Master electronic device and communication method of the same

A master electronic device used to perform communication with a slave electronic device is provided. The master electronic device includes a power module, an input and output (I/O) module, a processing module, a sample and hold module and a control module. The power module outputs power having a default operation voltage. The I/O module operates according to the power having the default operation voltage. The processing module controls the I/O module to generate and transmit a command signal to the slave electronic device. The sample and hold module receives and samples a response signal from the slave electronic device. The control module determines a slave operation voltage according to a high state voltage level of the response signal, so as to further control the power module to generate power having the slave operation voltage such that the I/O module operates accordingly.