SOC it To 'Ya!

A host of system-on-chip silicon devices will help push embedded Linux into the post-PC era.
A Post-PC SOC Checklist

Here's my checklist of minimal requirements for a post-PC SOC:

  • 32-bit CPU

  • Built-in interface to RAM and ROM

  • Built-in DMA, interrupt and timing controllers

  • Built-in interface to disk or flash memory

  • Built-in Ethernet and/or LCD/CRT interface

  • Built-in serial and parallel ports and/or USB

  • Full embedded Linux support

Why require either built-in Ethernet or a display controller? That's because some SOCs go in “black box” devices that don't need displays, such as firewalls, specialized servers or gateways, while others go in user-interactive devices like web pads and vending machines. By including at least one of these two popular external world interfaces, the SOC implements all the key functions of the required embedded computer.

Are there any SOCs that currently meet all the requirements on my checklist? You bet! For several months, I've been gathering info on post-PC Linux-oriented SOCs. Here's a sampling of what I've found.

  • STMicroelectronics STPC Industrial—contains an 80MHz x86 CPU, plus a CRT/LCD display controller, PCMCIA and serial/mouse/keyboard ports. The STPC Consumer is another version, with a slightly different mix of features.

  • Motorola PowerPC MPC823e—contains a 75MHz PowerPC CPU, a sophisticated communications signal processor, plus a CRT/LCD display controller, PCMCIA, seven serial ports, USB, I2C and SPI.

  • IBM PowerPC 405GP—contains a 266MHz PowerPC CPU, plus 10/100 Ethernet, serial and parallel ports and I2C.

  • NETsilicon NET+ARM—contains a 40-MIPS ARM7TDMI CPU, plus 10/100 Ethernet, two high-speed sync/async serial ports with HDLC and SPI support, four IEEE-1284 parallel ports and 24 digital I/O pins.

  • Aplio/TRIO—contains a 20-MIPS ARM7TDMI CPU, a pair of 40-MIPS DSPs, plus two serial ports, SPI, a pair of CODECs, 10/100 Ethernet, USB and Flash memory interface. The DSPs and CODECs provide software modem, audio and voice functions.

  • Axis ETRAX—contains a 100-MIPS RISC CPU, plus 10/100 Ethernet, IDE, SCSI, two IEEE-1284 parallel ports and four high-speed serial ports.

  • Intel SA-1110—contains a 206MHz StrongARM RISC CPU, plus an LCD display controller, four serial channels, IRdA, USB slave and 48 digital I/O lines.

  • NEC Vr4181—contains a 66MHz 64-bit MIPS RISC CPU, plus interfaces for LCD display, CompactFlash, a serial port, IrDA, keyboard, USB, touch panel and audio in/out.

Bear in mind, this list represents the tip of the SOC iceberg. New SOCs are announced continually, so check for the latest information at Use the site's search function, with “system-on-chip” as the keyword.

The post-PC era is just around the corner and there's little doubt that embedded SOCs, combined with embedded Linux, will be two of its principal enablers. So get ready for some exciting changes in the electronic gadgets that surround us, as those devices become much more intelligent and much more connected.


Rick Lehrbaum ( created the “embedded Linux portal”, which recently became part of the ZDNet Linux Resource Center. Rick has worked in the field of embedded systems since 1979. He co-founded Ampro Computers, founded the PC/104 Consortium and was instrumental in launching the Embedded Linux Consortium.