Several articles on the Web today are discussing some new name changes to the Qualcomm line of Snapdragon mobile application processors to clarify the differences in the choices and to show a bit of the family’s future roadmap. Qualcomm now groups the Snapdragon line into four classes, with each class having different CPU cores, different clock rates, and different sets of peripheral subsystems. The first three classes (s1 through s3) are in production. Members of the s4 class, manufactured in a 28nm process, are said to be sampling now. Each class contains several members of the Snapdragon family.
The following chart shows how Qualcomm is now classifying its Snapdragon application processors.
Most of the members of the s1, s2, and s3 classes incorporate one or more CPUs based on Qualcomm’s proprietary microarchitectural implementation of the ARM v7 instruction set. The resulting Qualcomm-specific processor core—named Scorpion—is said to resemble the ARM Cortex-A8 processor core. (Note: the four MSM7xxx members of the s1 class appear to be based on an ARM 1136ES-J CPU core that implements the ARM v6 instruction set and run at clock rates to 1GHz. See http://en.wikipedia.org/wiki/MSM7000.)
Members of the Qualcomm Snapdragon s1 class are manufactured with a 65nm process technology and are designed for less demanding applications. These mobile application processors have one CPU core operating at clock rates of several hundred MHz to 1GHz, may have an Adreno 200 GPU, and support stereo sound and 3G wireless telephony. The Adreno 200 GPU is based on the Imageon GPU technology Qualcomm obtained from AMD in 2008.
Members of the Qualcomm Snapdragon s2 class are manufactured with a 45nm process technology and therefore deliver more performance. They each have one 1.4GHz Scorpion CPU and a more powerful Adreno 205 GPU. In addition, they include a video display subsystem capable of decoding 720p HDTV streams and a Dolby 5.1 audio decoder. Each click of the manufacturing dial allows Qualcomm to add more and more powerful IP subsystems to the Snapdragon mix.
Members of the Qualcomm Snapdragon s3 class are also manufactured with a 45nm process technology but are taken from the right side of the process curve so that their dual Scorpion CPUs run at 1.5GHz and the HD video decoder can handle 1080p video. There’s also an even more capable GPU.
Qualcomm is reportedly sampling single-core members of its next-generation Snapdragon s4 parts that are/will be even more capable than preceding members. Members of the Snapdragon s4 class incorporate one or more copies of a next-generation version of the Scorpion processor called Krait.
All of these mobile application processors are terrific examples of SoCs designed with the concepts of System Realization and SoC Realization well in mind. Qualcomm’s Snapdragon series is based on the company’s implementation of the ARM v7 instruction set using an IP processor core named Scorpion that Qualcomm developed or with the next-generation version, Krait. The GPUs for these parts are based on IP that Qualcomm acquired from AMD, which got the IP when it acquired ATI in 2006. You can be sure that there are other standard IP blocks shared across these parts as well.
Applications processors like the Snapdragon family are the 21st-century equivalent of microcontrollers. They lack the inclusive memory aspect of early microcontrollers because the tasks and large operating systems being assigned to the 32-bit CPU cores need more bulk memory (DRAM and NAND Flash) than earlier embedded designs that used 4-, 8-, and 16-bit microcontrollers. The I/O peripherals have also gotten much larger and more complex. We’re not driving simple LEDs or vacuum-fluorescent 1- and 2-line alpha displays any more. We’re driving large graphical LCDs and electronic ink displays with integrated touch screens instead. Similarly, simple parallel ports and UARTs have given way to USB and Ethernet ports and their significant software driver stacks and middleware. Nevertheless, these applications processors fill the same sorts of niches as microcontrollers of the past, but for more ambitious embedded end products.
Note: This blog entry is based on several Web resources including the following articles:
Qualcomm renames SoCs, quad-core on track by Rick Merritt at EETimes.com
Qualcomm renames Snapdragon, gears up for quad-core showdown with NVIDIA by Andrew Kameka at Androica.com
Qualcomm’s Updated Brand: Introducing Snapdragon S1, S2, S3 & S4 Processors by Anand Lal Shimpi at Anandtech.com
Tip of the hat to Denny George for additional info on low-end s1 devices.