Gpram
About the Gpram PCB
Gpram is an open source PCB design by emperor-hadrian, published on GitHub. It is a 2-layer board measuring 201 × 169 mm, with 55 components from 7 distinct parts.
By type, the board carries 46 ICs and 9 resistors.
From the project
Design for a DIY computer
The timing will be completely redone: A single normal clock signal, not the stupid "AB Alternating" I made up for the original. The PC will be incremented and a new instruction fetched during any non-flow-control instructions except when the GPRAM is used and the PC is in the same RAM chip (the RAM chips have 15 address lines each) as whatever is being accessed. The bus timing will also be very flexible and will be faster when possible but still slow when the memory is being accessed twice for example. Bus read/write addresses are both now 5 bits. The WRITE/MOVE instruction formats will…
Gpram bill of materials (BOM)
55 components, 7 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ~ | PinHeader_1x23_P2.54mm_Vertical | U1 |
| 2 | ~ | DIP-28_W15.24mm | U2, U17 |
| 12 | ~ | DIP-20_W7.62mm | U3, U5, U9, U10, U13, U14, U15, U16 +4 |
| 13 | ~ | DIP-14_W7.62mm | U4, U6, U24, U34, U35, U36, U37, U38 +5 |
| 4 | ~ | DIP-16_W7.62mm | U7, U8, U11, U12 |
| 14 | ~ | jumper | U18, U19, U20, U21, U22, U23, U27, U28 +6 |
| 9 | 10K 10k | 0.4_pitch_resistor | R1, R2, R3, R4, R5, R6, R7, R8 +1 |
Gpram design files
The KiCad project lives in the emperor-hadrian/stack_machine repository on GitHub; these links point at the commit this page was built from.
Gpram: common questions
How big is the Gpram PCB?
The Gpram measures 201 × 169 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Gpram?
55 components, from 7 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Gpram design files?
From the emperor-hadrian/stack_machine repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Gpram design in my own project?
The repository has no license, so all rights stay with emperor-hadrian. Use it as a reference, and ask the author before reusing the design.
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