EPROM Card
About the EPROM Card PCB
EPROM Card is an open source PCB design by codesqueak, published on GitHub under the CERN-OHL-S-2.0 license. It is a 2-layer board measuring 203.2 × 203.2 mm, with 77 components from 28 distinct parts.
Other key parts include the 74LS244, DecodeHeader, 74159, 74LS175 and 74LS32. By type, the board carries 18 ICs, 18 resistors, 5 diodes, 4 test points, 2 switches and 1 transistor.
It belongs with the retro computing designs in this gallery.
From the project
An EPROM card for Nascom / Gemini / 80-Bus Z80 Systems - 2716 / 2732 Devices
This card has been designed to replace the use of 2708/2716 EPROM’s with the more readily available and simpler to program 2732 / 2764 devices.
The board support up 5 devices or 4 devices and the original 8K Basic ROM. Both a 2732/2764 EPROM and the Basic ROM may be present on the card simultaneously, with the active device being selected via a switch
Each device may be decoded to any 4K boundary, with a typical configuration being:
Main components on the EPROM Card
EPROM Card bill of materials (BOM)
77 components, 28 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | 74LS244 | DIP-20_W7.62mm_Socket | U1, U3, U5 |
| 1 | DecodeHeader | DIP-24_W15.24mm | U2 |
| 1 | 74159 | DIP-24_W15.24mm_Socket | U4 |
| 1 | 74LS175 | DIP-16_W7.62mm_Socket | U6 |
| 1 | 74LS32 | DIP-14_W7.62mm_Socket | U7 |
| 1 | 7406 | DIP-14_W7.62mm_Socket | U8 |
| 1 | 74LS20 | DIP-14_W7.62mm_Socket | U9 |
| 1 | 74LS04 | DIP-14_W7.62mm_Socket | U10 |
| 1 | 74LS00 | DIP-14_W7.62mm_Socket | U11 |
| 1 | 74LS30 | DIP-14_W7.62mm_Socket | U12 |
| 5 | 2764 | DIP-28_W15.24mm | U100, U101, U102, U103, U201 |
| 1 | MK36000_8K_ROM | DIP-24_W15.24mm | U200 |
| 1 | 2N3904 | TO-92_Inline_Wide | Q1 |
| 1 | Conn_01x80NasBus | 80BusEdgeConnector | J1 |
| 17 | 10nF | C_Disc_D3.4mm_W2.1mm_P2.50mm | DC1, DC2, DC3, DC4, DC5, DC7, DC8, DC9 +9 |
| 1 | Link 1 | SW_DIP_SPSTx01_Slide_6.7x4.1mm_W7.62mm_P2.54mm_LowProfile | JP1 |
| 1 | SW_DIP_x06 | DIP-12_W7.62mm_Socket | SW1 |
| 1 | SW_SPDT | PinHeader_1x03_P2.54mm_Vertical | SW2 |
| 1 | Data ~OE~ | TestPoint_THTPad_D1.5mm_Drill0.7mm | TP1 |
| 1 | ~RAMDIS~ | TestPoint_THTPad_D1.5mm_Drill0.7mm | TP2 |
Show 8 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | Bank Select | TestPoint_THTPad_D1.5mm_Drill0.7mm | TP3 |
| 1 | 0V / Ground | TestPoint_THTPad_D1.5mm_Drill0.7mm | TP4 |
| 10 | 10uF | C_Disc_D5.0mm_W2.5mm_P5.00mm | Tant1, Tant2, Tant3, Tant4, Tant5, Tant6, Tant7, Tant8 +2 |
| 5 | LED | LED_D3.0mm | D1, D2, D3, D4, D5 |
| 3 | 330 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R1, R4, R15 |
| 3 | 1k | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R2, R3, R12 |
| 10 | 2K2 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R5, R6, R7, R8, R9, R10, R11, R14 +2 |
| 2 | 4K7 | R_Axial_DIN0309_L9.0mm_D3.2mm_P12.70mm_Horizontal | R13, R18 |
EPROM Card design files
The KiCad project lives in the codesqueak/EPROM_Card repository on GitHub; these links point at the commit this page was built from.
- Layoutkicad/80bus.kicad_pcb
- Schematickicad/80bus.kicad_sch
EPROM Card: common questions
How big is the EPROM Card PCB?
The EPROM Card measures 203.2 × 203.2 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the EPROM Card?
77 components, from 28 distinct parts. The full bill of materials is listed on this page.
Where can I download the EPROM Card design files?
From the codesqueak/EPROM_Card repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the EPROM Card design in my own project?
Yes, under the terms of its CERN-OHL-S-2.0 license, which codesqueak chose for the repository.
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