In this letter, an adaptive equalizer with an inter-symbol interference (ISI) level measurement using a periodic training pattern is presented. The compensation level of the equalizer is determined by measuring ISI level and fed back to the feed-forward equalizer. The proposed algorithm is verified with a 100-cm flexible flat cable (FFC) at 10Gb/s data rate using a 90nm CMOS process technology. Compensation range is from 15dB to 33dB with a tuning range of 18dB, and the current consumption is 7.6mA at 1V power supply.