Jul 10, 2012 · Raspberry Pi 7 segment displays This post shows how to drive two 7 segment displays from 6 gpio pins on the Raspberry Pi without a continual refresh loop. The software is simple with very low cpu usage - only processing when you want to change the displayed numbers. that display. In order to use the display it would be convenient to have some logic which maps from normal binary numbers (e.g.: 0110 = 6) to the corresponding segments which must be illuminated. We will call this part a BCD-to-7-segment decoder. Remember BCD is Binary Coded Decimal, in which 4 bits are used to represent the values from 0-9. A binary coded decimal (BCD) to 7-segment display decoder such as the TTL 74LS47 or 74LS48, have 4 BCD inputs and 7 output lines, one for each LED segment. This allows a smaller 4-bit binary number (half a byte) to be used to display all the denary numbers from 0 to 9 and by adding two displays together, a full range of numbers from 00 to 99 can be displayed with just a single byte of eight data bits. Binary Coded Decimal (BCD) to 7 Segment Display > this is my first instructables , sorry as it is not well detailed , electronics parts used are a 7 segment display , 7 - 470 ohms resistors , 4- k ohms resistors, ic - 4511 , some wires and a 4 position dip switch (here i used a 8 position switch) ..