6 layers244 × 244 mm
Retroslop
CPTforever/8088-MicroATX-Computer
A 8088 based, IBM 5150 like computer compatible with the MicroATX motherboard form factor.
193 parts
4 layers243.8 × 170.2 mm
A Z80 computer with protected mode support
- Size
- 243.8 × 170.2 mm
- Copper layers
- 4
- Thickness
- 1.33 mm
- Parts
- 126
- Nets
- 272
- Pads
- 1,328
- Tracks, vias
- 4,879, 442
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 6 Mar 2024
- Updated
- 2 Nov 2025
Overview
HEC1 is an open-source printed circuit board by Andy18650, from the Andy18650/HEC-Model-Z1 repository on GitHub, published under the GPL-3.0 licence. It is a 4-layer board of 243.8 × 170.2 mm with 126 parts on 272 nets, routed with 4,879 tracks and 442 vias.
It is built around the 74LS245SC, ITX0512S and 74LS32SC, with the 74LS74PC, 74LS574N and 74LS02PC among its other parts. Its parts include 44 ICs, 36 capacitors, 9 connectors, 4 resistors and 2 switches.
Main components
1274LS245SC
-0℃~+70℃ 12ns@5V,45pF 15mA 24mA 4.75V~5.25V 74LS 8 Bidirectional Output enable Schmitt trigger Tri-State - Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, TransceiversITX0512S
SIP,21.9x9.2mm1.5kV 12V 2 250mA 4.5V~9V 6W 84% SIP,21.9x9.2mm Isolated Power Modules ROHSXP PowerIsolated Power Modules
74LS32SC
-- Logic Gates ROHSTexas InstrumentsLogic Gates
74LS74PC
DIP-140ns 0℃~+70℃ 1 2 20MHz 3.5pF 35ns@5V,50pF 4.5ns 4.75V~5.25V 400uA 74LS Series 8mA 8mA Asynchronous Complementary D-Type Rising Edge Set and Reset DIP-14 Flip FlopsTexas InstrumentsFlip Flops74LS574N
-0ns 0℃~+70℃ 1 2.6mA 20ns 24mA 28ns@5V,45pF 35MHz 4.75V~5.25V 74LS Series 8 D-Type Rising Edge Tri-State - Flip Flops ROHSRochester Electronics, LLCFlip Flops74LS02PC
DIP-140℃~+70℃ 15ns@5V,15pF 2 2.7V 2V 4 4.75V~5.25V 400uA 500mV 74LS 800mV 8mA 8mA NOR Gate DIP-14 Logic Gates ROHSonsemiLogic Gates74LS20P-E
DIP-14-20℃~+75℃ 15ns@5V,15pF 2 2.7V 2V 4 4.75V~5.25V 400mV、500mV 400uA 74LS 800mV 8mA NAND Gate DIP-14 Logic Gates ROHSRenesas ElectronicsLogic Gates74LS30PC
PDIP-140℃~+70℃ 1 1.1mA 18ns@5V,50pF、20ns@5V,50pF 2.7V 2V 4.75V~5.25V 400uA 500mV 74LS Series 8 800mV 8mA NAND Gate PDIP-14 Logic GatesTexas InstrumentsLogic Gates
AS6C4008-55PCN
PDIP-320℃~+70℃ 2.7V~5.5V 30mA 4Mbit 4uA 55ns Parallel Port (Parallel) PDIP-32 SRAM ROHSAlliance MemorySRAM
74LS00SC
-0℃~+70℃ 15ns@5V,50pF 2 2.7V 2V 4 4.75V~5.25V 400uA 500mV 74LS 800mV 8mA NAND Gate - Logic Gates ROHSTexas InstrumentsLogic Gates74LS04PC
PDIP-140℃~+70℃ 4.75V~5.25V 6 6.6mA 74LS PDIP-14 InvertersonsemiInverters74LS393P-E
DIP-14-20℃~+75℃ 2 35MHz 4 4.75V~5.25V 400mW 40ns@5V,15pF 74LS Binary Counter Reset function DIP-14 Counters, Dividers ROHSRenesas ElectronicsCounters, Dividers
README
README.mdHEC Model Z1
A Z80 computer with protected mode support This repository is currently for my own use and for the public to track the progress of the project. It is not meant to be used to produce a working computer befor first beta revision is announced. Any part of this repository may change without notice.
