Supported Chip features accessible

[Dealerz]

I've done some work with OMAPS in the past and was curious if some of the hardware features that currently aren't being used was made accessible on the PCB, as an example the camera image signal processing (ISP). I've also done work with GSM/GPRS systems so I would be curious if you also made an I2C or an SPI signal available as well for integration purposes.

One other question, more on the hardware design side, I was wondering why you went with on board SDRAM chip design rather than a removable chip so if somebody wanted to upgrade the memory they could just buy more ram? The chip supports up to 1G and since you are using Linux it wouldn't be too hard to increase the memory access. I'm just curious as to what made you go the route you did.

 

[PandoraNoHako]

I was wondering why you went with on board SDRAM chip design rather than a removable chip so if somebody wanted to upgrade the memory they could just buy more ram? The chip supports up to 1G and since you are using Linux it wouldn't be too hard to increase the memory access. I'm just curious as to what made you go the route you did.

They didn't went with it, and didn't go the route. It was Texas Instruments who did. They only sell the chip and memory together:

The OMAP SoC and RAM are sandwiched together in what is called a package-on-package (PoP) configuration.

Once the pieces are fitted together, they are encased in plastic and are, for all intents and purposes, a single unit.

When the first Pandora boards were built, compatible 256MB SDRAM packages were not available in commercial quantities. I do not know if TI is even now shipping OMAP 3530 chips with 256MB packages installed.

If you need further details, use the search function (on both boards) as it has been asked and discussed several times before since for some reason there are always people showing up who think that 128MB will not be enough.

 

[Dealerz]

I think 128mb is fine but what I'm actually referring to is the external SDRAM controller that's available on the chip. Now I had thought the 128meg was external, I didn't know that they where referring to the internal ram on the chip so I apologize for that miss understanding. However, since the chip supports an external SDRAM controller is this made available? This feature allows you to extend the memory on the device and it would have been cool if they would have made this available so people could add more RAM if they wanted to. As well as other features the chip supports like the ISP.

 

[gruso]

Check out this thread: http://www.gp32x.de/board/index.php?showtopic=43063

And also search gp32x for posts by MWeston. He's the hardware designer.

 

[mali]

MWeston:

No, no, you guys have it all wrong.

There are eight chip selects, but only two can be used for SDRAM control. Those are the only ones you would really want to use for memory. Adding 128MB of SRAM on a chip select would be super expensive, take up a huge amount of board space and suck back the power like Pepsi cola.

So basically we have two chip selects for practical memory addition. Each chip select can decode up to 512MB of memory (remember addressing is not linear but based on row/column decoding).

This means that OMAP3 can handle up to 1024MB of DDR-333 memory which is fantastic for an embedded device like this, but stackable memory at that capacity isn't available yet and I don't even know when or if it will. Of course, we can buy regular DDR memory that could go on the PCB and add up to 1024MB, but the Pandora PCB has no room for it and still have over 50 buttons plus a bunch of connectors all over the place and still be close to DS-sized. The solution would be to add another PCB with the high speed stuff and stack it on the board, but that would cut the battery size in half and that goes against what we want for this system.

 

[Dealerz]

Thanks for the response I'll check out the link too for more information.

 

[torpor]

If you really need a *lot* of memory, there is always /swap. Put a nice fast SDHC 32-gig card in, and let 'er rip ..

 

[Chip]

I've done some work with OMAPS in the past and was curious if some of the hardware features that currently aren't being used was made accessible on the PCB, as an example the camera image signal processing (ISP). I've also done work with GSM/GPRS systems so I would be curious if you also made an I2C or an SPI signal available as well for integration purposes.

Everything that could be made available for hardware hacking has been:

All of the connections made to the processor are documented in the source code so you will know what every pin does. These chips use via in pad technology and all the high speed stuff is sandwiched in the board between multiple plane layers so you couldn't actually scratch off the mask and start probing the signals anyway.

I will have a termination point for every signal I was able to fan out from the processor, implemented or not and all connectors and headers for the entire Pandora will be documented and freely available; Subject to that "at your own risk and voided warranty" clause of course.....

Link to original post. Link to a high res pic of the board where you can see the various solder pads that allow access to these points. Obviously there wasn't room to label them all on the PCB, but as Michael says, everything will be documented when the Pandora ships. Hack away.

 

[Dealerz]

Thanks chip for the info. I've found the links to the gp32x forum and have been reading up on that. I got lucky and made it on the first batch and am looking forward to seeing this.

I have an old TI dev board for the OMAP3503 for an old contract it didn't have the DSP core in it, and any 3d stuff so I'm really looking forward to seeing this beast. I need to pull out my old TMS320 stuff and do a little review. Also got to pull out my old TI FAE's business card and call him up again, which should make him happy...

Good work and looking forward to seeing more in the future.

 

[billix]

[...] Link to a high res pic of the board where you can see the various solder pads that allow access to these points.

Why are the chip markings all covered in this picture?

 

[parag0n]

When that photo was taken, pretty much all the chips on-board were under NDA