79 TTSKY26A BCD to 7-Segment Decoder
79 : TTSKY26A BCD to 7-Segment Decoder
- Author: William Anthony
- Description: Tiny Tapeout HEX-to-7-segment decoder (0-9,A,b,C,d,e,F) with blank, lamp-test, decimal-point, and active-low mode support.
- GitHub repository
- Open in 3D viewer
- Clock: 50000000 Hz
TTSKY26A-BCD-TO-7SEGMENT
How it works
This design translates one 4-bit input into a 7-segment HEX glyph pattern.
Visual explanation
The additional display reference photos are available in docs/extra-img.
Functional pipeline:
- HEX decode:
- Inputs 0..15 map to 0,1,2,3,4,5,6,7,8,9,A,b,C,d,e,F.
- Display control:
- display_enable gates the output path.
- blank forces all segments off.
- lamp_test forces all segments on.
- Output-mode adaptation:
- active-high output mode (common-cathode)
- active-low output mode (common-anode)
- Status reporting:
- valid digit flag
- invalid digit flag
- display_on flag
- active_low_mode echo
Pin usage summary
-
ui[3:0]: HEX nibble
-
ui[4]: display_enable
-
ui[5]: blank
-
ui[6]: lamp_test
-
ui[7]: decimal point input
-
uo[6:0]: segments {a,b,c,d,e,f,g}
-
uo[7]: decimal point output
-
uio[0]: active_low_mode
-
uio_out[7:4]: status flags
How to test
Cocotb regression
cd test
make
Standalone Verilog check
cd test
iverilog -o sim_bcd_verify.vvp -I ../src \
../src/project.v \
../src/bcd_to_7seg_decoder.v \
../src/seg_display_control.v \
../src/seg_output_mode.v \
tb_verify.v
vvp sim_bcd_verify.vvp
References
- LD3631ABU Datasheet (0.36" LED Digital Tube): https://imrnrwxhplpp5p.leadongcdn.com/LD3631ABU-aidlkBqmKonSRniilqorniq.pdf
- Shopee target module page: https://shopee.co.id/product/2178321/13198892939
- GeeksforGeeks, BCD to 7 Segment Decoder: https://www.geeksforgeeks.org/digital-logic/bcd-to-7-segment-decoder/
- Electronics Tutorials, BCD to 7 Segment Decoder: https://www.electronics-tutorials.ws/combination/comb_6.html
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | HEX bit 0 | Segment g | Active-low mode (1=common-anode, 0=common-cathode) |
| 1 | HEX bit 1 | Segment f | Reserved |
| 2 | HEX bit 2 | Segment e | Reserved |
| 3 | HEX bit 3 | Segment d | Reserved |
| 4 | Display enable | Segment c | valid digit active |
| 5 | Blank | Segment b | invalid digit active |
| 6 | Lamp test | Segment a | display on |
| 7 | Decimal point input | Decimal point output | active-low mode echo |