Questions & Answers - synthtools/opensrxcard GitHub Wiki

Disclaimer

I’m a electronics hobbyist. Everything is self-taught. I have created this primarily for my own use and provide the material as is. Use at your own risk. If you burn your house or damage your devices, I cannot be held responsible no matter whether it is your fault when assembling or my fault due to the design. I can only provide very limited assistance through github. You have been warned. If in doubt, please go to someone or buy from someone who knows what he is doing, is insured for damages he causes and possibly provides warranty on the cards. Make sure you read and understand the license.

I’m a user, where can I buy these cards?

I don’t offer and sell these cards. I only provide the material necessary to produce these cards. Please don’t ask me for sellers, I also won’t list sellers on this github page as I likely won’t know these sellers and can not guarantee that these cards will work and are produced correctly. If you like, you can share your experiences with sellers in a discussions thread. Make sure that your seller provides a reasonable refund policy, doesn’t ask for unreasonable prices per card and provides help and support for the usage. I will only provide limited help through these pages.

I’m a seller, can I sell these cards?

Yes, you are welcome to do so. I would welcome fair prices for the community. For example, more than $70 per card is too much in my opinion even when the through-hole parts are already hand-assembled. Consider offering kits so that the users can solder the through-hole parts. However, you must make sure to honor the license. I have chosen a rather strict open hardware license which requires you to make all changes available under this license again, even if you only provide altered binaries, firmware bitstreams or similar. You essentially cannot legally change the design or source code without making it open source under the same license again. My goal is to keep this card and the source code for the software that comes along with it in all its variations open-source for the community. You should not profit from changes and improvements based on this design that you keep for yourself and the things you sell. You must keep a pointer to the creator and to this github page. Make sure you read and understand the license.

What is the difference between the 3.3v and the 5v card?

Roland devices that support SRX cards can work with either 5V (for example Roland XV-5080 or Roland XV-3080) or 3.3V (Roland Fantom X, Fantom XR). The modern flash nors used on the opensrxcard support only 3.3v. As a result, when an opensrxcard should be used in a Roland 5V device, the pins need to be level shifted from 5v to 3.3v and vice versa.

Currently, only the 3.3V card without level shifting and voltage regulation is ready. The 5V version will work on both 3.3V and 5V devices. However, due to the additional components that it needs, it likely will require SMD components hand assembled on the back side. Thus, I will keep the 3.3V version as it is easier and cheaper to assemble for users of 3.3V devices.

What are the unassembled parts on the opensrxcard?

There is a second 256 byte microwire eeprom on the srx card. I have dumped two eeproms of this kind from two original SRX cards and it was empty for both. As a result, I have tried the opensrxcard without this second eeprom and everything worked just fine. I have no knowledge why this eeprom exists, but it seems that it isn’t actively used, at least for the devices that I have tested. If you have any further knowledge on this, feel free to post this information in the github discussions.

How can I create my own custom cards?

This aspect of the project has not been started yet. So it’s not yet possible. However, when you dump cards and are technically able to do so, you might want to help to reverse-engineer the SRX image format and build tooling for it. To my knowledge, not much about it is currently known. However, it is known how to scramble/descramble the image and how the DPCM encoding/decoding works.

Does this work on a Mac as well?

Yes, maybe. I don't have a Mac any more, so I cannot test the srxtool for Macs, neither Intel nor Apple Silicon. As a result, I don't provide cross-compiled binaries as I don't want to provide builds that I haven't seen working. The compilation process for the srxtool is very easy. Give it a try and report back.

The firmware programming requires a system where Arduino IDE 2 is supported.