Xt isa umb
About the Xt isa umb PCB
Xt isa umb is an open source PCB design by zyga64, published on GitHub. It is a 2-layer board measuring 94 × 60.5 mm, with 14 components from 9 distinct parts.
Other key parts include the 74LS138, 74LS08, AS6C1008 and 74HCT245. By type, the board carries 5 capacitors, 4 ICs, 2 jumpers, 2 resistors and 1 connector.
From the project
UMB memory expansion (128kB) for IBM PC (XT) and clones
With this card, you can add 128 kB of continuous UMB memory in the D0000 - EFFFF area, or only 64 kB in the D0000 - DFFFF or E0000 - EFFFF areas.
Original schematic diagram was drawn by Ruud Baltissen (VCF forum thread): https://forum.vcfed.org/index.php?threads/loading-dos-high-on-a-xt.32320/ The idea for the printed circuit board layout borrowed from Adrian Black: https://github.com/misterblack1/isa-ram-expansion 8 bit ISA footprint from Sergey Kiselev: https://github.com/skiselev/mykicad_library
Main components on the Xt isa umb
Xt isa umb bill of materials (BOM)
14 components, 9 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | 74LS138 | DIP-16_W7.62mm | U1 |
| 1 | 74LS08 | DIP-14_W7.62mm | U2 |
| 1 | AS6C1008 | DIP-32_W15.24mm | U3 |
| 1 | 74HCT245 | DIP-20_W7.62mm | U4 |
| 1 | Bus_ISA_8bit | Conn_Edge_PCB_ISA8 | J1 |
| 2 | Jumper_2_Bridged | PinHeader_1x02_P2.54mm_Vertical | JP1, JP2 |
| 4 | 100nF | C_Disc_D4.7mm_W2.5mm_P5.00mm | C1, C2, C3, C4 |
| 1 | 47uF | CP_Radial_D4.0mm_P2.00mm | C6 |
| 2 | 15k | R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1, R2 |
Xt isa umb design files
The KiCad project lives in the zyga64/xt-isa-umb repository on GitHub; these links point at the commit this page was built from.
- Layoutxt-isa-umb.kicad_pcb
- Schematicxt-isa-umb.kicad_sch
Xt isa umb: common questions
How big is the Xt isa umb PCB?
The Xt isa umb measures 94 × 60.5 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Xt isa umb?
14 components, from 9 distinct parts. The full bill of materials is listed on this page.
Where can I download the Xt isa umb design files?
From the zyga64/xt-isa-umb repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.
Can I use the Xt isa umb design in my own project?
The repository has no license, so all rights stay with zyga64. Use it as a reference, and ask the author before reusing the design.