ROM
About the ROM PCB
ROM is an open source PCB design by TheJustMoose, published on GitHub. It is a 2-layer board measuring 149.9 × 99.1 mm, with 40 components from 13 distinct parts.
Other key parts include the AM29F200BB-SO44, 74LS573, 74LS245 and 74HC00. By type, the board carries 14 connectors, 9 resistors, 7 ICs, 7 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 ROM
ROM bill of materials (BOM)
40 components, 13 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | AM29F200BB-SO44 | DIP-44_W15.24mm | U1 |
| 2 | 74LS573 | DIP-20_W7.62mm | U2, U3 |
| 3 | 74LS245 | DIP-20_W7.62mm | U4, U5, U7 |
| 1 | 74HC00 | DIP-14_W7.62mm | U6 |
| 1 | IRLML5203 | SOT-23 | Q1 |
| 9 | Conn_01x09_Male | PinHeader_1x09_P2.54mm_Vertical | J1, J2, J3, J5, J6, J7, J8, J12 +1 |
| 1 | Screw_Terminal_01x02 | TerminalBlock_Phoenix_PT-1,5-2-5.0-H_1x02_P5.00mm_Horizontal | J4 |
| 4 | Conn_01x01_Male | PinHeader_1x01_P2.54mm_Vertical | J9, J10, J11, J14 |
| 2 | HDSP-4850 | HDSP-4850 | BAR1, BAR2 |
| 1 | 0.1uF | C_Rect_L24.0mm_W7.0mm_P22.50mm_MKT | C1 |
| 6 | 0.1uF | C_Disc_D7.5mm_W5.0mm_P7.50mm | C2, C3, C4, C5, C6, C7 |
| 6 | 10K | R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R3, R4, R5, R6 |
| 3 | R_Network08 | R_Array_SIP9 | RN1, RN2, RN3 |
ROM 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/!ROM/ROM.kicad_pcb
- Schematichard/!ROM/ROM.kicad_sch
ROM: common questions
How big is the ROM PCB?
The ROM measures 149.9 × 99.1 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the ROM?
40 components, from 13 distinct parts. The full bill of materials is listed on this page.
Where can I download the ROM 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 ROM 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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