Open source cartridge

Por abiliojr

Supporter (8)

Imagen del abiliojr

31-07-2018, 22:05

A few months ago I received an MSX computer from a good friend of mine. I never owned an 8-bit computer before (my first computer was an XT). After a lot of awe for the simpler MSX days, I decided to look how to start a project around it. My plan is to build yet-another cartridge for the MSX, taking some ideas from current ones. Here my own wishlist:

  • Open source hardware
  • Inexpensive
  • Easy to assemble at home using only a soldering iron,
  • FPGA to implement all that extra hardware, like memory pagers and sound chips.
  • Big enough RAM and Flash.
  • WiFi access (to load applications into the machine).
  • DAC to generate audio (in the future).
  • Loadable over USB.
  • SD card (maybe, depends on I/O lines).
  • Logic Analyzer option (to debug the cartridge in it's initial state, over USB).

In order to implement it, I plan to use:

  • Intel MAX10 or CYC10, already soldered in one of these boards (MAX1000, CYC1000). The first one comes in 8k and 16k logic elements, and the last one in 25k. Price range: €22-34, also sold by Arrow. They provide 8 Mb of RAM, and 8 Mb (2Mb in the cyclone) of flash, and come with headers people can solder home. They are exchangeable.
  • 74LVC245: to do 3.3V / 5V level conversion, and also to multiplex some signals and reduce pin count. Around 50 cents in sites like digikey.
  • ESP32 wroom (or an ESP-8266): I know, is powerful enough to emulate the whole computer, but I will only use it for network access. Out of the box it comes flashed with an "AT" firmware that implements TCP/UDP and TLS. Is easy to extend it with HTTP/FTP and Telnet on the same board. It's retail price is around €6. If WiFi is not desired, it can be skipped.
  • A double sided PCB you can manufacture by $5 for 10 units (plus shipping) in China.

So far this is just an idea that covers my personal needs, but I would love to hear suggestions on how to improve it, as I wish to make it an open source project.

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Por hardwaremaker

Master (223)

Imagen del hardwaremaker

01-08-2018, 00:28

Sounds good. The FPGA boards are very small, and can fit into a cartridge case.

Por abiliojr

Supporter (8)

Imagen del abiliojr

01-08-2018, 11:15

Any good source for those cartridges without cannibalizing old ones? It would be good to know the dimensions in advance (is of my of understanding that there are subtle differences even for the official ones)

Por Grauw

Ascended (8457)

Imagen del Grauw

01-08-2018, 11:53

You can buy nice cases from Korean MSX user Overrich, large quantities tho. I think you can get individual pieces from ericb's webshop.

Por FiXato

Scribe (1520)

Imagen del FiXato

01-08-2018, 17:36

Por hardwaremaker

Master (223)

Imagen del hardwaremaker

01-08-2018, 18:10

What software do you use for design the board? I have an Eagle library with the dimensions of the board, compatible with Overrich's cartridge cases.

Por abiliojr

Supporter (8)

Imagen del abiliojr

01-08-2018, 22:51

So far the plan is to use kicad. Can you convert the files to gerber?

Por Alexandre_Taito

Champion (325)

Imagen del Alexandre_Taito

02-08-2018, 12:08

You can get cartridge shells from Paulo Maluf in Brazil (I can send his contact in private)

Por lintweaker

Master (156)

Imagen del lintweaker

03-08-2018, 09:15

Nice plan! I really like to get into FPGA's as well but the still not managed to it...

Ordering Overrich's cartridges seems difficult due to the Korean site. They look nice.

Por hardwaremaker

Master (223)

Imagen del hardwaremaker

04-08-2018, 20:22

abiliojr wrote:

So far the plan is to use kicad. Can you convert the files to gerber?

Yes, I can make gerber files. Please e-mail me for send you the files.