Backtobasic
About the Backtobasic PCB
Backtobasic is an open source PCB design by marcusyoung, published on GitHub. It is a 4-layer board measuring 246.4 × 185.4 mm, with 277 components from 40 distinct parts.
Other key parts include the LM555, 74LS04, 74LS08, 74LS32 and 74LS245. By type, the board carries 104 resistors, 85 diodes, 53 ICs, 24 capacitors, 8 switches and 1 connector.
From the project
Rediscovering 8-bit computing — hardware fundamentals, nostalgia, and code
Repo about rediscovering 8-bit computers, including programming in BASIC and ASM and building Ben Eater's 8-bit breadboard computer.
Main components on the Backtobasic
Backtobasic bill of materials (BOM)
277 components, 40 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 4 | LM555 | DIP-8_W7.62mm | U1, U2, U3, U39 |
| 5 | 74LS04 | DIP-14_W7.62mm | U4, U28, U29, U49, U53 |
| 3 | 74LS08 | DIP-14_W7.62mm | U5, U23, U46 |
| 1 | 74LS32 | DIP-14_W7.62mm | U6 |
| 6 | 74LS245 | DIP-20_W7.62mm | U7, U10, U13, U17, U30, U36 |
| 8 | 74LS173 | DIP-16_W7.62mm | U8, U9, U11, U12, U14, U15, U19, U34 |
| 2 | 74LS86 | DIP-14_W7.62mm | U16, U18 |
| 2 | 74LS283 | DIP-16_W7.62mm | U20, U21 |
| 1 | 74LS02 | DIP-14_W7.62mm | U22 |
| 2 | 74189 | DIP-16_W7.62mm | U24, U25 |
| 4 | 74LS157 | DIP-16_W7.62mm | U26, U27, U32, U33 |
| 2 | 74LS00 | DIP-14_W7.62mm | U31, U51 |
| 2 | 74LS161 | DIP-16_W7.62mm | U35, U48 |
| 1 | 74LS76 | DIP-16_W7.62mm | U37 |
| 1 | 74LS139 | DIP-16_W7.62mm | U38 |
| 4 | 7SEGMENT_CC | 7SegmentLED_LTS6760_LTS6780 | U40, U41, U42, U43 |
| 1 | 74LS273 | DIP-20_W7.62mm | U44 |
| 3 | 28C16 | DIP-24_W15.24mm_Socket | U45, U47, U52 |
| 1 | 74LS138 | DIP-16_W7.62mm | U50 |
| 1 | USB_B | USB_B_OST_USB-B1HSxx_Horizontal | J1 |
Show 20 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 1M | Potentiometer-5.5mm | RV1 |
| 2 | SW_Push | SW_PUSH_6mm_H5mm | SW1, SW4 |
| 3 | SW_SPDT | DPDT-pushbutton | SW2, SW6, SW7 |
| 1 | SW_DIP_x08 | SW_DIP_SPSTx08_Slide_9.78x22.5mm_W7.62mm_P2.54mm | SW3 |
| 1 | SW_DIP_x04 | SW_DIP_SPSTx04_Slide_9.78x12.34mm_W7.62mm_P2.54mm | SW5 |
| 1 | Reset | SW_PUSH_6mm_H5mm | SW8 |
| 1 | G*** | BenEater | svg2mod |
| 21 | BLUE | LED_D5.0mm | D1, D26, D27, D28, D29, D58, D59, D60 +13 |
| 44 | RED | LED_D5.0mm | D2, D3, D4, D5, D6, D7, D8, D9 +36 |
| 8 | YELLOW | LED_D5.0mm | D30, D31, D32, D33, D44, D45, D46, D47 |
| 12 | GREEN | LED_D5.0mm | D34, D35, D49, D50, D52, D53, D55, D56 +4 |
| 16 | 0.1µF | C_Disc_D4.3mm_W1.9mm_P5.00mm | C1, C3, C10, C11, C12, C13, C14, C15 +8 |
| 6 | 0.01µF | C_Disc_D4.3mm_W1.9mm_P5.00mm | C2, C4, C5, C7, C8, C9 |
| 1 | 1µF | CP_Radial_D5.0mm_P2.00mm | C6 |
| 1 | 10µF | CP_Radial_D5.0mm_P2.00mm | C24 |
| 10 | 1K | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R2, R3, R5, R6, R58, R63, R64 +2 |
| 1 | 1M | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R4 |
| 83 | 220 | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R7, R16, R17, R18, R19, R20, R21, R22 +75 |
| 9 | 10k | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R8, R9, R10, R11, R12, R13, R14, R15 +1 |
| 1 | 100K | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R66 |
Backtobasic design files
The KiCad project lives in the marcusyoung/backtobasic repository on GitHub; these links point at the commit this page was built from.
Backtobasic: common questions
How big is the Backtobasic PCB?
The Backtobasic measures 246.4 × 185.4 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Backtobasic?
277 components, from 40 distinct parts. The full bill of materials is listed on this page.
Where can I download the Backtobasic design files?
From the marcusyoung/backtobasic repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Backtobasic design in my own project?
The repository has no license, so all rights stay with marcusyoung. Use it as a reference, and ask the author before reusing the design.