2 layers97.8 × 35.6 mm
QL external ram 892Kb
alvaroalea/QL_RAM_Expansions
Severa RAM expansion boards for the Sinclair QL
14 parts8
2 layers97.8 × 35.6 mm
Qlexternal512kram MIX
alvaroalea/QL_RAM_Expansions8Severa RAM expansion boards for the Sinclair QL
- Size
- 97.8 × 35.6 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 15
- Nets
- 72
- Pads
- 209
- Tracks, vias
- 931, 16
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 13 Feb 2022
- Updated
- 23 Mar 2026
Overview
Qlexternal512kram MIX is an open-source printed circuit board by alvaroalea, from the alvaroalea/QL_RAM_Expansions repository on GitHub. It is a 2-layer board of 97.8 × 35.6 mm with 15 parts on 72 nets, routed with 931 tracks and 16 vias.
It is built around the LM1117-5.0. Its parts include 4 capacitors, 3 resistors, 3 ICs and 2 connectors. It belongs with the FPGA and CPLD boards of this library.
Main components
1README
QL_external_ram_896Kb/README.mdSINCLAIR QL 896kB External Rom Expansion
(C) 2026 Alvaro Alea Fernandez
License under: CERN Open Hardware Licence Version 2 - Strongly Reciprocal
https://ohwr.org/cern_ohl_s_v2.txt
This is based on the work of McLeod Ideafix, Jose Leandro, Zerover and tcat between others.
This board will provide up to 768kB aditional of static RAM (fast-ram) to the sinclair QL.
This board can be stacked with my old external ram board, jumpers allow a 512Kb, or +256Kb configs of the old board.
There is also a expecial 832Kb config that free the 64Kb top memory for aditional boards without use the ROM Cartridge area (Jose Leandro's QuBide...)
Provide a expansion conector to allow conect aditional interfaces.
There area available 4 configuration trough a dip switch in the PCB.
- 640kB - This is the standar 512kB expansion for any QL
- 832kB - Similar to 256kB provide aditional space for expansion cards correctly configured.
- 896kB - Maximin RAM do not provide aditional space for expansion cards.
- Expecial - This is for use as a second expansion, use the full QL space for a maximun of 898kB, be aware that this is incompatible with a lot of expansion card, so use with caution (Any expansion card that do not use jumper for configuration will be incompatible).
In the GAL folder there is the source code to be compiled with GALasm that you can found here: https://github.com/daveho/GALasm
Mini Trump Card Compatibility
I have done a version of the trump card disk interface here: https://github.com/alvaroalea/QL_MiniTrump3 , this interface do not provide memory like the original one. You can combine both cards to mimic the original trump card.
You shall connect this board after the minitrump, you need to change the solder jumper (JP1) to 1-2 to allow the Minitrump card to coordinate with the second memory card.
This jumper can be alwais 1-2, 2-3 is only used if you have another card that need BERR signal (none as far as I know).
Parts
15| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 10K | Resistor_SMD:R_1206_3216Metric_Pad1.30x1.75mm_HandSolder | R1, R2, R3 |
| 2 | 100n | Capacitor_SMD:C_1206_3216Metric_Pad1.33x1.80mm_HandSolder | C3, C4 |
| 2 | Jumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP1, JP2 |
| 1 | 100u/16V | Capacitor_SMD:CP_Elec_6.3x5.4 | C2 |
| 1 | 100u/25V | Capacitor_SMD:CP_Elec_6.3x5.4 | C1 |
| 1 | GAL16V8B-25QP | Package_DIP:DIP-20_W7.62mm_LongPads | U2 |
| 1 | HM628512BLFP-7 | Package_SO:SSOP-32_11.305x20.495mm_P1.27mm | U1 |
| 1 | Jumper_3_Open | Jumper:SolderJumper-3_P1.3mm_Open_Pad1.0x1.5mm | JP3 |
| 1 | LM1117-5.0 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U3 |
| 1 | QL_SLOT_DIN41612_FEMALE-90degrees | 8bits:DIN41612_B_2x32_Female_Horizontal_THT | J1 |
| 1 | QL_SLOT_DIN41612_MALE_90degrees | 8bits:DIN41612_B_2x32_Male_Horizontal_THT | J2 |
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Questions
How big is the Qlexternal512kram MIX PCB?
It measures 97.8 × 35.6 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Qlexternal512kram MIX use?
15 parts, built around the LM1117-5.0. 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 Qlexternal512kram MIX KiCad files?
From the alvaroalea/QL_RAM_Expansions repository on GitHub, at the commit this page was made from: the board is qlexternal512kram_MIX/qlexternal512kram_MIX.kicad_pcb and its schematic QL_external_ram_896Kb/QL_external_ram_892Kb.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Qlexternal512kram MIX design in my own project?
Its repository states no licence, so its author keeps all rights: ask alvaroalea before reusing the design.