4 layers56.1 × 57.1 mm
MCL86jr
MicroCoreLabs/Projects
Ted Fried's MicroCore Labs Projects - FPGA CPU cores and emulators for the 8088, 8086, 8051, 6502, 68000, Z80, Risc-V, and also Typewriter and EPROM Emulator projects.
66 parts534
4 layers31.6 × 84.1 mm
Ted Fried's MicroCore Labs Projects - FPGA CPU cores and emulators for the 8088, 8086, 8051, 6502, 68000, Z80, Risc-V, and also Typewriter and EPROM Emulator projects. MCL51, MCL64, MCL65, MCL65+, MCL68, MCL86, MCL86+, MCL86jr, MCLR5, MCLZ8, MCL6809, XTMax, MCL8080+
- Size
- 31.6 × 84.1 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 13
- Nets
- 107
- Pads
- 306
- Tracks, vias
- 1,554, 115
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 11 Aug 2019
- Updated
- 28 Aug 2026
Overview
MCL68 is an open-source printed circuit board by MicroCoreLabs, from the MicroCoreLabs/Projects repository on GitHub. It is a 4-layer board of 31.6 × 84.1 mm with 13 parts on 107 nets, routed with 1,554 tracks and 115 vias.
It is built around the 74HCT541D, TEENSY 4.1 and 74HCT574D, with the 74LS257PC among its other parts. Its parts include 12 ICs and 1 capacitor. It belongs with the retro computing and games boards and the NXP (LPC, Kinetis, i.MX RT) boards of this library.
Main components
4
74HCT541D
SO-20-40℃~+125℃ 1 15ns@4.5V,50pF 160uA 4.5V~5.5V 6mA 6mA 74HCT 8 Tri-State Unidirectional SO-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
TEENSY 4.1
Development Boards & Kits - ARM ModuleSparkFun ElectronicsUncategorised74HCT574D
SO-20-300mil-40℃~+125℃ 1 18ns@4.5V,50pF 3.5pF 3ns 4.5V~5.5V 5ns 69MHz 6mA 6mA 74HCT Series 8 8uA D-Type Rising Edge Tri-State SOIC-20-300mil Flip Flops ROHSNexperiaFlip Flops
74LS257PC
DIP-160℃~+70℃ 12mA 2.6mA 24mA 27ns@5V,150pF 4.75V~5.25V 74LS Output enable high-impedance、Tri-state output DIP-16 Signal Switches, Multiplexers, DecodersTexas InstrumentsSignal Switches, Multiplexers, Decoders
README
README.mdTed Fried's MicroCore Labs Projects
My blog which has some details on these projects: www.MicroCoreLabs.Wordpress.com
My YouTube Channel with some videos of the stuff in action: www.youtube.com/channel/UC9B3TaEUon-araO2j7tp9jg/videos
Boards:
MCL6809 - Motorola 6809E emulator which runs on a Teensy 4.1 and can be used as a drop-in replacment
MCLZ8 - Zilog Z80 emulator which runs on a Teensy 4.1 and can be used as a drop-in replacment
MCL86+ - Intel 8088 emulator which runs on a Teensy 4.1 and can be used as a drop-in replacment
MCL86jr - IBMPCjr Accelerator which boosts performance to IBM PC/AT speed
MCL65+ - MOS 6502 emulator which runs on a Teensy 4.1 and can be used as a 6502 drop-in replacment
MCL64 - MOS 6510 emulator which runs on a Teensy 4.1 and can be used as a drop-in replacment in the Commodore 64
MCL68+ - Motorola 68000 emulator which runs on a Teensy 4.1 and can be used as a drop-in replacment
MCLV20_Max - NEC V20 drop-in replacment CPU which uses the MCL86+ board
MCL8080+ - Intel 8080 emulator which runs on an ATTiny85 and has a SPI interface as the local busEmulated Processors:
MCL68 - Motorola 68000 Emulator written in C
RISCV - Simple and compact RISC-V RS32I implementation written in C
MCL65 - MOS 6502 written in CMicrosequencer-based processors:
MCL65 - MOS 6502
MCL51 - Intel 8051
MCL86 - Intel 8086/8088Other processors:
MCLR5 - Quad-Issue Superscalar RISCV
Lockstep Quad Modular Redundant System Misc:
Wheelwriter - FPGA based Printer Option for the IBM Wheelwriter 5
Wheelwriter2 - Arduino Leonardo based Printer Option for the IBM Wheelwriter 5
Brother Typewriter - Arduino Leonardo converts Serial RX to a Brother Word Processor
EPROM Emulator - Small PCB which uses Teensy 4.0 to emulate up a 64KB 27C512 EPROM
MCL64_Tester - Extensive, menu-based, tests for the Commodore 64 motherboard
MCLZ8 TRS-80 Emulator - Emulates a TRS-80 Model 1 inside of a Teensy microcontroller board
MCL_TRS_NABU - Emulates a TRS-80 Model 1 using the MCLZ8 which runs inside of a NABU Personal Computer
Turbo NABU - Uses the MCLZ8 to run simple C code on the Teensy to control the motherboard resources of the NABU Computer
MDA Video - Project which uses an Arty Z7-20 SOC FPGA board to diaplay BMP images to an MDA display
IBMPC_68000 - Uses the MCL86+ board to emulate a Motorola 68000 which runs inside of an IBM PC as-if they selected this processor in 1981
MCL65_Apple1 - Converts an Apple II into an Appke 1 by emulating the BIOS PROMs, system memory, and performing some I/O conversion
XTMax - 8-bit ISA card containing a Teensy 4.1 which can emulate RAM, ROM, and peripherals
For questions email me at www.MicroCoreLabs.com
Parts
13| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 74HCT574 | Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm | U2, U6, U7, U9, U10 |
| 3 | 74HCT541 | Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm | U4, U11, U12 |
| 2 | 74LS257 | Package_SO:TSSOP-16_4.4x5mm_P0.65mm | U3, U8 |
| 1 | 10 uF | Capacitor_SMD:C_0805_2012Metric | C1 |
| 1 | 68000D | Package_DIP:DIP-64_W25.4mm | U1 |
| 1 | Teensy4.1 | Package_DIP:DIP-48_W15.24mm | U5 |
Questions
How big is the MCL68 PCB?
It measures 31.6 × 84.1 mm and has 4 copper layers, 1.6 mm thick.
What parts does the MCL68 use?
13 parts, built around the 74HCT541D, TEENSY 4.1, 74HCT574D and 74LS257PC. 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 MCL68 KiCad files?
From the MicroCoreLabs/Projects repository on GitHub, at the commit this page was made from: the board is MCL68+/PCB/MCL68.kicad_pcb and its schematic MCL68+/PCB/MCL68.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the MCL68 design in my own project?
Its repository states no licence, so its author keeps all rights: ask MicroCoreLabs before reusing the design.
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