2 layers50 × 99 mm
2 layers50 × 99 mm
EXLROM 4Mbit
BrettHallen/Exelvision2Exelvision hardware projects
- Size
- 50 × 99 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 9
- Nets
- 33
- Pads
- 78
- Tracks, vias
- 191, 19
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 31 Mar 2025
- Updated
- 24 Apr 2025
Overview
EXLROM 4Mbit is an open-source printed circuit board by BrettHallen, from the BrettHallen/Exelvision repository on GitHub. It is a 2-layer board of 50 × 99 mm with 9 parts on 33 nets, routed with 191 tracks and 19 vias.
Its parts include 4 resistors, 1 capacitor, 1 IC, 1 connector and 1 switch.
README
README.mdExelvision EXL100
Hardware projects and other info for the French Exelvision EXL100 computer.
It has the following main ICs:
- Texas Instruments TMS4408 ... 8k x 4bit giving 32KBytes of shared VRAM
- NEC D4016 ... 2KByte SRAM for CPU RAM
- Texas Instruments TAL004 ... Gate Array
- Texas Instruments L30002N ... TMS 7220 CPU
- Texas Instruments C34802N ... TMS 7041 peripheral co-processor
- Texas Instruments TMP5220CNL ... TMS 5220 speech synthesiser
- Texas Instruments TMX3556NS ... TMS 3556 video display processor (VDP)
The ROM cartridge connector is a BURNDY PWBH14DER1A-1 which I can't find any info on - it's a 2x14 design.
YouTube Videos
- Part 1: First Look
- Part 2: Cartridge Pinout
- Simple Kicad For Simple Vintage Computer Hobbyists: Part 4 (ROM Cartridge Design)
- Part 3: DIY Cartridges
EXLROM - Multi-ROM cartridge
The EXL100 could accept ROM cartridges from 8KByte to 32KByte in size, including BASIC. By using a 4Mbit ROM (27C040) we can fit all known ROMs onto one cartridge. How exciting.
I've designed two versions: a simple 256kbit version that will hold a single 32KByte ROM (like the olden days) and the 4Mbit version that will hold up to 16 32KByte ROMs.
Status
- 1-Apr-2025: Pending test fabrication
- 10-Apr-2025: Test PCBs arrived & verified! Refer YouTube video.
Partial TAL004 Gate Array Pinout
From cartridge pinout investigation ...
Parts
9| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 10KΩ | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2, R3, R4 |
| 1 | 100nF | Capacitor_THT:C_Disc_D3.0mm_W2.0mm_P2.50mm | C1 |
| 1 | 27C040 | Package_DIP:DIP-32_W15.24mm_Socket | U1 |
| 1 | EXL100 Cartridge | Clueless_Engineer:EXL100_Cartridge | J1 |
| 1 | LOGO | LOGO | G*** |
| 1 | SW_DIP_x04 | Button_Switch_THT:SW_DIP_SPSTx04_Slide_9.78x12.34mm_W7.62mm_P2.54mm | SW1 |
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Questions
How big is the EXLROM 4Mbit PCB?
It measures 50 × 99 mm and has 2 copper layers, 1.6 mm thick.
What parts does the EXLROM 4Mbit use?
9 parts. 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 EXLROM 4Mbit KiCad files?
From the BrettHallen/Exelvision repository on GitHub, at the commit this page was made from: the board is EXLROM/EXLROM_4Mbit/EXLROM_4Mbit.kicad_pcb and its schematic EXLROM/EXLROM_256Kbit/EXLROM_256kbit.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the EXLROM 4Mbit design in my own project?
Its repository states no licence, so its author keeps all rights: ask BrettHallen before reusing the design.