4 layers101.6 × 53.3 mm
2 layers26.9 × 35.1 mm
C64-sram
jamarju/c64-sram62SRAM substitute for C64C shortboards
- Size
- 26.9 × 35.1 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 5
- Nets
- 48
- Pads
- 102
- Tracks, vias
- 355, 31
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 4
- Created
- 24 Mar 2018
- Updated
- 26 Mar 2018
Overview
C64-sram is an open-source printed circuit board by jamarju, from the jamarju/c64-sram repository on GitHub. It is a 2-layer board of 26.9 × 35.1 mm with 5 parts on 48 nets, routed with 355 tracks and 31 vias.
It is built around the 74HCT573D.
Main components
1README
README.mdCommodore 64 (C64C) SRAM replacement
This is a static RAM replacement for C64C chips U10 and U11 (motherboards assy no. 250469).
It may also work on assy no. 250466 (DRAM chips U9 and U10), but I have only tested it on a 250469 board.
It is based on Gerrit4's design, originally posted at the lemon64 forum.
Building
See bom and gerber if you wish to build your own.
You can use any pin headers you find suitable but I suggest 0.50 mm round pin headers so as not to put too much stress on the sockets. They are easy to find on Aliexpress as "gold round male pin".
You can solder all 36 pins of U10 and U11 as in the pictures below, however only these 23 pins are strictly needed:
- U10: pins 2, 3, 15, 17, 18
- U11: all pins required
For soldering convenience and better board support I suggest soldering the following:
- U10: solder pins 2, 3, 15, 16, 17, 18
- U11: solder all pins
Thanks
Gerrit4 for the schematic design.
Parts
5| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | TMS4464 | Housings_DIP:DIP-18_W7.62mm_LongPads | U10, U11 |
| 1 | 74F32 | footprints:SOIC-14_6x8.65 | IC3 |
| 1 | 74HCT573 | footprints:TSSOP20_4.4x6.3_p0.65 | IC2 |
| 1 | IS61C1024AL | footprints:TSOP_I_32L_8x20_p0.5 | IC1 |
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Questions
How big is the C64-sram PCB?
It measures 26.9 × 35.1 mm and has 2 copper layers, 1.6 mm thick.
What parts does the C64-sram use?
5 parts, built around the 74HCT573D. 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 C64-sram KiCad files?
From the jamarju/c64-sram repository on GitHub, at the commit this page was made from: the board is kicad-project/c64-sram.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the C64-sram design in my own project?
Its repository states no licence, so its author keeps all rights: ask jamarju before reusing the design.