Q2a
About the Q2a PCB
Q2a is an open source PCB design by joewing, published on GitHub. It is a 2-layer board measuring 154 × 160 mm, with 154 components from 22 distinct parts.
Other key parts include the Clock, State, IO, Opcode and 14. By type, the board carries 50 resistors, 43 diodes, 32 capacitors, 26 ICs, 2 connectors and 1 crystal.
From the project
12-bit single-board discrete transistor computer
Hardware for the Q2 12-bit computer made from programmable logic devices. Compared to the original Q2, the Q2A should be easier to have fabricated (it uses through-hole components making it easy to hand assemble). In addition, the Q2A has a faster clock and a nicer enclosure.
Note that the current iteration of the Q2A does not support the memory extension device or I2C.
Main components on the Q2a
Q2a bill of materials (BOM)
154 components, 22 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | Clock | DIP-20_W7.62mm_Socket | U1 |
| 1 | State | DIP-20_W7.62mm_Socket | U2 |
| 1 | IO | DIP-20_W7.62mm_Socket | U3 |
| 1 | Opcode | DIP-20_W7.62mm_Socket | U4 |
| 1 | 14 | DIP-14_W7.62mm_Socket | U5 |
| 12 | Slice | DIP-20_W7.62mm_Socket | U6, U10, U11, U12, U13, U14, U15, U16 +4 |
| 1 | 62256 | DIP-28_W15.24mm_Socket | U8 |
| 1 | 6264 | DIP-28_W15.24mm_Socket | U9 |
| 4 | 245 | DIP-20_W7.62mm_Socket | U18, U19, U20, U21 |
| 1 | Field 2 | DIP-20_W7.62mm_Socket | U24 |
| 1 | Field 1 | DIP-20_W7.62mm_Socket | U25 |
| 1 | Field 0 | DIP-20_W7.62mm_Socket | U26 |
| 1 | CXO | DIP-8_W7.62mm_Socket | X1 |
| 1 | Barrel_Jack_MountingPin | BarrelJack_Horizontal | J1 |
| 1 | C9138 Programmer BOOMELE(Boom Precision Elec) | IDC-Header_2x20_P2.54mm_Vertical | J3 |
| 29 | LED | LED_0805_2012Metric | D1, D2, D3, D4, D5, D6, D7, D8 +21 |
| 14 | BAT43W 1N4148 Changjiang Electronics Tech (CJ) | D_MiniMELF | D30, D31, D32, D33, D34, D35, D36, D37 +6 |
| 31 | 0.1u | C_Disc_D5.0mm_W2.5mm_P2.50mm | C1, C2, C3, C4, C5, C6, C7, C8 +23 |
| 1 | 47u | CP_Radial_D6.3mm_P2.50mm | C9 |
| 17 | 10k | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R1, R2, R3, R4, R5, R6, R11, R12 +9 |
Show 2 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 4 | 100k | R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_Vertical | R7, R8, R9, R10 |
| 29 | 10k | R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R19, R20, R21, R22, R23, R24, R25, R26 +21 |
Q2a design files
The KiCad project lives in the joewing/q2 repository on GitHub; these links point at the commit this page was built from.
Q2a: common questions
How big is the Q2a PCB?
The Q2a measures 154 × 160 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Q2a?
154 components, from 22 distinct parts. The full bill of materials is listed on this page.
Where can I download the Q2a design files?
From the joewing/q2 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Q2a design in my own project?
The repository has no license, so all rights stay with joewing. Use it as a reference, and ask the author before reusing the design.
