The present invention provides a device with low power and high performance, which can be applied to sensor nodes, a sensor node using the same, an access controller, a data transfer method, and execute a processing method in a microcontroller. The device has: an MRAM; a non-volatile CPU configured to include a nonvolatile memory; a non-volatile FPGA-ACC configured to include a nonvolatile memory and execute a part of operations on the nonvolatile CPU; and a power-gating control unit that controls power supply to each memory cell in the MRAM, the non-volatile CPU, and the non-volatile FPGA-ACC. The device is further provided with an access controller that controls accesses to the MRAM by reading data in advance and backing up the data when data is to be read from the MRAM.