Parts
126| Qty | Value | Footprint | References |
|---|---|---|---|
| 25 | C | Capacitor_THT:C_Disc_D7.0mm_W2.5mm_P5.00mm | C1, C2, C13, C14, C15, C16, C17, C18, C19, C20, C22, C23, C24, C25, C26, C27 +9 |
| 6 | C_Polarized | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C12, C21, C30, C33, C34, C35 |
| 6 | MountingHole_Pad | MountingHole:MountingHole_3.2mm_M3_Pad_Via | H1, H2, H3, H4, H5, H6 |
| 6 | R_Network04 | Resistor_THT:R_Array_SIP5 | RN2, RN5, RN6, RN7, RN8, RN9 |
| 5 | 74LS32 | Library:DIP-14_W7.62mm_Socket_ThinPads | U10, U15, U16, U31, U37 |
| 5 | 74LS74 | Library:DIP-14_W7.62mm_Socket_ThinPads | U23, U24, U27, U29, U30 |
| 4 | 74LS574 | Library:DIP-20_W7.62mm_Socket_ThinPads | U9, U20, U21, U36 |
| 4 | MountingHole | MountingHole:MountingHole_3.2mm_M3 | H7, H8, H9, H10 |
| 4 | R | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R2, R3, R4 |
| 3 | 74LS138 | Library:DIP-16_W7.62mm_Socket_ThinPads | U6, U8, U18 |
| 3 | 74LS541 | Library:DIP-20_W7.62mm_Socket_ThinPads | U25, U26, U44 |
| 3 | C_Polarized | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C9, C10, C11 |
| 2 | 74LS02 | Library:DIP-14_W7.62mm_Socket_ThinPads | U22, U41 |
| 2 | 74LS20 | Library:DIP-14_W7.62mm_Socket_ThinPads | U17, U33 |
| 2 | 74LS245 | Library:DIP-20_W7.62mm_Socket_ThinPads | U13, U14 |
| 2 | 74LS30 | Library:DIP-14_W7.62mm_Socket_ThinPads | U19, U28 |
| 2 | 74LS47 | Library:DIP-16_W7.62mm_Socket_ThinPads | U38, U39 |
| 2 | AS6C4008-55PCN | Library:DIP-32_W15.24mm_Socket_ThinPads | U2, U3 |
| 2 | C | Capacitor_THT:C_Disc_D3.4mm_W2.1mm_P2.50mm | C31, C32 |
| 2 | CY7C199 | Library:DIP-28_W7.62mm_Socket_ThinPads | U4, U5 |
| 2 | R_Pack07 | Package_DIP:DIP-14_W7.62mm | RN3, RN4 |
| 2 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1, JP2 |
| 2 | ~ | Library:Bus_HEC_5Vonly | BUS3, BUS4 |
| 2 | ~ | Library:Bus_HEC | BUS1, BUS2 |
| 1 | 28C256 | Library:DIP-28_W15.24mm_Socket_ThinPads | U7 |
| 1 | 74LS00 | Library:DIP-14_W7.62mm_Socket_ThinPads | U11 |
| 1 | 74LS04 | Library:DIP-14_W7.62mm_Socket_ThinPads | U12 |
| 1 | 74LS06 | Library:DIP-14_W7.62mm_Socket_ThinPads | U42 |
| 1 | 74LS08 | Library:DIP-14_W7.62mm_Socket_ThinPads | U35 |
| 1 | 74LS393 | Library:DIP-14_W7.62mm_Socket_ThinPads | U34 |
| 1 | AudioJack3 | Connector_Audio:Jack_3.5mm_CUI_SJ1-3533NG_Horizontal | J7 |
| 1 | Barrel_Jack_Switch | Connector_BarrelJack:BarrelJack_Kycon_KLDX-0202-xC_Horizontal | J1 |
| 1 | CXO_DIP8 | Oscillator:Oscillator_DIP-8 | X1 |
| 1 | Conn_02x05_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x05_P2.54mm_Vertical | J3 |
| 1 | Conn_02x12_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x12_P2.54mm_Vertical | J2 |
| 1 | Conn_02x14_Odd_Even | Connector_PinHeader_2.54mm:PinHeader_2x14_P2.54mm_Vertical | J9 |
| 1 | Crystal | Crystal:Crystal_HC18-U_Vertical | Y1 |
| 1 | DA04-11EWA | Display_7Segment:DA04-11SURKWA | U40 |
| 1 | DE9_Plug_MountingHoles | Connector_Dsub:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset4.94mm_Housed_MountingHolesOffset7.48mm | J6 |
| 1 | ITX0512S | Converter_DCDC:Converter_DCDC_XP_POWER-ITxxxxxS_THT | PS1 |
| 1 | LED | LED_THT:LED_D3.0mm | D1 |
| 1 | LM79M05_TO220 | Package_TO_SOT_THT:TO-220-3_Vertical | U32 |
| 1 | NES_Port_Male | Library:NES_Port_Male_Horizontal | J8 |
| 1 | R_Network08 | Resistor_THT:R_Array_SIP9 | RN1 |
| 1 | SW_DIP_x04 | Button_Switch_THT:SW_DIP_SPSTx04_Slide_9.78x12.34mm_W7.62mm_P2.54mm | SW1 |
| 1 | SW_Push | Button_Switch_THT:SW_PUSH_6mm | SW2 |
| 1 | Screw_Terminal_01x02 | TerminalBlock_MetzConnect:TerminalBlock_MetzConnect_Type073_RT02602HBLU_1x02_P5.08mm_Horizontal | J5 |
| 1 | Z80CPU | Library:DIP-40_W15.24mm_Socket_ThinPads | U1 |
| 1 | ~ | Library:DIP-40_W15.24mm_Socket_ThinPads | U43 |
| 1 | ~ | Library:Connector_double_mini-DIN_6 | J4 |
The 124 most common of 126 parts.
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Questions
How big is the HEC1 PCB?
It measures 243.8 × 170.2 mm and has 4 copper layers, 1.33 mm thick.
What parts does the HEC1 use?
126 parts, built around the 74LS245SC, ITX0512S, 74LS32SC and 74LS74PC. 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 HEC1 KiCad files?
From the Andy18650/HEC-Model-Z1 repository on GitHub, at the commit this page was made from: the board is KiCad/HEC1.kicad_pcb and its schematic KiCad/HEC1.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the HEC1 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).