LimeNET Micro is an open spec, 125 x 65mm fully embedded SDR board, featuring the Raspberry Pi Compute Module 3, MAX10 FPGA, u-blox GNSS, RF transceiver, Ethernet with PoE, and optional enclosures. It is Lime’s first fully embedded SDR board. The LimeNET Micro will be available for order in Dec. 6, starting at $269, including the integrated Raspberry Pi Compute Module 3, with shipments slated for Feb. 25, 2019. Other packages include adding enclosures and omnidirectional antennas. The new LimeNET Micro mainboard is slightly larger than the 100 x 60mm LimeSDR Mini, and the double enclosure options are about the same size as the Mini enclosure. The Micro enables more compact systems by integrating the 67.6 x 31m Raspberry Pi CM3 module rather than requiring an attached desktop or SBC computer.
The LimeNET Micro is also fitted with an Intel/Altera MAX 10 FPGA with 16k programmable logic gates. It also integrates Lime’s SDR-optimized LMS7002M RF transceiver. The Micro and Mini have similar specs, including the 10MHz to 3.5GHz range, 12-bit sample depth, full-duplex operation, single TX and RX channels, and precision oscillator. The LimeNET Micro RF 0.27MHz bandwidth and 1.0MSPS sample rate are much lower than the LimeNET Mini. This could be due to the lower processing power of the RPi CM3 compared to other attached computers, or to additional onboard components. Like the original RPi 3, the CM3 module has a quad-core -A53 Broadcom BCM2837 clocked to 1.2GHz. It comes with 1GB LPDDR2 and 4GB eMMC. The Micro has a $30 option for an adapter and ribbon cable that allows you to attach a full-sized Raspberry Pi. It’s not clear if the attached SBC plays any role in LimeNET Microprocessing or if it simply enables easier access to I/O features such as WiFi/BT, which are absent on the CM3.