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PA Semi releases its chip

Welcome to our 1682M overlords
Mon Feb 05 2007, 10:21
JUST OVER a year ago, we told you the tech details of the PA Semi PWRficient chips. Back then, it was mostly a simulation, real silicon was a bit further out, but the simulation it showed did boot Linux. Today the chips are real and you can buy them.

PA Semi will sell you an evaluation board with a 1682M chip on it today if you want one, full volume will follow in Q4. The claims from 2005 were all met, and a new feature was added on top of it. There are 10 'alpha' customers with more promised in the telecom, storage, military/aerospace, embedded control and curiously game console space.

So, what is the 1682M? If you don't want to read the whole tech run through above, it is the first iteration of a family of multi-core PPC chips, this one being a dual core. It has a lot of system on a chip functionality, you need very little to make a complete computer as you can see from the Electra reference board below.


Each chip is a single FP piped PowerPC that can issue three instructions per clock vs 5 for the PPC970 family. It should be similar on Int and and a little better on FP though, a lot of this is due to the large caches. They are full 64-bit PPC, support virtualisation, and would do Alitvec but that name is copyrighted by Freescale. Instead they do 'VMA'.

The three parts run at a max wattage of 25, 15 and 10W for the 2.0, 1.5 and 1.0GHz parts respectively, with typical wattage listed at 13, 8 and 6W. The individual cores are said to have a 7W max and 4W typical power consumption at 2.0GHz.

PA Semi achieved some of this efficiency through very fine grained clock gating and fast varying voltages. A typical modern chip may have hundreds or even a few thousand gated clock domains, the 1682M has 25,340 of them, so they can control things on a very granular level.

Additionally the dynamic voltage control is a little more advanced than what you see in Intel or AMD chips, with the voltage dependent on temp, IR drop and load. It is much the same as the others only more dynamic and granular. The exact speeds depend on how fast the PSU can switch voltages, currently the chip is faster than any commercial PSU you can get your hands on.

For software, you can get Linux (2.6.17 and 2.6.18 kernels), QNX and Wind River OSes along with a number of tools so it should be fairly familiar to most developers working with this type of board. The short story is that there are pre-rolled OSes and tools for you to play with.

The new feature is on the networking side of things. There is now support for 2,5Gbps Ethernet/SGMII slots. This technically is not a standard but some customers have requested it. If you have 10Gb on board already, a quarter of that is not a big step. This runs over two wires and is aimed at in box applications.

In addition to the dual core part, there is a single core available, basically it is a dual core with one fused off. A true single core with a smaller cache, USB and SATA will follow late this year. The four core variant is on track for 2008 some time, and other variants will follow that.

The short story is that and you can buy them. The chips are at least as functional as promised in 2005 and met all the power and performance goals. Now it is time to move on to the next big thing from PA Semi. µ


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