2 layers218 × 125 mm
EVA1
roberto314/EVA-1_Reproduction
Recreation of the very rare K-K Systems EVA-1 Display Adapter for the Epson HX-20 Computer
126 parts
2 layers218 × 125 mm
Recreation of the very rare K-K Systems EVA-1 Display Adapter for the Epson HX-20 Computer
- Size
- 218 × 125 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 160
- Nets
- 303
- Pads
- 1,034
- Tracks, vias
- 4,143, 470
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 19 Apr 2025
- Updated
- 19 Dec 2025
Overview
EVA1 v2 is an open-source printed circuit board by roberto314, from the roberto314/EVA-1_Reproduction repository on GitHub. It is a 2-layer board of 218 × 125 mm with 160 parts on 303 nets, routed with 4,143 tracks and 470 vias.
It is built around the 74HCT245, MAX232N and 27C256-17/J, with the 74HCT74D, 74HCT165D and 74LS573PC among its other parts. Its parts include 46 capacitors, 38 ICs, 34 resistors, 13 connectors and 3 diodes. It belongs with the lEDs and displays and interfaces and adapters boards and the RP2040, AVR (ATmega, ATtiny) and FPGA and CPLD boards of this library.
Main components
12
74HCT245
DIP-20-40℃~+85℃ 28ns@4.5V 4.5V~5.5V 6mA 6mA 74HCT 8 8uA Bidirectional TTL-compatible CMOS Tri-State DIP-20 Buffers, Drivers, Receivers, Transceivers ROHSWuxi I-core Elec74 Series
MAX232N
PDIP-160℃~+70℃ 120Kbps 2 2 4.5V~5.5V Transceiver PDIP-16 RS232 ICs ROHSTexas InstrumentsRS232 ICs27C256-17/J
-0℃~+70℃ 256Kbit 4.5V~5.5V EPROM Parallel Port (Parallel) - Non-Volatile Memory (ROM)Microchip TechnologyNon-Volatile Memory (ROM)
74HCT74D
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
74HCT165D
SOIC-16-40℃~+125℃ 1 34ns@4.5V,50pF 4.5V~5.5V 44MHz 500mW 74HCT 8 Parallel or Serial to Serial SOIC-16 Shift Registers ROHSNexperiaShift Registers
74LS573PC
DIP-200℃~+70℃ 10ns 3ns 4.75V~5.25V 74LS 8 D Latch Tri-State DIP-20 Latches ROHSTexas InstrumentsLatches74LVC08AD
SOP-14-40℃~+125℃ 1.08V、1.7V、2V 1.2V、1.9V、2.2V、2.4V、3.8V 1.65V~5.5V 100mV、300mV、400mV、450mV、550mV 120mV、700mV、800mV 2 4 5ns@4.5V,15pF 74LVC AND Gate Schmitt trigger SOP-14 Logic Gates ROHSMDDLogic Gates74HCT08D
SOP-14-40℃~+125℃ 100mV、330mV 16ns@4.5V,15pF 2 2V 3.84V、4.4V 4 4.5V~5.5V 74HCT 800mV AND Gate TTL compatible CMOS SOP-14 Logic Gates ROHSMDDLogic Gates74HCT14D
SOP-14-40℃~+125℃ 1 1.9V~2.1V 2uA 34ns@4.5V,50pF 4.4V 4.5V~5.5V 400mV 4mA 4mA 500mV~600mV 6 74HCT Schmitt trigger SOIC-14 Inverters ROHSNexperiaInverters74HCT32D
SO-14-40℃~+125℃ 2 24ns@4.5V,50pF 2V 2uA 3.7V、4.4V 4 4.5V~5.5V 400mV 4mA 4mA 74HCT Series 800mV OR Gate SOIC-14 Logic Gates ROHSNexperiaGates74HCT86D
SO-14-40℃~+125℃ 2 2V 2uA 3.98V、4.4V 32ns@4.5V,50pF 4 4.5V~5.5V 400mV 4mA 4mA 74HCT Series 800mV XOR Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates74LS221FP-E
-Reset input、Adjustable pulse width、Dual edge triggering - Monostable Multivibrators ROHSRenesas ElectronicsMonostable Multivibrators
README
README.mdEVA-1_Reproduction
Recreation of the very rare K-K Systems EVA-1 Display Adapter for the Epson HX-20 Computer
In the folder disassembly are three versions of the original firmware:
- eva_orig: original firmware
- eva_enh: enhanced firmware (mostly original)
- eva_ext: extended firmware (8k Text RAM, additional functions)
- see the .asm file for more comments.
