RAM
About the RAM PCB
RAM is an open source PCB design by TheJustMoose, published on GitHub. It is a 2-layer board measuring 99.1 × 99.1 mm, with 26 components from 13 distinct parts.
Other key parts include the 74LS283, CY62256-70PC, 74HC00 and W27C512. By type, the board carries 7 ICs, 6 connectors, 6 resistors, 3 diodes, 3 capacitors and 1 transistor.
From the project
Handmade CPU. See README.md
Not a very scary instruction set discrete logic processor.
8 bit data 16 bit address / 64KB RAM 17 bit address (in V register) / 128KW Dual Bank Video RAM 16 instructions 8 data registers and 4 pointer registers in 2 banks 1 flags register in IO port 32 input ports and 32 output ports (You can write a constant to the first 8 ports. Only registers can be written to the remaining ports.) Assembled from 74HCxx series ICs!
Main components on the RAM
RAM bill of materials (BOM)
26 components, 13 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 4 | 74LS283 | DIP-16_W7.62mm | U1, U3, U4, U5 |
| 1 | CY62256-70PC | DIP-28_W15.24mm | U2 |
| 1 | 74HC00 | DIP-14_W7.62mm | U6 |
| 1 | W27C512 | DIP-28_W15.24mm | U7 |
| 1 | IRLML5203 | SOT-23 | Q1 |
| 3 | Conn_01x09_Male | PinHeader_1x09_P2.54mm_Vertical | J1, J2, J3 |
| 1 | Conn_01x03_Male | PinHeader_1x03_P2.54mm_Vertical | J4 |
| 1 | Conn_01x08_Male | PinHeader_1x08_P2.54mm_Vertical | J5 |
| 1 | Screw_Terminal_01x02 | TerminalBlock_Phoenix_MKDS-1,5-2_1x02_P5.00mm_Horizontal | J6 |
| 3 | LED | LED_Rectangular_W5.0mm_H2.0mm | D1, D2, D3 |
| 3 | 0.1uF | C_Disc_D7.5mm_W5.0mm_P10.00mm | C1, C2, C3 |
| 3 | 1k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3 |
| 3 | 10k | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R5, R6 |
RAM design files
The KiCad project lives in the TheJustMoose/74HCPU repository on GitHub; these links point at the commit this page was built from.
- Layouthard/!RAM/RAM.kicad_pcb
- Schematichard/!RAM/RAM.kicad_sch
RAM: common questions
How big is the RAM PCB?
The RAM measures 99.1 × 99.1 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the RAM?
26 components, from 13 distinct parts. The full bill of materials is listed on this page.
Where can I download the RAM design files?
From the TheJustMoose/74HCPU repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the RAM design in my own project?
The repository has no license, so all rights stay with TheJustMoose. Use it as a reference, and ask the author before reusing the design.
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