2 layers333.4 × 124.5 mm
2 layers333.4 × 149.9 mm
Omega Mainboard
skiselev/omega459Omega Home Computer
- Size
- 333.4 × 149.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 248
- Nets
- 407
- Pads
- 1,663
- Tracks, vias
- 6,484, 208
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 18 Jan 2019
- Updated
- 3 Mar 2026
Overview
Omega Mainboard is an open-source printed circuit board by skiselev, from the skiselev/omega repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 333.4 × 149.9 mm with 248 parts on 407 nets, routed with 6,484 tracks and 208 vias.
It is built around the 74F541PC, 74F245D and 74AHCT125D, with the 74HCT540D, 74AHCT32D and 74HCT74D among its other parts. Its parts include 94 capacitors, 48 resistors, 42 ICs, 7 connectors and 3 inductors. It belongs with the computers and single-board computers boards and the FPGA and CPLD boards of this library.
Main components
12
74F541PC
PDIP-200℃~+70℃ 1 3mA 4.5V~5.5V 64mA 74F 8 Output enable Tri-State PDIP-20 Buffers, Drivers, Receivers, Transceivers ROHSonsemiBuffers, Drivers, Receivers, Transceivers
74F245D
SOIC-20-300mil0℃~+70℃ 15mA 4.5V~5.5V 4ns@5V,50pF 64mA 74F Bidirectional Tri-State SOIC-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNXP SemiconductorsBuffers, Drivers, Receivers, Transceivers
74AHCT125D
SOP-14-40℃~+125℃ 1 4 4.3ns@5V,50pF 4.5V~5.5V 40uA 74AHCT 8mA 8mA Schmitt trigger Tri-State Unidirectional SOP-14 Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffer/Driver/Transceiver74HCT540D
SO-20-300mil-40℃~+125℃ 1 13ns@4.5V,50pF 160uA 4.5V~5.5V 6mA 6mA 74HCT 8 Tri-State Unidirectional SO-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffer/Driver/Transceiver74AHCT32D
SO-14-40℃~+125℃ 2V 2uA 4 4.5V~5.5V 7.9ns@5V,50pF 74AHCT Series 800mV 8mA 8mA OR Gate SO-14 Logic Gates ROHSNexperiaGates74HCT74D
SOIC-14-40℃~+125℃ 1 2 3.5pF 3ns 4.5V~5.5V 40uA 44ns@4.5V,50pF 4mA 4mA 59MHz 5ns 74HCT Series Asynchronous Complementary D-Type Rising Edge Set and Reset SO-14 Flip Flops ROHSNexperia74 Series
74HCT153D
SO-16-40℃~+125℃ 16ns@5.0V,15pF 4.5V~5.5V 4mA 4mA 74HCT 8uA Single Supply SO-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches / Encoders & Decoders / Multiplexers74HCT157D
SO-16-40℃~+125℃ 160uA 16ns@4.5V,50pF 4.5V~5.5V 4mA 4mA 74HCT 8/4 Multiplexer Single Supply SOIC-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches, Multiplexers, Decoders74HCT273D
SOIC-20-300mil-40℃~+125℃ 12ns 3.5pF 30ns@4.5V,50pF 36MHz 3ns 4.5V~5.5V 4mA 5.2mA 74HCT Series 8 8uA D-Type Reset Rising Edge SOIC-20-300mil Flip Flops ROHSNexperiaFlip Flops74HCT30D
SO-14-40℃~+125℃ 1 28ns@4.5V,50pF 2V 2uA 4.5V~5.5V 4mA 4mA 74HCT Series 800mV NAND Gate SO-14 Logic Gates ROHSNexperiaLogic Gates74AHCT02D
SO-14-40℃~+125℃ 100mV、550mV 2 2V 2uA 3.94V、4.4V 4 4.5V~5.5V 7.5ns@5V,50pF 74AHCT Series 800mV 8mA 8mA NOR Gate Overvoltage-tolerant input SO-14 Logic Gates ROHSNexperiaLogic Gates74AHCT138D
SO-16-40℃~+125℃ 3/8 4.5V~5.5V 6.2ns@5V,50pF 74AHCT 80uA 8mA 8mA Decoder Single Supply SO-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches, Multiplexers, Decoders
README
README.mdOmega
Omega Home Computer
Introduction
This project is an open source implementation of an MSX2 compatible computer. The project is built using a combination of 1980's era components - Z80 CPU, V9958 VDP, AY-3-8910/YM2149F PSG, 8255 PPI, 7400-series logic, and some newer components, such as 512 KiB SRAM and 512 KiB Flash ROM and a few simple programmable logic devices (ATF16V8B SPLDs).
