The Retrosys is born

Sachiel7

Hey everyone,
I'd just like to post some info on my latest project utilizing the power of the Propeller chip, the Retrosys.
Its a game console, much like the Hydra (to whom I gladly tip my hat), here are some of it's features:

-Two SEGA Genesis controller ports·w/ six button support, ability to interface to other
·peripherals
-TV Out (No VGA, I wanted to treat it as more of a standard console)
-Stereo sound output ( )
-2MB Dedicated Video EEPROM (Two banks of 1 MB each, For tilemaps, possible 3D data)
-1MB Dedicated Audio EEPROM (For sequences and samples)
-1MB Dedicated Extra EEPROM (Could be used for game stats, physics object storage, etc)
-128 MB internal DataFlash for application and data storage
-PC-Connectivity through USB (obviously), planned NetPlay over PCs with active internet connection

These are some of the main points of my system. Each memory Bank can be accessed simultaniously by the propeller to fully utilize the multiprocessing and object-based coding.
Now, I do not claim to be the best at designing PCB layouts! (or systems, for that matter)·I am not an EE, I'm actually an ME with several years of controls system experience, but I have been a programmer for years now. I referenced the Propeller Demo board while laying out my board.
I've posted a snapshot of my PCB layout for the system below. I've worked on it in my freetime for about a month or two now, and thought some feedback would be nice. I also included the .pcb file, which can be viewed with ExpressPCB from expresspcb.com, if you havent heard of it before.
I ordered two of these boards, as well as my first chunk of components (Prop chip and clip, mostly). I plan to order the last batch in about two weeks. (IE, next payday )

Any ideas, comments, suggestions?
Thanks,



Post Edited By Moderator (Chris Savage (Parallax)) : 3/7/2007 4:36:49 PM GMT

Forrest

Looks impressive. How about posting the full silkscreen layer - so we can see where all the components go.

Sachiel7

Here's an updated .pcb and jpg with some silkscreen info I added that should hopefully explain things a bit more.

The controllers are fed through a 16:1 MUX (my first time using one) and as such only require a few address lines and a data line to the prop.

The DataFlash ROMs are similar, they share the same Clock, Input and Output lines, but each have their own Chip Select pin connection to the prop as well.

Each of the 1MB EEPROM chips has its own pair of serial lines, so they can be accessed simultaniously.

I left a cutout in the·rear left of the board for the prop clip, it should fit exactly into the notch so the total board is a 3.8 x 2.5" rectangle. I might put a small dab of hot glue or something to keep the clip in place, if needed.

The system as a whole is planned to have its own OS/Menu system for selective loading of programs. At runtime the OS will load up the appropriate program image from DataFLASH to the 32K EEPROM, as well as copy the appropriate Video Texture, and Audio Images to the external 1MB EEPROM banks. It will then trigger a system reset to execute the program.

At the start of every external application, it will re-load the system OS/menu program into the 32K eeprom. When a return-to-system is desired, or if the system is manually reset or shutdown, the system will return to the primary menu application.

I also hope to include the ability to have NetPlay whilst connected to a Internet-enabled PC. The PC would need to be running a 'backburner' application that would trancieve data over the internet, as well as trancieve serial communications through the USB connection to the propeller.

There's alot of software implementation to do here, but I'm starting on it (somewhat)

I plan to purchase the Game programming for the propeller powered Hydra book to serve as a basis for my software design for this system.

Well, I'm off to work, but I hope this explains my concept a bit more,


Post Edited By Moderator (Chris Savage (Parallax)) : 3/7/2007 4:36:58 PM GMT

Dennis Ferron

That's really cool. Any plans for a chassis for it?

Sachiel7

Well, the Retrosys 1.0 I built last year (which was basically a BS2SX interfaced with an ezVid2.0 module from Multilabs and a SEGA Genesis controller) was housed in a standard black plastic project box from radioshack. I planned to take a similar approach with this model, but I do wish a custom designed enclosure would be more possible.

If anyone has any suggestions on a more custom enclosure solution, please suggest some ideas here!

Post Edited By Moderator (Chris Savage (Parallax)) : 3/7/2007 4:37:07 PM GMT

Dennis Ferron

Well here's what I plan to do with my Hydra, when I save up enough money for one: notice in the pictures, the Hydra stands on four metal stand-offs for legs? Well, my plan is to take those stand-offs and mount them upside down, so that they stick up in the air. Then I'm going to get 2 squares of plexiglass cut so that one goes on top of the standoffs (thus clearing the tops of the chips), and the other goes on the bottom of the circuit board, separated by some washers/spacers. I can cut holes in the top for the expansion card slot and controller slots. I figure it will look really cool with some small, cold-cathode fluorescent tubes lighting up the edges of the plexiglass.

Looking at your board layout, it looks like the same thing could work - you'd still have access to all the ports and it's clear so people can see inside, but still provides reasonable protection.

Sachiel7

Yes, I had thought about the possibility of a clear plexi case...maybe I'll still go that route.
You see the retrosys logo in my sig?
I've had the logo since the 1.0 model was developed. I had planned to make a illuminated logo to go on the top panel of the case, but didnt get to it the first time aorund.
I'm planning on it this time. On the back half of the PCB I've got a few LED headers to connect to the lit display, once I get it made.
I plan to get some nice bright blue led's and a red/yellow/green for the leader.
If I simply ethed it into lexan though....hmmm
You've definitially got my gears turning now...

Post Edited By Moderator (Chris Savage (Parallax)) : 3/7/2007 4:37:13 PM GMT

QuattroRS4

Looking at the PCB design·I am just wondering if you have had any noise issues - I have found that I have had to use heavy gound planing to counteract such issues - that said these were industrial applications.

Rgds,
Quattro

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'Necessity is the mother of invention'

JoannaK

As a pcb-designer I would recommend adding some (say 8 * 100nF) capacitors for power supply stabilization. Also I'd recommended on filling free area with ground plane. It may well be that this board don't need them, but it's usually better to play safe than risk having unstabile system.

crgwbr

All I can say is WOW! Not only is there 4Mb of storage on that board, but I can accutly see someone using it all. Microcontrollers sure have come a long way. Since the early days of BS1 (Not that the BS1 is bad or anything, just sayin').

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NerdMaster
For
Life

Sachiel7

Actually there's a total of 132.03125 MB on the board, if you count the on board DataFLASH, and the 32KB EEPROM. But yeah, the 4MB is primarily for runtime use, while the DataFlash is more for storage of applications and EEPROM data images.
JonnaK: I have a supply setup similar to the Prop Demo board, there's a capacitor or two in there, but I'll keep that in mind, especially if the board seems to be having issues. I havent had experience with ground planes, I'm not too sure how to put them in in the express PCB software, but I'll have to figure that out.

I'm supposed to get in two of these boards today, I'll post a pic and once I get my Prop I'll be able to comment on how its running.

Just out of curiosity, if I do have noise issues, is there any way I could apply my own makeshift ground planing?

I know I probably should have used SRAM instead of EEPROM for runtime memory, but my experience lies in serial communications and EEPROM primarily, so I stuck with what I knew.

Thanks for the feedback! (and the interest!)

Post Edited By Moderator (Chris Savage (Parallax)) : 3/7/2007 4:37:21 PM GMT

IWriteCode

And? Did you receive the two boards you were expecting? And how are the results? [noparse]:)[/noparse]

hinv

Hi Sachiel7,

Since you are using EEPROM, don't you have a good chance of wearing them out?

How do you plan on loading your data? Your data sets appear to be pretty large, I would guess since you have so much memory.

How much throughput are you getting to/from your main memory?

Thanks,
Doug