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Communication port information
BrokenLizard - Nov 22, 2009

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  zone66x Mar 19, 2016
Excellent excellent. The exact info I needed to test the 5v line with my custom connector. Best news is it actually works

I'm trying make my DaVinci 2.0 Duo print like it had a 0.18mm nozzle when in reality it has a 0.4mm one which is pretty standard for printers. I'm going to continue to try to tweak my design so it can be printed on cheap printers,


Hopefully this will make the communication port more accessible for people who want to use it for modding.



  BrokenLizard Mar 22, 2016
The 5V line is a signal line and should not be used as a power source. In my design, I'm using that signal to indicate when the Saturn system is on or has been power cycled. The communication protocol for the FDD isn't very robust, so detecting a system reset is unfortunately rather important.

zone66x, would you be willing to send me a copy of your connector design files? I've been planning on creating a connector with a 3D printer, but the past year has been very hectic with work. The connector, combined with a couple of hardware improvements that I've been able to make over the past year, may finally make refining my design into a sell-able device feasible.

miyasan, You are correct about the 28 bytes in the change partition command, but that is indicated in the protocol document. That portion of the transfer is sent as a full block and thus follows the full block protocol (which includes a 4 bytes header and a 4 byte CRC).

 zone66x Mar 22, 2016
Hey BrokenLizard,

Glad to see your still alive and kicking


  
	
	

		
		

			The 5V line is a signal line and should not be used as a power source. In my design, I'm using that signal to indicate when the Saturn system is on or has been power cycled. The communication protocol for the FDD isn't very robust, so detecting a system reset is unfortunately rather important.


Yeah read your PDF document describing as much. It's not the end of the world if one must rely on an external power source. I was planning to do some test with an ArduinoNano which can get it's power from the USB or an adapter. The SH-2 is wonderfully flexible in how it can communicate via serial so I if a cheap device like an ArduinoNano is used it will open many possibilities via it's many modules like sd card slot, wifi and bluetooth.


  
	
	

		
		

			zone66x, would you be willing to send me a copy of your connector design files? I've been planning on creating a connector with a 3D printer, but the past year has been very hectic with work. The connector, combined with a couple of hardware improvements that I've been able to make over the past year, may finally make refining my design into a sell-able device feasible.


I started working on creating a communication port connector because your work and dilemma in producing a connector inspired me. I'm planning to put the connector design on my thingiverse... account at some point so anyone can make the connector and hopefully make devices to work with it. I tend to only put up designs that I've actually be able to successfully print consistently I still need to sort things out before I upload though.

I use a "cheap" DaVinci 2.0 Duo which uses the more widespread, accessible and cheaper FDM technology. What printer do you have or are planning to use? If your planning to use an SLA printer then the tolerances of my design will need to be adjusted due to the increased precision of those printers.

Here's some pictures of some of the design... andtest print process... for anyone who's interested in 3d printing

My current design is using Molex spring type connector used... for connectors like the one used to power floppy drives. It seems to work but they are wider and thicker than what is actually needed. The main problem with this is that the walls between the pins and outer walls of the connector are very thin (~0.2mm and ~0.4mm respectively). If anyone knows of readily available alternative let me know I still think that a design using male DuPont... pins should be possible, but I'm a bit worried that the it's inflexibility of the DuPont pins may possibly wear out the Saturn's communication port pin prematurely.

The male DuPont pins would be great to make a printable controller port connector though! Another project in the near future maybe ....

Anyhow it's almost time for bed and I still want to get some SH-2 assembly working on my Saturn so I guess I'll leave it at that. Again, Glad to see you're still around and working on your backup thing for the Saturn

Regards,


Alex

 BrokenLizard Mar 23, 2016
I guess putting my personal projects on hold for a while really shows. I can't even remember what I included in my own document! Anyway, I'm planning on getting back into the mix once I can finally finish rebuilding my server.

As for the connector pins, I actually found a couple potential contacts back when work first got their 3D printer. I'll go back through my notes and try to find the part numbers. Mounting these contacts might be more challenging than the contacts you mentioned, but at least from the pictures and datasheets that I've found, appear to have a greater resemblance to the original contacts.

 BrokenLizard Mar 23, 2016
I just discovered that I never uploaded the latest version of my FDD protocol document to my server, so for the past 5 years it has been slightly out of date. I'll need at least a couple of days to review it, but then I'll upload the latest version.

 zone66x Mar 23, 2016

BrokenLizard said:


*Imagines some mad scientist lab with wires, electronics and papers everywhere*

Amazing that it's been over 20 years since the Sega Saturn was born. Look like some of us still haven't forgotten it and are still trying to make that next awesome mod.

 zone66x Mar 23, 2016

BrokenLizard said:


I WANT IT NOW!

jk jk

After 5 years, I think 2 days of review won't disappoint anyone. There's so little documentation regarding the communication port that even your outdated pdf is still very much appreciated.

