superUzebox idea

[kamiro87]

I was wondering if there would be interest in developing a "super UZEbox" around a 32-bit SOC.
I was thinking that something with the capabilities somewhere between the SNES and the game-boy advance.

there are a bunch of interesting SOCs out these days, some of the real nice ones have things like integrated ethernet mac/PHYs, usb OTG, bus interfaces. some possible contenders could be microchip's pic32 or an arm from luminary micro. both of which are cheep enough and pack enough power to make interesting platforms. (GCC support for bolth)

one chip that i'm particularly impressed with is the 9000 series from luminary micro. i've looked at the schematics for their LCD reference design and that little chip packing some impressive hardware. (SDRAM interface, mac/PHY, USB, cortex M3, i2S audio!)
http://www.luminarymicro.com/products/rdk-idm-sbc.html

Another interesting chip would be microchips pic32. I've used these chips in robotics projects and they're nice to work with. pic's ICD is annoying but with a USB boot-loader firmware its not that bad. one feature that would be particularly interesting is using the PMP port with an r2r DAC and some DMA to get higher resolutions.

[paul]

There has been considerable interest in such a venture, but it really needs someone to lead the way before anything would happen. I imagine it would be a fairly long process, considering most of us aren't wealthy enough to do this full-time Chris (lightfoot) and scuzz have both shown interest and I think scuzz may be working away on some kind of upgrade or expansion.

[TonyD]

There has been considerable interest in such a venture,

Looking through the forums its been discussed many times. The main threads I remember are:

The Crazy Ideas
XDreamMegaStationUzeBox?
ATmega1284P update
Uzebox inside an FPGA ?

It seem to come down to either a AVR32 or a ARM as a possible upgrade, with the ARM being the device people most talked about.

The previous ARM's mentioned were the ARM Cortex-M3 from ST STM32 (512K Flash, 64K SRAM, 80Mhz) and the NXP 1700 (512K Flash, 64K SRAM, 100Mhz). I've also mentioned the Cypress Cortex-M3 PSOC5 (256K Flash, 64K SRAM, 80MHz, CPLD) as well

Clay and I talked about other more exotic multicore chips from Xmos (XS1-4G) and Rapport (Kilocore256).

[uze6666]

One important thing to think of is the "hobbyist trade-off factor". I've always seen that as an important factor in the relative success of such project. If nobody can build it or easily understand or program it, it looses appeal since otherwise why not just buy a commercial console? And let's face it, Ladayada's Fuzebox is a big part of the success or the Uzebox, specially because it's a kit and almost exclusively uses though hole parts. Seems like everybody is making a game console lately (yet it's awesome to see how far electronics have come to enable the average hobbyist to do that.) so it's even harder to get your project noticed. It's such a small niche market, you must have something the other doesn't. Because most can "easily" build powerful consoles with the latest ARM chips, I opted for a balance of power vs. simplicity by using the mega644 and it made it challenging enough for geeks and freaks to push it to the limit.

So perhaps a SuperUzebox is an oxymoron since the project was meant to be simple and not super?

-Uze

[scuzz]

Yeah, as mentioned I have been working on a "super uzebox" based around a 32 bit arm7. My main thing has been trying very, VERY hard to make it as hobbyist friendly as possible, which is difficult when you start with the words "Well the main CPU is a 144 pin LQFP!" That being said I made sure that all the chip resistors and capacitors have been 0805 (which is nice and big, as far as chip resistors go). That being said this is going to have to be pitched more as "Uzebox for those who want to spend a few hours soldering".

I'm also trying to make sure that I don't move too far away from some thing that I consider important parts:
1) It still outputs to TV because if it doesn't it's not exactly retro anymore, and getting things on your TV with the thing is practically half the fun!
2) Though there are a few extra fun chunks (like I put in space for an audio DAC and a bunch of other little things you can choose to use the audio DAC and other features with jumpers), the actual final product will only need three chips: CPU, RAM, and NTSC chip. The RAM is because I hope to be able to do a "load video game from SD card fully into RAM and then run the chip at full speed" type thing. And if in the future this moves to a "loading screen when swapping out massive sound files" type thing then so be it, but for now I'm keeping it simple.
3) It has to be as hobbyist friendly *as possible*. This isn't something that's particularly friendly by nature (as already mentioned) but I can try! One more thing I'm doing to try and keep the friendliness level very high is that this is all being designed in Eagle CAD, but it's all on a 2-layer board in order to make sure that anyone can edit it using the free version of the software.

That being said all of this has kind of taken a back seat while I'm trying to finish my work in the real world! This robotic arm we've been building is nuts and has a million tiny considerations not the least of which is that it will be operating at something like 6km underwater so I've been kind of absorbed in making sure that everything is as it should be.

