I have a Terasic DE1, and have imported the maker's pinout file, which contains pin assignments for HEX digits. However, I noticed that each HEX digit has a dot next to it and I cannot find any pin assignments for those dots. I'm wondering if they are disabled or I can somehow map them myself. Can you help?

  • \$\begingroup\$ HEX is seldom used with decimals so the decimal points are often left unconnected as they are unused. They save on a driver transistor as you only have to multiplex the 7 segments. It might be possible to clone the segment drive circuit and connect it to the likely spare 8th bit in a port. Software libraries might need changing to get support. Perhaps you need to implement a decimal display routine from 0.001 to 9999. instead of 0000 to FFFF hex \$\endgroup\$ – KalleMP Oct 9 '16 at 20:09

From the "Using the 7-segment Displays" section of the user's manual for the DE1:

Note that the dot in each display is unconnected and cannot be used.

  • \$\begingroup\$ Well that's nice... I suppose you could tack a wire on to the relevant pin on the LED, and connect it to a spare I/O pin... \$\endgroup\$ – Brian Drummond Oct 9 '16 at 9:40

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