. The information contained in this Data Guide is believed to be accurate as of the time of publication. Speciﬁcations are based on representative lot samples. Values may vary from lot-to-lot and are not guaranteed. “Typical” parameters can and do vary over lots and application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any product for use in any speciﬁc application. It is the customer’s responsibility to verify the suitability of the part for the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY APPLICATION WHERE THE SAFETY

OF LIFE OR PROPERTY IS AT RISK.

Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF CUSTOMER’S INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE OR NON-CONFORMING PRODUCTS OR FOR ANY OTHER BREACH OF CONTRACT BY LINX TECHNOLOGIES. The limitations on Linx Technologies’

liability are applicable to any and all claims or theories of recovery asserted by Customer, including, without limitation, breach of contract, breach of warranty, strict liability, or negligence. Customer assumes all liability (including, without limitation, liability for injury to person or property, economic loss, or business interruption) for all claims, including claims from third parties, arising from the use of the Products. The Customer will indemnify, defend, protect, and hold harmless Linx Technologies and its ofﬁcers, employees, subsidiaries, afﬁliates, distributors, and representatives from and against all claims, damages, actions, suits, proceedings, demands, assessments, adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any Products sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for losses arising from the use or failure of the device in any application, other than the repair, replacement, or refund limited to the original product purchase price. Devices described in this publication may contain proprietary, patented, or copyrighted techniques, components, or materials. Under no circumstances shall any user be conveyed any license or right to the use or ownership of such items.

The stylized Linx logo, Wireless Made Simple, WiSE, CipherLinx and the stylized CL logo are trademarks of Linx Technologies.