Components / I/O
7-Segment Display Pins & Pinout in Logisim
Complete 7-Segment Display pinout in Logisim: top pins (g, f, a, b) and bottom pins (e, d, c, dp) that illuminate each segment when driven High (1).
| Library | I/O |
|---|---|
| Type name | 7-Segment Display |
| Pins and defaults | top: seg_g, seg_f, seg_a, seg_b; bottom: seg_e, seg_d, seg_c, seg_dp (1 bit each) |
How the 7-Segment Works in Logisim
The 7-Segment Display in Logisim has 8 individual 1-bit input pins—4 along the top edge and 4 along the bottom edge—that directly control the 7 figure-8 bars (a through g) plus the right-hand decimal point (dp). Driving any pin High (1) lights up its corresponding segment; driving it Low (0) or leaving it unconnected (Z) keeps that segment dark.
Because the pins are arranged physically across the top and bottom edges rather than in alphabetical order, knowing the exact left-to-right pinout is essential: the top row from left to right is g, f, a, b (at x = 0, 10, 20, 30, y = 0), and the bottom row from left to right is e, d, c, dp (at x = 0, 10, 20, 30, y = 60).
Standard figure-8 segment naming goes clockwise around the outside starting from the top horizontal bar: a is top, b is upper-right, c is lower-right, d is bottom, e is lower-left, f is upper-left, and g is the center horizontal crossbar.
7-Segment Display vs. Hex Digit Display: The 7-Segment Display requires 7 separate 1-bit wires (from a BCD-to-7-segment decoder circuit or a ROM lookup table), giving you full control to draw custom characters or animations. If you already have a 4-bit binary bus and want it decoded to 0–9 and A–F automatically without building decoder gates, use the Hex Digit Display component instead.
Tip: Remember the top row order (g, f, a, b) and bottom row order (e, d, c, dp)—the top-left pin is segment g (middle bar), not segment a!
7-Segment Pins & Pinout
| Pin | Direction | Width | Location & Role |
|---|---|---|---|
| seg_g (g) | Input (Top row, 1st from left) | 1 bit | Offset (0, 0). Lights the middle horizontal segment (g) when driven to 1. |
| seg_f (f) | Input (Top row, 2nd from left) | 1 bit | Offset (10, 0). Lights the upper-left vertical segment (f) when driven to 1. |
| seg_a (a) | Input (Top row, 3rd from left) | 1 bit | Offset (20, 0). Lights the top horizontal segment (a) when driven to 1. |
| seg_b (b) | Input (Top row, 4th / rightmost) | 1 bit | Offset (30, 0). Lights the upper-right vertical segment (b) when driven to 1. |
| seg_e (e) | Input (Bottom row, 1st from left) | 1 bit | Offset (0, 60). Lights the lower-left vertical segment (e) when driven to 1. |
| seg_d (d) | Input (Bottom row, 2nd from left) | 1 bit | Offset (10, 60). Lights the bottom horizontal segment (d) when driven to 1. |
| seg_c (c) | Input (Bottom row, 3rd from left) | 1 bit | Offset (20, 60). Lights the lower-right vertical segment (c) when driven to 1. |
| seg_dp (dp) | Input (Bottom row, 4th / rightmost) | 1 bit | Offset (30, 60). Lights the bottom-right decimal point (dp) when driven to 1. |
7-Segment Truth Table & Behavior
| Digit | a (top) | b (top-R) | c (bot-R) | d (bottom) | e (bot-L) | f (top-L) | g (middle) |
|---|---|---|---|---|---|---|---|
| 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
| 2 | 1 | 1 | 0 | 1 | 1 | 0 | 1 |
| 3 | 1 | 1 | 1 | 1 | 0 | 0 | 1 |
| 4 | 0 | 1 | 1 | 0 | 0 | 1 | 1 |
| 5 | 1 | 0 | 1 | 1 | 0 | 1 | 1 |
| 6 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| 7 | 1 | 1 | 1 | 0 | 0 | 0 | 0 |
| 8 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 9 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |