LimeNET-Micro v2.1 hardware description

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LimeNET-Micro Board Key Features

LimeNET Micro makes deploying wireless networks more accessible than ever before, by extending the LimeNET line of integrated hardware solutions via an ultra-low cost platform that is capable of supporting narrowband systems, such as GSM and IoT wireless standards, in a stand-alone configuration.

File:TBD.png
Figure 1. LimeSDR-Micro v2.1


LimeNET-Micro board features:

  • RF transceiver
    • Lime Microsystems LMS7002M
  • Raspberry Pi
    • DDR2 SODIMM socket for raspberry Pi CM3(L)
    • 2x downstream USB 2.0 ports
    • Upstream Micro-USB for USB boot of Compute Module
    • 3.5mm analog audio, composite video output
    • Ethernet + active PoE (RJ45) connector
    • Ribbon cable camera and display connectors
    • HDMI connector
    • External UART connector
    • uSD card slot
    • USB2.0 HUB and 10/100 Ethernet controller
    • SDIO Wi-Fi module
    • Jumper for Raspberry boot mode selection
  • FPGA Features
    • Intel MAX10 10M16SAU169C8 device in 169-pin UBGA
    • 16K logic elements
    • 549 Kbits embedded memory (M9K) and 2368 Kbits of user Flash Memory
    • 45 embedded 18x18 multipliers
    • 1 PLLs
  • FPGA Configuration
    • JTAG mode configuration
  • USB Controller
    • FTDI FT601 USB to FIFO interface bridge chip (connects FPGA to USB2.0 HUB)
  • Memory Devices
    • 4Mbit FLASH (for FPGA data)
    • 2x 128Kbit (16K x 8) EEPROM (for LMS MCU firmware and FPGA data)
  • Other Devices
    • Temperature sensor
    • Crypto Authentication Device
    • GNSS receiver
  • Connections
    • 2 x coaxial RF (SMA) connectors
    • SMA connectors for reference clock IN/OUT, GNSS and Wi-Fi antennas
    • 5V DC power jack
    • 5V header for powering external devices
    • Fan header
    • FPGA JTAG connectors (0.05” pitch and side connector)
    • Backup battery connector for GNSS receiver
  • Clock System
    • 30.72MHz VCOCXO:
      • Frequency calibration ±0.5ppm;
      • Frequency stability over temperature in still air ±20ppb;
      • Frequency slope ΔF/ΔT in still air ±1.2ppb/°C
    • Possibility to tune VCOCXO by onboard DAC
    • Possibility to use GNSS PPS signal as a reference when tuning VCOCXO frequency
  • User I/O
    • GPIO header (0.05” pitch) connected to FPGA
    • 5X dual color (RG) LEDs connected to FPGA
    • Push button connected to FPGA
    • Buzzer connected to FPGA
  • Board Size: without connectors 125mm x 65mm (4.92” x 2.56”)


For more information on the following topics, refer to the respective documents:

  • FT601 controller resources [link]
  • MAX10 device family, refer to Intel documentation [link]
  • LMS7002M transceiver resources [link]

Board Overview

LimeNET-Micro board version 2.1 picture with highlighted major components and connections presented in Figure 1 and Figure 2. Lime Microsystems LMS7002M RF transceiver and Intel MAX10 FPGA can be found on bottom side of board, DDR2 SODIMM socket for Raspberry PI Compute module is placed on top side. There are three connector types – data and debugging (USB2.0, FPGA GPIO, Ethernet and JTAG), power (DC jack and external supply pinheader), RF (clock source output, GNSS antenna and time pulse output, RF transmit and receive ports). LimeNET-Micro 2.1 board comes in three versions and each version differs in components which are fitted on board (BOM – Bill Of Material). BOM version can be determined from resistors R34, R35, R36, R37 fitted on board (see Figure 2 “BOM version resistors” and Table 1 for version description).

