Edit in JSFiddle

var map = new ol.Map({
        target: 'map',
        layers: [
          new ol.layer.Tile({
            title: "Global Imagery",
            source: new ol.source.TileWMS({
              url: 'http://maps.opengeo.org/geowebcache/service/wms',
              params: {LAYERS: 'bluemarble', VERSION: '1.1.1'}
            })
          })
        ],
        view: new ol.View({
          projection: 'EPSG:4326',
          center: [0, 0],
          zoom: 0,
          maxResolution: 0.703125
        })
      });

<div id="map"></div>

#map {
        height: 256px;
        width: 512px;
      }