The increasing demand for miniaturized and portable spectrometers across diverse applications drives the development of computational spectrometers based on algorithmic reconstruction. This work presents an integrated computational spectrometer fabricated on a silicon-on-insulator (SOI) substrate. The device utilizes six cascaded tunable add-drop micro-rings (MRRs), each with two tuning states, providing 128 distinct filtering channels within a compact footprint of 0.62 mm². Experimental results demonstrate successful spectral reconstruction within the 1525-1565 nm band, achieving a resolution of 40 pm. The average power consumption of the device is 140 mW.