18 open source boards using the 74LS138
Real designs built with the 74LS138, from public GitHub projects: a quick way to see how others power, decouple and connect it. Each board comes with its KiCad files, full parts list and a render — and you can simulate its firmware on HardLabs.
Multi
homebrew8088
243.8 × 172.7 mm85 parts2LGPL-3.0238
Vic2020mainboard
danwerner21
357.8 × 124.5 mm127 parts2LNo license78
TI99 22
350 × 224.3 mm242 parts2LNo license50
TEC-1G
MarkJelic
63.5 × 85.6 mm31 parts2LGPL-3.046
TRS-80 Color Computer 3
qbancoffee
280 × 156.3 mm205 parts2LGPL-3.040
Dragon64
333.2 × 205.9 mm220 parts2LNo license34
ESP32TI99 22
244 × 244 mm257 parts4LNo license4
AVR/ArduinoAPL1
acwright
150 × 100 mm44 parts2LCERN-OHL-P-2.01
V40 64K 640K ISA
145.8 × 91.4 mm23 parts2LGPL-3.0238
TRS-80 Color Computer 2 NTSC ( 26-3134B & 26-3136B)
230 × 170 mm150 parts2LGPL-3.040
Backup
333.2 × 205.9 mm218 parts2LNo license34
Backup1
333.2 × 205.9 mm218 parts2LNo license34
Z80CTCDART2
lynchaj
100 × 100 mm73 parts2LNo license31
128 X 16 RAM V4 FINAL
ibm2030
180 × 95 mm108 parts4LNo license13
PPort
104 × 73.9 mm20 parts2LGPL-3.0238
Z80VDC
100 × 100 mm63 parts2LNo license31
64K 640K ISA
104 × 73.9 mm12 parts2LGPL-3.0238
512k
104 × 73.9 mm10 parts2LGPL-3.0238
The 74LS138 in open source designs
The gallery holds 18 open source boards using the 74LS138 from 10 GitHub repositories; a typical one measures about 205 × 112.2 mm and carries around 97 components.
89% are two-layer designs, the rest use four layers or more, and 50% carry an open source license.
The most starred is Multi by homebrew8088.
Parts used alongside the 74LS138
Microcontrollers on boards using the 74LS138
What boards using the 74LS138 are built for
74LS138: common questions
Where can I find a 74LS138 reference design?
Each of the 18 boards on this page is a real design using the 74LS138. Open one to see how it is wired up, with the full BOM, a render of the layout and links to its KiCad files.
What parts are used alongside the 74LS138?
The 74LS04, 74LS00, 74LS245, 74LS244 and 74LS07 appear in the most repositories here.
Which microcontrollers do boards using the 74LS138 use?
Most are built on ESP32 (1) and AVR/Arduino (1).
How big is a typical board using the 74LS138?
The median is 205 × 112.2 mm, and 89% are two-layer designs.
What is the most popular open source board using the 74LS138?
By GitHub stars, Multi by homebrew8088, with 238 stars.
Can I simulate one of these boards using the 74LS138 before building it?
Yes. HardLabs turns a board's netlist and BOM into a working simulation, so you can boot and test firmware against it with no hardware on your desk.