Status
- The project is completed, tested and works properly
- It is recommended to use the latest revision of the PCBs
Documentation
Parts
248| Qty | Value | Footprint | References |
|---|---|---|---|
| 58 | 0.1uF | My_Components:Cap_Cer_508 | C1, C2, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23 +42 |
| 11 | HOLE | My_Components:Hole_3mm | HOLE1, HOLE2, HOLE3, HOLE4, HOLE5, HOLE6, HOLE7, HOLE8, HOLE9, HOLE10, HOLE11 |
| 7 | 10uF | My_Components:Cap_Elec_Radial_5mm | C71, C72, C73, C74, C75, C76, C77 |
| 7 | 1k | My_Components:Res_762 | R27, R28, R29, R30, R31, R32, R33 |
| 7 | 4.7k | My_Components:Res_762 | R16, R17, R18, R19, R20, R21, R22 |
| 6 | 100 | My_Components:Res_762 | R37, R38, R39, R40, R41, R42 |
| 6 | 220uF | My_Components:Cap_Elec_Radial_10mm | C59, C60, C61, C62, C63, C64 |
| 6 | 75 | My_Components:Res_762 | R43, R44, R45, R46, R47, R48 |
| 4 | 10k | My_Components:Res_762 | R11, R12, R13, R14 |
| 4 | 10k | My_Components:Conn_SIL10 | RR1, RR2, RR3, RR4 |
| 4 | 74HCT670 | My_Components:IC_DIP16_300 | U15, U16, U17, U18 |
| 4 | D41464 | My_Components:IC_DIP18_300 | U8, U9, U10, U11 |
| 3 | 100uF | My_Components:Cap_Elec_Radial_6.3mm | C65, C66, C67 |
| 3 | 10uF | My_Components:Cap_Pol_508_3 | C68, C69, C70 |
| 3 | 30pF | My_Components:C_Trim_Murata | C88, C89, C90 |
| 3 | 330pF | My_Components:Cap_Cer_508 | C82, C83, C84 |
| 3 | 4.7k | My_Components:Conn_SIL10 | RR5, RR6, RR7 |
| 3 | 74AHCT32 | My_Components:IC_DIP14_300 | U37, U38, U39 |
| 3 | 74F541 | My_Components:IC_DIP20_300 | U19, U20, U21 |
| 3 | 74HCT74 | My_Components:IC_DIP14_300 | U34, U35, U36 |
| 3 | ATF16V8B | My_Components:IC_DIP20_300 | U12, U13, U14 |
| 2 | 100k | My_Components:Res_762 | R5, R6 |
| 2 | 2.2k | My_Components:Res_762 | R25, R26 |
| 2 | 2.7k | My_Components:Res_762 | R23, R24 |
| 2 | 20k | My_Components:Res_762 | R9, R10 |
| 2 | 22nF | My_Components:Cap_Cer_508 | C79, C80 |
| 2 | 22pF | My_Components:Cap_Cer_508 | C92, C93 |
| 2 | 33pF | My_Components:Cap_Cer_508 | C86, C87 |
| 2 | 4.7k | My_Components:Conn_SIL6 | RR8, RR10 |
| 2 | 470k | My_Components:Res_762 | R2, R3 |
| 2 | 47k | My_Components:Res_762 | R7, R8 |
| 2 | 5.6uH | My_Components:Res_762 | L2, L3 |
| 2 | 74F245 | My_Components:IC_DIP20_300 | U25, U26 |
| 2 | 74HCT153 | My_Components:IC_DIP16_300 | U30, U31 |
| 2 | 74HCT157 | My_Components:IC_DIP16_300 | U28, U29 |
| 2 | 74HCT273 | My_Components:IC_DIP20_300 | U23, U24 |
| 2 | 74HCT30 | My_Components:IC_DIP14_300 | U40, U41 |
| 2 | MSX_SLOT_HOST | My_Components:Conn_Edge_50P | SLOT1, SLOT2 |
| 2 | NTSC/PAL | My_Components:Conn_Pin_Header_3x1_2.54mm | JP5, JP6 |
| 2 | PN2907A | My_Components:Transistor_TO92_EBC_254 | Q1, Q2 |
