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Limedrv

1 What is Limedrv

Limedrv is a libLimeSuite Golang wrapper. It is designed to be easy of use and to be very easily integrated with any type of DSP inside go.


2 Getting Started

From now on, this article assumes that you know how to setup your golang environment and can build simple hello world programs. If you don't know or never played with GoLang, please refer to: https://golang.org/doc/install


3 Enumerating Devices

The first thing we need to be able to enumerate all devices that are plugged in. For that, let's create simple program that prints out every lime device that it finds.

package main

import (
        "github.com/myriadrf/limedrv"
        "log"
)

func main() {
        devices := limedrv.GetDevices()
        log.Printf("Found %d devices\n", len(devices))

        for i, v := range devices {
                log.Printf("%d: %s\n", i, v.DeviceName)
        }
}

Limedrv-Sample-0.png

Now we can try to open the device and list its capabilities:

package main

import (
        "github.com/myriadrf/limedrv"
        "log"
)

func main() {
        devices := limedrv.GetDevices()
        log.Printf("Found %d devices\n", len(devices))

        if len(devices) == 0 {
                log.Fatal("No devices found!")
        }

        d := devices[0]

        log.Printf("Opening %s\n", d.DeviceName)
        dev := limedrv.Open(d) // Open the selected device
        defer dev.Close()      // Defer the close of the device

        log.Println(dev)
}

Limedrv-deviceopen-print.png


4 Receiving Samples

Receiving data is also simple with limedrv:

package main

import (
    "github.com/myriadrf/limedrv"
    "log"
)

var stop chan bool
var receivedSamplesChunk = 0

func OnSamples(data []complex64, channel int, timestamp uint64) {
    log.Printf("Received %d samples on channel #%d with timestamp %d\n", len(data), channel, timestamp)
    receivedSamplesChunk++

    if receivedSamplesChunk == 10 {
        stop <- true
    }
}

func main() {

    stop = make(chan bool) // Create Stop Channel

    devices := limedrv.GetDevices()
    log.Printf("Found %d devices\n", len(devices))

    if len(devices) == 0 {
        log.Fatal("No devices found!")
    }

    d := devices[0]

    log.Printf("Opening %s\n", d.DeviceName)
    dev := limedrv.Open(d) // Open the selected device
    defer dev.Close()      // Defer the close of the device

    dev.SetCallback(OnSamples) // Set Samples Callback
    dev.SetSampleRate(3e6, 4)  // Set Sample Rate to 2 msps and 4x oversampling
    // Get RX Channel 0 (A)
    channel := dev.RXChannels[limedrv.ChannelA]

    channel.
        SetCenterFrequency(106.3e6).        // Set Center Frequency
        SetAntennaByName(limedrv.LNAW).     // Set LNAW Port
        SetLPF(1.5e6).                      // Set LPF to 1 MHz
        EnableLPF().                        // Enable the LPF
        SetGainNormalized(0.2).             // Set gain to 0.2 in Normalized value (0 -> 1)
        SetDigitalLPF(500e3).               // Set Digital LPF (GFIR) to 500kHz
        EnableDigitalLPF().                 // Enable Digital LPF (GFIR)
        Enable()                            // Enable the RX Channel

    log.Println("Starting LimeSDR")
    dev.Start()

    <-stop // Block main routine waiting for stop signal

    log.Println("Stopping LimeSDR")
    dev.Stop()
}

Limedrv-receiving-data.png

You can also enable MIMO (on supported devices) by just enabling the second channel:

    dev.RXChannels[limedrv.ChannelA].
        SetCenterFrequency(106.3e6).        // Set Center Frequency
        SetAntennaByName(limedrv.LNAW).     // Set LNAW Port
        SetLPF(1.5e6).                      // Set LPF to 1 MHz
        EnableLPF().                        // Enable the LPF
        SetGainNormalized(0.2).             // Set gain to 0.2 in Normalized value (0 -> 1)
        SetDigitalLPF(500e3).               // Set Digital LPF (GFIR) to 500kHz
        EnableDigitalLPF().                 // Enable Digital LPF (GFIR)
        Enable()                            // Enable the RX Channel channel.
    dev.RXChannels[limedrv.ChannelB].
        SetCenterFrequency(106.3e6).        // Set Center Frequency
        SetAntennaByName(limedrv.LNAH).     // Set LNAW Port
        SetLPF(1.5e6).                      // Set LPF to 1 MHz
        EnableLPF().                        // Enable the LPF
        SetGainNormalized(0.2).             // Set gain to 0.2 in Normalized value (0 -> 1)
        SetDigitalLPF(500e3).               // Set Digital LPF (GFIR) to 500kHz
        EnableDigitalLPF().                 // Enable Digital LPF (GFIR)
        Enable()                            // Enable the RX Channel

Limedrv-mimo-mode.png

5 Transmitting Samples

Currently limedrv only supports RX. But TX support is planned.