The gal folder contains the equations and .jed file for the GAL.
The monitor folder contains a modified version of Daniel Tufvesson's monitor. This is just for testing.
In the rom folder one can find the original rom and the font rom.
The schematics folder contains different versions of the reverse engineering process.
- EVA1: the original reverse engineered schematic and board (NOT FOR PRODUCTION!)
- EVA1_production: the mostly original EVA1 for production (DRAM does NOT work!)
- EVA86-2: from sources on the internet redrawn schematics of the EVA86 (not complete!)
- EVA1_v2: new version with SRAM as Graphic RAM, Arduino as mass storage and RP2040 for VGA Output.
- EVA1_Frontplatte: a drill template for the Strapubox 5003 case
For the newest Hardware Revision (0.5) use the File "disassembly/eva_ext/rom.bin" for a 28C64 or 27C64 ROM.
Parts
160| Qty | Value | Footprint | References |
|---|---|---|---|
| 18 | 100n | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C101, C103, C104, C106, C108, C110, C111, C112, C113, C115, C125, C127, C129, C131, C133, C134 +2 |
| 16 | 100n | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C1, C3, C4, C6, C8, C10, C11, C12, C13, C15, C25, C27, C29, C31, C33, C34 |
| 8 | M3 | MountingHole:MountingHole_3.2mm_M3 | H1, H2, H3, H4, H5, H6, H8, H9 |
| 7 | 10k | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R2, R24, R25, R26, R27, R28, R29 |
| 7 | 74ALS157 | Package_DIP:DIP-16_W7.62mm | U6, U7, U8, U25, U26, U27, U28 |
| 4 | 10u/16 | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C16, C17, C18, C19 |
| 4 | 4k7 | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R5, R113, R117, R121 |
| 4 | 4k7 | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R1, R13, R17, R21 |
| 3 | 2k2 | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R6, R10, R14 |
| 3 | 422E | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R18, R20, R22 |
| 3 | 74HCT74 | Package_DIP:DIP-14_W7.62mm | U4, U23, U24 |
| 3 | 845E | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R16, R19, R23 |
| 3 | SolderJumper_3_Bridged12 | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm | JP1, JP2, JP4 |
| 2 | 1N4148 | Diode_THT:D_A-405_P7.62mm_Horizontal | D1, D2 |
| 2 | 1k | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R12, R15 |
| 2 | 220E | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R7, R11 |
| 2 | 74HCT165 | Package_DIP:DIP-16_W7.62mm_Socket | U10, U35 |
| 2 | 74HCT245 | Package_DIP:DIP-20_W7.62mm | U5, U36 |
| 2 | 74LS573 | Package_DIP:DIP-20_W7.62mm | U2, U14 |
| 2 | 74LVC08 | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U31, U37 |
| 2 | 82E | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R4, R8 |
| 2 | BC337 | Package_TO_SOT_THT:TO-92_Wide | Q2, Q3 |
| 2 | GAL16V8 | Package_DIP:DIP-20_W7.62mm | U32, U45 |
| 1 | 17 | Connector_PinSocket_2.54mm:PinSocket_1x01_P2.54mm_Vertical | J1 |
| 1 | 18M432 | Oscillator:Oscillator_DIP-14 | Y2 |
| 1 | 18M432 | Oscillator:Oscillator_DIP-8 | Y3 |
| 1 | 1n | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C9 |
| 1 | 1n | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C109 |
| 1 | 220E | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R111 |
| 1 | 27C256 | Package_DIP:DIP-28_W15.24mm | U17 |
| 1 | 27C32 | Package_DIP:DIP-24_W15.24mm | U3 |
| 1 | 27C64 | Package_DIP:DIP-28_W15.24mm | U9 |
| 1 | 2k2 | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R106 |
| 1 | 47E | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R9 |
| 1 | 47p | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C7 |
| 1 | 47p | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C107 |
| 1 | 47u/35 | Capacitor_Tantalum_SMD:CP_EIA-7343-31_Kemet-D_Pad2.25x2.55mm_HandSolder | C123 |