| 2 | RAM_SIZE | My_Components:Conn_Pin_Header_2x3_2.54mm | JP7, JP8 |
| 2 | V9938/V9958 | My_Components:Conn_Pin_Header_3x1_2.54mm | JP3, JP4 |
| 1 | 1.5nF | My_Components:Cap_Cer_508 | C81 |
| 1 | 120 | My_Components:Res_762 | R36 |
| 1 | 180 | My_Components:Res_762 | R35 |
| 1 | 1M | My_Components:Res_762 | R1 |
| 1 | 1N4148 | My_Components:Diode_762 | D1 |
| 1 | 1uF | My_Components:Cap_Elec_Radial_5mm | C78 |
| 1 | 21.477270MHz | My_Components:Crystal_HC-49U_Vert | Y1 |
| 1 | 220k | My_Components:Res_762 | R4 |
| 1 | 27pF | My_Components:Cap_Cer_508 | C91 |
| 1 | 32768 Hz | My_Components:Crystal_32K_Horiz | Y2 |
| 1 | 4.433618MHz | My_Components:Crystal_HC-49U_Vert | Y3 |
| 1 | 4.7pF | My_Components:Cap_Cer_508 | C94 |
| 1 | 470 | My_Components:Res_762 | R34 |
| 1 | 470 | My_Components:Conn_SIL6 | RR9 |
| 1 | 47pF | My_Components:Cap_Cer_508 | C85 |
| 1 | 5.6k | My_Components:Res_762 | R15 |
| 1 | 5V | My_Components:Conn_Power_Jack_Circular_Pads | J1 |
| 1 | 68uH | My_Components:Res_762 | L1 |
| 1 | 74AHCT02 | My_Components:IC_DIP14_300 | U44 |
| 1 | 74AHCT125 | My_Components:IC_DIP14_300 | U33 |
| 1 | 74AHCT138 | My_Components:IC_DIP16_300 | U32 |
| 1 | 74HCT00 | My_Components:IC_DIP14_300 | U45 |
| 1 | 74HCT04 | My_Components:IC_DIP14_300 | U43 |
| 1 | 74HCT175 | My_Components:IC_DIP16_300 | U27 |
| 1 | 74HCT540 | My_Components:IC_DIP20_300 | U22 |
| 1 | 74LS07 | My_Components:IC_DIP14_300 | U42 |
| 1 | 750mA | My_Components:Cap_Cer_508 | F1 |
| 1 | 82C55 | My_Components:IC_DIP40_600 | U2 |
| 1 | ADM691A | My_Components:IC_DIP16_300 | U46 |
| 1 | AS6C4008 | My_Components:IC_DIP32_600 | U7 |
| 1 | Audio | My_Components:Conn_RCA_Right | J3 |
| 1 | CBUS | My_Components:Conn_Pin_Header_13x1_2.54mm | J14 |
| 1 | CR2032 | My_Components:Battery_Holder_CR2032_Universal | BT1 |
| 1 | CXA1645 | My_Components:IC_DIP24_400 | U47 |
| 1 | Cassette | My_Components:Conn_DIN_8pin | J6 |
| 1 | Composite | My_Components:Conn_RCA_Right | J2 |
| 1 | JOYSTICK_A | My_Components:Conn_Dsub_DE9M | J7 |
| 1 | JOYSTICK_B | My_Components:Conn_Dsub_DE9M | J8 |
The 231 most common of 248 parts.
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Questions
How big is the Omega Mainboard PCB?
It measures 333.4 × 149.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Omega Mainboard use?
248 parts, built around the 74F541PC, 74F245D, 74AHCT125D and 74HCT540D. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Omega Mainboard KiCad files?
From the skiselev/omega repository on GitHub, at the commit this page was made from: the board is Mainboard/KiCad/Omega-Mainboard.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Omega Mainboard design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).