and display it on 3 LED displays.
Pick an EPROM, preferably cheap. We will program about 1 kib. Shift up your 8 bit value (or not, bit position is not that important here) you need a 2 bit counter to cycle the addresses for readout. Encode the translated value to the 8 bits to directly seven segment displays. Use state 00 to read the value and the succesive states to display the three digits. With an oscillator, maybe half a dozen parts.
Joseph