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compatibility between GlobalTop u5 series and u-blox LEA series

Started by Horsa, June 10, 2011, 12:56:36 PM

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Q: is GlobalTop u5 series pin and function compatible with u-blox LEA series?


GlobalTop u5 series maintain the industry standard 17.0 x 22.4 mm form factor of the LEA-6, LEA-5 and LEA-4 series and have been designed to allow simple migration.
Due to inherited differences between MediaTek and u-blox chips, there will be differences between GlobalTop u5 series and numerous LEA modules. The good thing is that most LEA modules are pin-compatible across different generations and in between series for some of the basic GPS functions (NMEA output), but differs in additional support functions such as the inclusion of TCXO (temperature controlled crystal oscillator), Flash, Galileo support, antenna status report and port types.

Main compatibilities:

A. Basic GPS function is compatible: This means that if the application refers solely to the basic GPS function (NMEA output), there will be no differences between u5 and LEA series.

B. If a pin is defined in both u5 and LEA series in the same way, it should function the same way as well; see for instance 1PPS and USB.

C. solder mask: u5 series footprint is compatible with the LEA series solder mask; please consult the corresponding u-blox hardware integration manual.

Main differences:

a. Watch out for electrical characteristics: LEA series support 2.7.V to 3.6 V, while u5 series only supports a slightly narrower range of 3.0 v to 3.6 v

b. Antenna Status Detection (Antenna advisor vs. Antenna Supervisor) is different in both hardware layout and software report protocol. Users will have to redesign this part. User wishing to implement antenna status detection shall double check GlobalTop data sheet.

c. No DDC port, no Wake-up pin, No SPI port in GlobalTop u5 series

d. Since GlobalTop u5 series is based on the MediaTek 3329 chip, the software aspect other than the basic NMEA (things such as packet command, power saving mode, AGPS, and other customizable features) will function differently.

e. GlobalTop u5 series has the following features not found in any of the LEA series:

  • FW flash update (only available in H type of LEA series)
  • TCXO (only available in H, Q, S and T type of LEA series)
  • Antenna Status Report (only available in "A, H, S and T type of LEA series)

f. GlobalTop u5 has no dead reckoning compatibility, no precision timing, and no raw data output, and is not compatible with GALILEO

If you have special questions on usage and compatibility with a particular LEA model, please feel free post you inquiry on the correspondingforum board.

LEA-4 Family



LEA-5 Family




LEA-6 Family



GlobalTop u5 series: Gmm-u5LP, Gmm-u5j, Gms-u5LP.