[Newbie] How to identify the SoC...

Hi,

I am new to Raspberry Pi group. I received RPi yesterday. I am looking at the board and the diagram below (which is taken from ). I am trying to identify the SoC on the board I received. From the below diagram, it seems the SoC should be the big rectangular black square(the chip) at the centre of the board. And that is Broadcom's SoC BCM2835. Now, I am not a hardware person so my understanding is quite limited in this case, but I was expecting some labeling on the chip which indicated that it was BCM2835. Instead the board I received has the label Samsung K4P2G324ED. I did a web search and found that the K4P2G324ED is a Mobile DRAM (http://www.samsung.com/global/business/semiconductor/product/mobile-dram/detail?iaId=747&productId=7611). So how do I tell just by looking at the board that the SoC is Broadcom BCM2835? Sorry, if this sounds stupid but I am new to Raspberry Pi.www.element14.com/.../RasPI (2).jpg

Thanks and regards,

~Plug

johnbeetem over 12 years ago

The BCM2835 is under the Samsung SDRAM chip, using a technology called Package on Package (PoP). Here is a photo of the SDRAM (left) and BCM2835 (right) on jamesh's finger: raspberrypi.org. You're looking at the board side of each chip. The flip side of the BCM2835 has a land grid array (LGA) that corresponds to the ball grid array (BGA) on the SDRAM.
PoP has two advantages: it takes up less circuit board space (very important for cell phones) and the wires between the SoC and the SDRAM are very short which improves speed and saves power. The disadvantage is that they're hard to manufacture and rework, especially with very dense BGAs as above.

Edit: there's a nice list describing each of the major RasPi components at the RasPi Hardware Wiki: http://elinux.org/Rpi_Hardware#Components. The above BC2835 PoP description is an expanded form of the Wiki.
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Former Member over 12 years ago in reply to johnbeetem

Thank you very much John for the picture!

Kind regards,

~Plug
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