This is a hex to 7-segment converter. Type digits 0–F and get the segment byte for each. On a common-cathode display with bit 0 = a, 0 is 0x3F and F is 0x71. Click a bar to build a custom glyph.
Examples — click a swatch
Click a segment to flip it.
Append a digit, or DP on the last one
Click a value to copy it
0–F lookup — click a row. Hex follows the bit order above. Common anode is the 8-bit invert of common cathode.
This is a hex to 7-segment display converter. Each hex digit 0–F becomes one byte that lights bars a–g (and optional DP). On the usual common-cathode wiring with bit 0 = a (gfedcba), 0 is 0x3F, 1 is 0x06, 8 is 0x7F, F is 0x71. That is a display lookup table, not ASCII: HEX to ASCII turns bytes into characters. Invert a byte on Hex bitwise if you only need NOT.
Type digits such as CAFE, or pick a chip (CAFE, 8, DEAD, 12.3, 0x3F 0x06). Mode Digits → patterns encodes the string; Patterns → digits reads bytes back. Display chooses common cathode (1 lights a bar) or common anode (0 lights a bar). Bit order is gfedcba (a = bit 0) or abcdefg (g = bit 0); DP stays bit 7. The pad appends 0–F; DP toggles a point on the last digit. Click a bar to flip it — the page switches to pattern mode and rewrites the bytes. Copy result copies the hex bytes; chips copy one byte or the C array. The 0–F table follows the bit order you selected; click a row to load that digit.
Logical bits are always a=0 … g=6, DP=7. Packing permutes them for abcdefg so 0 becomes 0x7E instead of 0x3F. Common anode is the 8-bit NOT of that packed byte (0 → 0xC0 on gfedcba). A period after a digit, as in 12.3, sets DP on that digit. Unknown glyphs decode as ?. b and d use the lowercase-style patterns (0x7C, 0x5E) so they do not look like 8 and 0. A 7447 BCD decoder only draws 0–9 and uses different tails for 6 and 9 — this table is the hex MCU convention, not 7447.
Arduino or STM32 code that writes a port to a 7-segment part, a clock or instrument panel, checking why a digit looks like a photographic negative (wrong anode/cathode), or pasting const uint8_t digits[] into firmware.
0x3F is gfedcba with a at bit 0 and g off. 0x7E is the same glyph with g at bit 0 (abcdefg). Switch Bit order if your schematic wires a to the high pin.
That display lights when the pin is low. Pick Common anode here, or NOT the cathode byte at 8 bits on the bitwise page.
Yes. Click bars, or start from H, L, P, U, or a dash (those also decode). There is no readable 7-segment K, M, or W.