
Instruction decoder
ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system
Clock is an open-source printed circuit board by ifilot, from the ifilot/sap-smd repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 2-layer board of 101.6 × 55.9 mm with 72 parts on 102 nets, routed with 1,151 tracks and 78 vias.
It is built around the 74HC00D, 74HC193D and 74HC02, with the 74HC14, 74HC151D and SWS1 among its other parts. Its parts include 20 capacitors, 13 resistors, 12 ICs, 11 diodes and 8 switches. It belongs with the retro computing and games and lEDs and displays boards of this library.
This project showcases the design and construction of a modular 8-bit computer built with TTL logic units. The core principle behind the project is to create a "Simple as Possible" system, focusing on simplicity, modularity, and compactness.

The project aims to:
SMD components offer several advantages:
This project is ideal for:
docs directory.Contributions to this project are welcome! If you have ideas for improvements, additional features, or alternative designs, feel free to fork the repository and submit a pull request.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 15 | 0.1uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C3, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20 |
| 6 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R4, R5, R6, R10, R11 |
| 4 | 330 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R7, R9, R12, R13 |
| 4 | 74HC00 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | U2, U5, U8, U11 |
| 3 | 74HC193 | Package_SO:SO-16_3.9x9.9mm_P1.27mm | U7, U10, U12 |
| 2 | 0.01uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C6 |
| 2 | 10k | Resistor_SMD:R_Array_Convex_4x0603 | RN1, RN3 |
| 2 | 1k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R2, R3 |
| 2 | 220 | Resistor_SMD:R_Array_Convex_4x0603 | RN2, RN4 |
| 2 | SE555 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U1, U9 |
| 1 | .1uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4 |
| 1 | 15pF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2 |
| 1 | 1M | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R8 |
| 1 | 1M | Potentiometer_THT:Potentiometer_ACP_CA9-V10_Vertical | RV1 |
| 1 | 1uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C5 |
| 1 | 74HC02 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | U6 |
| 1 | 74HC14 | Package_SO:SO-14_3.9x8.65mm_P1.27mm | U3 |
| 1 | 74HC151 | Package_SO:SO-16_3.9x9.9mm_P1.27mm | U4 |
| 1 | CD0 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D6 |
| 1 | CD1 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D7 |
| 1 | CD2 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D8 |
| 1 | CD3 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D9 |
| 1 | CLEAR | Button_Switch_THT:SW_PUSH_6mm | SW7 |
| 1 | CLK | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1 |
| 1 | Clock Divider | Button_Switch_SMD:SW_DIP_SPSTx04_Slide_6.7x11.72mm_W8.61mm_P2.54mm_LowProfile | SW2 |
| 1 | HALT | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D11 |
| 1 | MANCLK | Button_Switch_THT:SW_PUSH-12mm_Wuerth-430476085716 | SW4 |
| 1 | MANHALT | custom_tactile_button:tactile_button | SW8 |
| 1 | MANHALT | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D10 |
| 1 | Reset Counter | Button_Switch_SMD:SW_DIP_SPSTx04_Slide_6.7x11.72mm_W8.61mm_P2.54mm_LowProfile | SW6 |
| 1 | S0 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D2 |
| 1 | S1 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D3 |
| 1 | S2 | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D4 |
| 1 | SIGNALS | Connector_PinHeader_2.54mm:PinHeader_1x10_P2.54mm_Vertical | J1 |
| 1 | SWS0 | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | SWS1 | Button_Switch_THT:SW_PUSH_6mm | SW3 |
| 1 | SWS2 | Button_Switch_THT:SW_PUSH_6mm | SW5 |
| 1 | TCXO-14 | Oscillator:Oscillator_DIP-14 | X1 |
| 1 | X | Connector_PinHeader_2.54mm:PinHeader_1x10_P2.54mm_Vertical | J2 |
| 1 | ~{CLR} | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D5 |
It measures 101.6 × 55.9 mm and has 2 copper layers, 1.6 mm thick.
72 parts, built around the 74HC00D, 74HC193D, 74HC02 and 74HC14. 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.
From the ifilot/sap-smd repository on GitHub, at the commit this page was made from: the board is pcb/components/clock/clock.kicad_pcb and its schematic pcb/backplates/bp-leanplate/bp-leanplate.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system

ifilot/sap-smd
Modular 8-bit computer built with TTL logic units to create a "Simple as Possible" system




slu4coder/Minimal-64x4-Home-Computer
My DIY TTL home computer with VGA and PS/2 and 4x the processing power of a Commodore C64 or Apple II.

slu4coder/Minimal-UART-Computer-1-2
Legacy: Version 1 and 2 of my TTL-only CPU featuring UART I/O, an expansion port, 512KB SSD at up to 10MHz clock speed


