Flags
About the Flags PCB
Flags is an open source PCB design by Velko, published on GitHub under the MIT license. It is a 4-layer board measuring 62.2 × 21.6 mm, with 42 components from 24 distinct parts.
Other key parts include the 74HC02, 74HC08, 74HC157, 74HC173 and 74HC125. By type, the board carries 15 resistors, 8 diodes, 7 capacitors, 6 ICs and 6 connectors.
It belongs with the retro computing designs in this gallery.
From the project
Homebrew 8-bit CPU
After watching [series of videos][eater-net-8bit] by Ben Eater building an 8-bit computer from scratch, I was hooked. Various thoughts for improvements and experiments was running through my mind. But first I have to build one. Improvements will come later. Whom am I kidding? I'll never be able to build an exact replica, I'll incorporate improvements as I go.
Main components on the Flags
Flags bill of materials (BOM)
42 components, 24 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74HC02 | SOIC-14_3.9x8.7mm_P1.27mm | U1 |
| 1 | 74HC08 | SOIC-14_3.9x8.7mm_P1.27mm | U2 |
| 1 | 74HC157 | SOIC-16_3.9x9.9mm_P1.27mm | U3 |
| 2 | 74HC173 | SOIC-16_3.9x9.9mm_P1.27mm | U4, U5 |
| 1 | 74HC125 | SOIC-14_3.9x8.7mm_P1.27mm | U6 |
| 1 | Bus | PinHeader_1x08_P2.54mm_Vertical | J1 |
| 1 | Control | PinHeader_1x04_P2.54mm_Vertical | J2 |
| 1 | Sync | PinHeader_1x04_P2.54mm_Vertical | J3 |
| 1 | Power | PinHeader_2x02_P2.54mm_Vertical | J4 |
| 1 | Flags_Bus | PinHeader_1x04_P2.54mm_Vertical | J5 |
| 1 | Ctrl_Out | PinHeader_1x04_P2.54mm_Vertical | J6 |
| 1 | Z | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1 |
| 1 | V | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D2 |
| 1 | N | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D3 |
| 1 | C | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D4 |
| 1 | LOAD | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D5 |
| 1 | BOUT | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D6 |
| 1 | CALC | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D7 |
| 1 | CARRY | LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D8 |
| 6 | 100nF | C_0805_2012Metric_Pad1.15x1.40mm_HandSolder | C1, C2, C3, C4, C5, C6 |
Show 4 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 10μF | C_0805_2012Metric_Pad1.15x1.40mm_HandSolder | C7 |
| 6 | 10K | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R1, R2, R11, R12, R13, R14 |
| 8 | 330 | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R3, R4, R5, R6, R7, R8, R9, R10 |
| 1 | 100K | R_0805_2012Metric_Pad1.15x1.40mm_HandSolder | R15 |
Flags design files
The KiCad project lives in the Velko/8-bit-CPU repository on GitHub; these links point at the commit this page was built from.
Flags: common questions
How big is the Flags PCB?
The Flags measures 62.2 × 21.6 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Flags?
42 components, from 24 distinct parts. The full bill of materials is listed on this page.
Where can I download the Flags design files?
From the Velko/8-bit-CPU repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the Flags design in my own project?
Yes, under the terms of its MIT license, which Velko chose for the repository.
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