Main control
About the Main control PCB
Main control is an open source PCB design by tmarhguy, published on GitHub under the MIT license. It is a 2-layer board measuring 59 × 63 mm, with 42 components from 5 distinct parts.
Other key parts include the 74HC157. By type, the board carries 26 transistors, 14 ICs and 2 connectors.
From the project
8-bit combinational ALU built from scratch with 3,488 CMOS transistors (KiCad + SPICE + Logisim + 1.24M tests
5-bit opcode decoder generating internal control signals
Decode FUNC[4:0] opcode into internal control signals for ALU operation.
See docs/OPCODE_TABLE.md for complete table.
Outputs: - M - ADD/SUB mode - MUXSEL - Arithmetic(0) / Logic(1) - INVOUT - Global inversion enable - LOGIC_SEL[2:0] - Logic operation select
Combinational decode logic - no clock required
Main components on the Main control
Main control bill of materials (BOM)
42 components, 5 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 14 | 74HC157 | SOIC-16_3.9x9.9mm_P1.27mm | U201, U202, U203, U204, U205, U206, U301, U302 +6 |
| 13 | NMOS | TSOT-23 | Q401, Q404, Q406, Q501, Q504, Q506, Q602, Q802 +5 |
| 13 | PMOS | TSOT-23 | Q402, Q403, Q405, Q502, Q503, Q505, Q601, Q801 +5 |
| 1 | Conn_01x34_Pin | Harwin_Gecko-G125-FVX3405L0X_2x17_P1.25mm_Vertical | J101 |
| 1 | Conn_01x12_Socket | Harwin_Gecko-G125-FVX1205L0X_2x06_P1.25mm_Vertical | J102 |
Main control design files
The KiCad project lives in the tmarhguy/alu repository on GitHub; these links point at the commit this page was built from.
Main control: common questions
How big is the Main control PCB?
The Main control measures 59 × 63 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Main control?
42 components, from 5 distinct parts. The full bill of materials is listed on this page.
Where can I download the Main control design files?
From the tmarhguy/alu repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Main control design in my own project?
Yes, under the terms of its MIT license, which tmarhguy chose for the repository.
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