Table 1. BOM version description
BOM_VER R34 R35 R36 R37 Comment
0 Fitted Fitted Fitted Fitted Lime (full version)
1 NF Fitted Fitted Fitted SDR (without duplexers and WiFi module)
2 Fitted NF Fitted Fitted GSM (with duplexers, without PoE, audio and video)
Figure 2. LimeNET-Micro top side components and connectors


Figure 3. LimeNET-Micro bottom side components


Board components description listed in the Table 2 and Table 3.

Table 2. Board components
Featured devices
Board Reference Type Description
IC1 RF transceiver Lime Microsystems LMS7002M
IC14 GNSS module GNSS receiver
IC12 FPGA Intel MAX10, 10M16SAU169C8G, 169-UBGA
IC24 USB 2.0 HUB Microchip Technology LAN9514 USB 2.0 Hub and 10/100 Ethernet Controller
IC27 USB to FIFO FTDI FT601, USB to FIFO interface bridge
IC30 Wi-Fi SDIO Wi-Fi module (WF111)
Miscellaneous devices onboard
IC13 IC Temperature sensor LM75
IC20/21 IC I2C secure key storage ATECC508A
Configuration, Status and Setup Elements
Board Reference Type Description
J3 JTAG chain pin header FPGA programming pin header for Altera USB-Blaster download cable, side connection.
J4 JTAG chain pin header FPGA programming pin header for Altera USB-Blaster download cable, 0.05” pitch
LED1,

LED2, LED3, LED4, LED5

Red-green status LEDs User defined FPGA indication.
LED6 Red-green status LEDs VCC3P3 power rail indications
LS1 Buzzer Buzzer (WST-1203UX), connected to FPGA.
J14 Jumper USB boot mode jumper
J18 Jumper External USB mode jumper
J27 Jumper Power source selection
General User Input/Output
Board Reference Type Description
J5 Pin header 8 FPGA GPIOs plus 2 power pins, 0.05” pitch
SB1 Push button Push button connected to FPGA
Memory Devices
Board Reference Type Description
IC3, IC16 EEPROM 128K (16K x 8) EEPROM connected to FPGA and LMS7002M
IC23 Flash memory 4Mbit FLASH memory connected to FPGA
Communication Ports and interfaces
Board Reference Type Description
J9 RJ45 connector Ethernet + active PoE connector
J10 USB2.0 connector 2x downstream USB2.0 type A connectors
J11 Header USB downstream header
J12 Header Upstream USB2.0 header
J13 Socket DDR2 SODIMM socket for Raspberry Pi CM3(L)
J15 USB2.0 connector microUSB2.0 upstream connector
J17 Header External UART header
J19 Connector HDMI connector for display
J22 Connector LVDS connector for display
J23 Connector LVDS connector for camera
Table 3. Board components
Clock Circuitry
Board Reference Type Description
XO1 VCOCXO 30.72 MHz voltage-controlled crystal oscillator used as a reference clock.
XO2 VCTCXO 30.72 MHz voltage-controlled, temperature compensated crystal oscillator used as a reference clock.
XO3 VCTCXO 30.72 MHz voltage-controlled, temperature compensated crystal oscillator used as a reference clock. (Not fitted by default)
XO4 VCTCXO 40.0 MHz voltage-controlled, temperature compensated crystal oscillator used as a reference clock.
IC35 OR IC37 IC Analog devices 16bit AD5662 or 8bit AD5601 Digital-to-analog converter for reference clock voltage control
IC36 IC Phase detector (ADF4002)
J25 SMA connector Reference clock input
J24 SMA connector Reference clock output
RF connectors
J1 SMA connector Transmit port or TRXA channel in duplex mode
J2 SMA connector Receive port or TRXB channel in duplex mode
J7 SMA connector GNSS module antenna connector
J20 SMA connector Antenna connector for Wi-Fi module
Power Supply
Board Reference Type Description
J28 DC input jack External 5V DC power supply input
J26 Pin header 5V DC power supply output header and main internal power rail
J6 Pin header Backup battery connection header for GNSS module. Typical 3.0V (follow recommendation in fitted GNSS module datasheet)
Other
Board Reference Type Description
J16 Card slot uSD card slot for Raspberry Pi boot
J11 Header Fan connection header