SX1272Lib updated in order to be RTOS aware

Fork of SX1272Lib by Semtech

Since Semtech original SX1272 library used InterruptIn and Timout mbed-os classes, whose ISRs are not allowed to lock RTOS mutexes, any SPI-related operation was doomed to fail. Indeed, SPI transactions functions are always nested inside a spi-level mutex lock/unlock pair in order to provide for thread access safety. A typical case occurs for example when radio is set to sleep state after a RX timeout.

This fork solves such problems by mean of a EventQueue/Thread pair, where any InterruptIn and Timeout ISRs actually enqueue callback calls.

Take a look at usage example at https://github.com/maiorfi/mbedos_lablet_lora_1