| 1 | 47u/35 | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C23 |
| 1 | 4n7 | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C14 |
| 1 | 4n7 | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C114 |
| 1 | 560E | Resistor_THT:R_Axial_DIN0411_L9.9mm_D3.6mm_P12.70mm_Horizontal | R3 |
| 1 | 6803/6303 | Jumper:SolderJumper-2_P1.3mm_Bridged_RoundedPad1.0x1.5mm | JP6 |
| 1 | 74HCT08 | Package_DIP:DIP-14_W7.62mm | U18 |
| 1 | 74HCT14 | Package_DIP:DIP-14_W7.62mm | U22 |
| 1 | 74HCT32 | Package_DIP:DIP-14_W7.62mm | U12 |
| 1 | 74HCT86 | Package_DIP:DIP-14_W7.62mm | U19 |
| 1 | 74LS107 | Package_DIP:DIP-14_W7.62mm | U29 |
| 1 | 74LS221 | Package_DIP:DIP-16_W7.62mm | U13 |
| 1 | 74LS290 | Package_DIP:DIP-14_W7.62mm | U20 |
| 1 | 8 | Connector_PinSocket_2.54mm:PinSocket_1x01_P2.54mm_Vertical | J7 |
| 1 | 9 | Connector_PinSocket_2.54mm:PinSocket_1x01_P2.54mm_Vertical | J6 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U33 |
| 1 | AUTO_ADJUST | Button_Switch_THT:SW_Tactile_SPST_Angled_PTS645Vx83-2LFS | SW2 |
| 1 | BAS | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J2 |
| 1 | BAT54AW | Package_TO_SOT_SMD:SOT-23_Handsoldering | D3 |
| 1 | Barrel_Jack_Switch | Connector_BarrelJack:BarrelJack_Wuerth_6941xx301002 | J8 |
| 1 | CSYNC/HS | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm | JP5 |
| 1 | CY62256-70PC | Package_DIP:DIP-28_W15.24mm | U11 |
| 1 | Conn_01x02 | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J13 |
| 1 | Conn_01x06 | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J12 |
| 1 | Conn_Coaxial | my_own_conn:Keystone_RCA-Jack | J11 |
| 1 | Converter | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J9 |
| 1 | DE15_Plug_HighDensity_MountingHoles | Connector_Dsub:DSUB-15-HD_Female_Horizontal_P2.29x1.90mm_EdgePinOffset3.03mm_Housed_MountingHolesOffset4.94mm | J3 |
| 1 | Graphics kicad | Symbol:KiCad-Logo2_6mm_SilkScreen | H7 |
| 1 | HX20 | my_own_conn:DIN-5_Stereo | J4 |
| 1 | HY6264AxP | Package_DIP:DIP-28_W15.24mm | U1 |
| 1 | MAX232 | Package_DIP:DIP-16_W7.62mm_Socket | U30 |
| 1 | MC6803 | Package_DIP:DIP-40_W15.24mm_Socket | U15 |
| 1 | MC6845 | Package_DIP:DIP-40_W15.24mm_Socket | U16 |
| 1 | Micro_SD_Card_Det2 | Connector_Card:microSD_HC_Hirose_DM3D-SF | J10 |
| 1 | PX_CLK_BTN | Button_Switch_THT:SW_Tactile_SPST_Angled_PTS645Vx83-2LFS | SW1 |
| 1 | RaspberryPi_Pico | MCEBlaster:raspberry_pi_pico | U34 |
| 1 | SCLK*2 | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | JP9 |
| 1 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP10 |
| 1 | Sparkfun_Pro_Micro | Arduino:Sparkfun_Pro_Micro | U21 |
| 1 | Straight Cable | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | JP8 |
| 1 | SyncPolarity | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm | JP3 |
| 1 | TA11_on_off | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm | JP7 |
| 1 | TF20 | my_own_conn:DIN-5_Stereo | J5 |
| 1 | TestPoint | TestPoint:TestPoint_Loop_D1.80mm_Drill1.0mm_Beaded | TP1 |
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Questions
How big is the EVA1 v2 PCB?
It measures 218 × 125 mm and has 2 copper layers, 1.6 mm thick.
What parts does the EVA1 v2 use?
160 parts, built around the 74HCT245, MAX232N, 27C256-17/J and 74HCT74D. 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 EVA1 v2 KiCad files?
From the roberto314/EVA-1_Reproduction repository on GitHub, at the commit this page was made from: the board is schematics/EVA1_v2/EVA1_v2.kicad_pcb and its schematic schematics/EVA1/EVA1.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the EVA1 v2 design in my own project?
Its repository states no licence, so its author keeps all rights: ask roberto314 before reusing the design.