I was reading about System on Chip on wikipedia and I was wondering

Is the iPhone an example of this? Is the system saved on a processor? How is the system actually put on the device? Thanks!


Instead of "System on a Chip", think instead of "PCB on a Chip".

Consider if you wanted a system with an audio codec, a 1MB SRAM, a microcontroller, an Ethernet connection, a USB connection, an ADC, and a DAC. Normally you would have to design a PCB for this, route all the connections, probably need six or eight layers (depending on size and stackup).

The SoC would just combine all those discrete chips into one monolithic "System" on a chip. This simplifies board design, since you don't have to route all those connections on the PCB. It also reduces component count (no need for series terminating resistors, probably fewer bypass caps, etc). It also reduces component size, since one SoC will be physically smaller than the sum of individual chips.

Software runs on an SoC like pretty much anything else. Software gets written and compiled to target the SoC's instruction set architecture, the compiled machine code gets loaded into memory, and the SoC does its fetch-decode-execute thing.

  • \$\begingroup\$ I'm trying to make a mobile device that has no screen, a bare rtos, that is able to respond to button touches, from scratch (nothing like arduino). Would this be something to look into? \$\endgroup\$ – Coder404 May 3 '12 at 22:29
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    \$\begingroup\$ @Coder404 - No, designing and making an SoC costs approximately one bazillion dollars. \$\endgroup\$ – Rocketmagnet May 3 '12 at 23:00
  • \$\begingroup\$ @Coder404 - Using an SoC with (an ARM Cortex-M3 would probably be great for your RTOS application) is a great idea. However, as Rocketmagnet points out, designing and making one yourself is not a good idea unless you plan to sell more than about 500,000 devices (I think that's a more accurate estimate than the 'bazillion' number; it really only costs a couple million). \$\endgroup\$ – Kevin Vermeer May 3 '12 at 23:19
  • \$\begingroup\$ Wait...so a SOC is something prebuilt? I'm still not fully understanding the concept \$\endgroup\$ – Coder404 May 4 '12 at 0:15
  • \$\begingroup\$ @Coder404 Yes, it's something prebuilt. There already are SoCs with popular components and you can just buy them and use them in your own product. Some manufacturers won't talk to you unless you can buy large enough quantities but for some systems on a chip, you can buy individual units from usual distributors. It's basically like buying a prebuilt PC. PC manufacturers just preselect components, integrate them and instead of buying everything separately, you buy one product. \$\endgroup\$ – AndrejaKo May 4 '12 at 5:14

No, and iPhone has many chips. However one of them that includes the ARM processor and some peripherals (clock generation, USB port, memory controller, for example) would be.

I see you tagged this PSOC. That's a particular brand of SoC.


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