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I am looking for SOCs with integrated memory to avoid having to worry about design of a memory bus for, what is supposed to be, a pretty low power application. I'm looking for something like the raspberry pi where the ARM core and the memory are integrated into a single chip, but my searches have yielded nothing. In fact, when I look up the SAMSUNG K4P4G324EB processor that the RPi actually uses, all I get on Samsung's website is a big set of applications processors with off chip memory.

Does anyone have any resources or locations I can go to get a decent ARM SOC with around 512MB of integrated memory?

Dabloons
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  • why can't you do chip on chip? – hildred Dec 13 '13 at 21:05
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    The Raspberry Pi **does not** have memory integrated into the MCU. The memory is on a separate chip that [attaches to the "back" of the MCU package](http://en.wikipedia.org/wiki/Package_on_package). – Ignacio Vazquez-Abrams Dec 13 '13 at 21:08
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    RPi MCU uses a Package-on-Package(PoP) form factor where the memory is physically placed on top of the MCU package. – dext0rb Dec 13 '13 at 21:09
  • The RPi chip is by Broadcom (BCM2835) and K4P4G324EB is the RAM part stuck on top. – pjc50 Dec 13 '13 at 21:14
  • Oh... well good lord, I have never even heard of that. How in the hell do I design for that? I can't route traces on chip? Can I? – Dabloons Dec 13 '13 at 21:17
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    Microcontrollers with on-chip RAM top off at 32 **KB**, as far as I've seen. There may be a few that are larger but I doubt they get above 1MB, let alone 512MB! – DoxyLover Dec 13 '13 at 21:28
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    @Dabloons There is no routing for you to do - the chip simply fits over the SOC and is soldered in place. The memory pinout just needs to be compatible. – dext0rb Dec 13 '13 at 21:29
  • Why in the world do you need 512 *megs* for a "low power application"? – Igor Skochinsky Dec 13 '13 at 21:55
  • @IgorSkochinsky - "Low Power" may me running a fancy web-server off 1W of power, rather then using a full-on PC. It doesn't have to mean nanowatts or running off coin-cells... – Connor Wolf Dec 14 '13 at 06:11
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    Why not go for an embedded pc that already has all the components done for you? A RPI, Beagle Bone Black, or a Pogoplug/Sheevaplug type deal? – Passerby Dec 14 '13 at 10:42

2 Answers2

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Some FAE explained this to me a few years back like this:

The process for fabricating DDR memory is a completely different one than the one used for the processing unit. Also, the average life time for a DDR2 IC or DDR3 IC or whatever DDR IC is much shorter (~ 3-5 years) than the availability for the processor (10-15 years). So even if they build this package-on-package IC they couldn't guarantee the lifetime, thus reducing their marketing point.

I know what you mean, laying out the DDR2/DDR3 interface is an error-prone task and requires some very low level software digging - I personally do not like that as well.

Tom L.
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Microchip expanded some previously Atmel MPUs ATSAMA5D2x with DDR2 or LPDDR2 in a package as SiP:

https://www.microchip.com/design-centers/32-bit-mpus/sip-som/system-in-package

Currently is there memory between 16MB DDR2 to 256MB LPDDR2

Yes, it is not 512MB but for some one who plan to use this for IOT thinks with running Linux it can be enough.

vlk
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    If you need 512MB and more you can also look at [Samsung ARTIK](https://eu.mouser.com/new/samsung-artik/samsung-artik-modules/) modules or [Octavo Systems SiP](https://eu.mouser.com/new/octavo-systems/octavo-systems-osd335x-sm/) – Andrejs Gasilovs Dec 15 '17 at 08:39