The schematic for the Arm-based uzebox is pretty much done, but I wasn't sure whether or not the chip I've chosen is capable of accessing its ram real time due to the fact that it only has an 8bit wide bus and can't due burst reads, so I was thinking that I may want to bump it up to the 200Pin LQFP which has a 32bit wide data bus so that I can run all code off of RAM in real time, and leaves a LOOOOOOOOOOOT of room for expansion if the project goes well . Anyway, I'll start posting a lot more about the project as development gets more underway than just "mostly planned."

Does anyone who's a bit more versed in ARM design know if the LPC2388 can execute code in external RAM in real time? The datasheets for the LPC2388 are here.

[uze6666]

That's very interesting, I love the Arm7tdmi as I used to do Gameboy advance development a few years ago! As far as for the GB, only the internal work ram could run at full speed, the external had some wait states (but again that's for the gameboy advance). Sure, 144 pins SMT is a bit intimidating for newbies, but while being at it I'd go with the 200 pins and allow full features and the fastest RAM access as possible. How much ram were you intending to put in there (I guess static RAM)?

-Uze

[scuzz]

I was planning on only putting about 1 megabit originally (because that was the limitation for the addressing lines on the LPC2388). But for the 200pin package I wasn't too sure. It should be cheap, so basically whatever I can find which is cheap on digikey! Essentially I was only planning on having it be a couple of Mb at best, but I could probably find a family which had the same pinout but a bunch of different sizes. It could theoretically be as much as 512Mb, but that seems excessive...

Yes static ram (also asynchronous, no burst reads).

Glad to hear you're interested Uze

I should mention that the 200 pin chip is the LPC2478.

[TonyD]

Scuzz this sounds like a cool project in the making

Have you considered ARM's newer Cortex-M3 architecture from NXP/ST/TI instead of the ARM7 architecture. They have pretty much the same memory configurations and I/O but usually have faster clocks where 80Mhz is the norm with the NXP chips clocking in at 100MHz.

The reason I suggest this I found that the early NXP LPC21xx ARM7 chips had very slow digital I/O. I designed and built a small eval system using the LPC2106 a few years ago (see here) and wasn't able to toggle the digital I/O much faster than ~1.5MHz on a design with a 60MHz clock.

I'm pretty sure the NXP would have fixed slow digital I/O with their newer range ARM7 LPC23xx but its something worth checking out before you commit your design to using the LPC2388.

Keep us posted.

[scuzz]

Scuzz this sounds like a cool project in the making

I hope so!

Have you considered ARM's newer Cortex-M3 architecture from NXP/ST/TI instead of the ARM7 architecture?

I hadn't! I'd really picked the CPU pretty arbitrarily. The main important features were that it came in an LQFP and that it had a bunch of neat features (the big ones being built-in SD/MMC card interface as well as the ethernet port). The reviews of the chip were quite good, and I could glean what extra design information I needed off of boards produced by various companies like Olimex.
That being said the price point on a fully-featured cortex-m3 is $6 cheaper then the LPC2478 I had been looking at, and price is a definite consideration. Taking a quick glance at the datasheet for the LPC1768 there seems to be no external memory controller... so I guess I'll have to poke around a bit on these to actually pick one (that being said I should probably do some hefty research before I make any decisions but as previously mentioned this is a bit back burner until the end of the month at best).

... slow digital I/O... wasn't able to toggle the digital I/O much faster than ~1.5MHz on a design with a 60MHz clock...

1.5MHz is pretty fast for what we're doing! What would I need to do for an Uzebox even close to that kind of switching speed? The fastest switching things on the console look like controller inputs, audio, and video, and I think those are pretty well clocked under that, aren't they?

Keep us posted.

Will do. Glad to have others interested in the project.

--EDIT--
I almost forgot that I would really like USB on this if for no better reason than lower the barrier for debugging. As great as a full-blown emulator is that's dependent on someone building it first!

[TonyD]

When I moved from ARM7 to the Cortex-M3 a year or so ago, I switched from NXP to ST and used their STM32F103VE - 512K Flash, 64K RAM, 72MHz, 5V tolerant I/O lines, an external memory interface on the 100 and 144 pin parts and USB i/f but no Ethernet, all for about $16. They have a really cool eval board called Primer 2 for ~$100. Too many cool features to mention but check it out here.

After reading your post I check the prices for the NXP1768 (~$10) and they are really cheap compared to other ARM7 and Cortex-M3's - NXP must be pushing them hard.

If you drop the requirement for built-in Ethernet and consider using an external Ethernet module such as WIZ811MJ you could use either the LPC1768 or STM103FVE with both available in a more hand soldering friendly 100-pin TQFP