u-blox EVA-8M Series Hardware Integration Manual

Contents

u-blox EVA-8M Series Hardware Integration Manual Manual pdf 20 page image

EVA-8M and EVA-M8 series - Hardware Integration ManualUBX-16010593 - R06 Design-in Page 20 of 47Early Production Information31 TIMEPULSE O Time pulse output Leave open if not used.32 D_SEL I Interface selector See section 2.2.33 SAFEBOOT_N I Used for programming the SQI flashmemory and testing purposes.Leave open if not used.34 ANT_OK I Antenna status Leave open if not used.35 ANT_OFF O Antenna control Leave open if not used.36 Reserved I/O Reserved Do not connect. Must be left open!37 GND I Ground Inner ground pin38 GND I Ground Inner ground pin39 GND I Ground Inner ground pin40 GND I Ground Inner ground pin41 GND I Ground Inner ground pin42 GND I Ground Inner ground pin43 GND I Ground Inner ground pinTable 5: EVA-8M / EVA-M8 series GNSS modules pin description2.9.1 Pin name changesSelected EVA-M8M pin names have been updated to agree with a common naming convention acrossu-blox modules. The pins have not changed their operation and are the same physical hardware butwith updated names. The table below lists those pins along with their old and new names.No Previous Name New name7 V_USB VDD_USB15 RX / MOSI RXD / SPI MOSI16 TX / MISO TXD / SPI MISO26 SQI_CS SQI_CS_N29 SCL / SCK SCL / SPI CLK30 SDA / CS_N SDA / SPI CS_NTable 6: EVA-M8M pin name changes☞ For more information about pin assignment see theEVA-M8 Data Sheet [1] and theEVA-8M DataSheet [2]2.10 Layout design-in checklistFollow this checklist for the layout design to get an optimal GNSS performance.Layout optimizations (Section 2.11) Is the EVA-8M / EVA-M8 module placed according to the recommendation in section 2.11.3? Is the grounding concept optimal? Has the 50 Ω line from antenna to module (micro strip / coplanar waveguide) been kept as shortas possible? Assure low serial resistance in VCC power supply line (choose a line width > 400 um). Keep power supply line as short as possible. Design a GND guard ring around the optional RTC crystal lines and GND below the RTC circuit. Add a ground plane underneath the GNSS module to reduce interference. This is especiallyimportant for the RF input line. For improved shielding, add as many vias as possible around the micro strip/coplanar waveguide,around the serial communication lines, underneath the GNSS module, etc.