 BrokenLizard Mar 24, 2016
My work has a MakerBot Replicator 5th Gen with the specifications listed below. There are a few local companies that rent out time on higher quality printers as well. Given that the only quote I could get for professionally made molded connectors was $9,000 (for the first batch of 100 12" single ended cables), rental costs should be far more reasonable.

Print Technology: Fused deposition modeling
Build Volume: 25.2 L x 19.9 W x 15.0 H cm [9.9 L x 7.8 W x 5.9 H in]
Layer Resolution: 100 microns
Filament: 1.75 mm [0.069 in] MakerBot PLA Filament
Nozzle Diameter: 0.4 mm [0.015 in]

As for the contacts, I still have not found my notes with part numbers yet, but I was originally envisioning using contacts of the type general type found in SIM card readers (see the linked picture). I know there are companies that sell the contacts individually, but it will take a little bit of searching. I also have access to friends who are fluent in Chinese so that might help in the search.

  miyasan Mar 29, 2016
I got ss-fdd. it is very expensive...

I monitored SPI between Saturn and FDD.
I wrote a little about it.

<>
(1) send command token(4byte + CRC4byte)
{0x80, 0x11, (uint16)partition number, CRC}

(2) get ACK(4byte + CRC 4byte)
{0x20, 0x00, 0x00 0x00, CRC...}

(3) get device information(24byte + CRC 4byte)
[0]0x10: start token
[1]0xff:
[2]-[3]0x0014: total of data
[4]0x00: device ID.
[5]0x02: total of partition.
[6]0x05: SPI clock.
[7]0x0c: unknown
[8]-[11]0x000b4000: total bytes.
2HD fdd capacity are 1474560bytes, so half are 737280bytes = 0x0b4000.
[12]-[15]0x000000b4: total clusters.
1cluster is 4096bytes = 0x1000
[16],[17]0x1000: unknown, maybe read max?
[18],[19]0x1000: unknown , maybe write max?
[20]-[23]0x00005000: unknown
[24]-[27]0x0000fae2: CRC

(4) get Floppy state(4byte + CRC 4byte)
{0x20, 0x00, 0xff, 0x00, CRC 4byte}

 zone66x Mar 29, 2016
Hey all,

I just posted the 3d files to print the male communication port connector I made. It's still a work in progress but it's usable in it's current state. Better having something than nothing at all.

3D printer files

Enjoys,

Alex

 BrokenLizard Mar 30, 2016
I just updated my Sega Saturn Floppy Disk Drive Communication Protocol document to version 1.4.

Alex, thanks for the 3D models! I'm still looking into finding smaller, gold plated contacts but so far everything I've found would require disassembling an existing connector.

Currently, I'm in the process of updating my design to use a faster microcontroller and potentially connect to the SD card using SQI. Additionally, I'm exploring a new protection circuit design for protecting the Sega Saturn's communication port incase contention occurs. This new design might enable faster data transfers, but I will need to test its response dynamics first.

Especially since my work bought a 3D digitizer, this recent progress may enable the selling of realistic looking SD card-based floppy drive replicas within a few months.

 BrokenLizard Mar 30, 2016
Here is a data sheet with potential contacts. While this week is rather hectic for me, I'll try and go over the dimensions within a few days and see if any of these might work.

 zone66x Mar 30, 2016
1447360-9, 1447360-8, 1871059-1 look like the most likely candidates. These all meant to be surface mounted to a PCB though. To use them properly you would need two separate very thin PCBs and solder the pins to them. I guess it's not the end of the world but it would complicate things a bit. Another option would be to maybe use wire and conductive epoxy.

 BrokenLizard Mar 30, 2016
We could use PCBs, but I was sort of hoping we could solder wire to the contacts and then pot them. This might require a multi-part connector though.

 zone66x Mar 30, 2016

BrokenLizard said:


Yeah true could try that. I was actually looking for the contacts on aliexpress but didn't have any luck finding them. Found them on digikey though.

 BrokenLizard Apr 11, 2016
Just wanted to let everyone know I'm still aound and I'm planning on working on the connector soon. I've had very little free time lately and I've been using the time that I do have to finish up a translation project. It's too difficult to simultaneously work on multiple projects, so I'm trying to complete the short ones first.

 ScubaSteve Mar 16, 2019
Excuse me while I resurrect this thread. I can't get the documents about the port communication, and this thread died out .wassup.

 vbt Mar 17, 2019
I've attached the BrokenLizard...'s file my answer
pseudo saturn kai by cafe-alpha... supports the floppy disk, you can have a look at the source code here : PPCenter :: Pseudo Saturn Kai...
FDD Operator is here : http://segaxtreme.net/content/satdev/Tools/sega/FD...
BrokenLizard's newest page : Sanford T. Freedman | Projects | FloppyFake... (thanks SteveKwok)

 ScubaSteve Apr 2, 2019

vbt said:

Awesome, thank you. I'm Godkingofcanada btw, from the yaba freenode. I 3d printed 6 of the comm port adapters and just wired one.

 ScubaSteve Apr 2, 2019
For the comm port, comm 9 through 11 aren't listed on the schematics that I can see, what are they?

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