Help needed! Read digital data without UART or Bus line

Currently I'm using a C8051F120 microcontroller to receive information from a demodulator via UART. However, now I'm required to recieve data in non-UART format (without start and stop bit).

Currently the demodulator doesn't support bus line. I would like to ask what are the recommended methods to read signals(square wave) from the demodulator and display on the computer? It could be direct connection from the demodulator to the computer without using the microcontroller.

Also If I were to use a bus line, how would the implementation be like?