... voltage: 1.9 ~ 3.6V Ultra Small: Built-in 2.4GHz antenna, small size, 12x19mmNRF24L01+ wireless module ApplicationsMouse, keyboard, ... variety of low-cost MCUNo MCU with SPI Interface20 pin 4x4mm QFN lead-free packages are very few external ... operationMaximum possible noise reductionPIN FeaturesDirectionPIN 1VCCInput 1.9V-3.6V PIN 2CEMode selection TR/RXIPIN 3CSNSPI Enable, Enable LowIPIN 4SCKSPI ...