Linley on Mobile
Stranger in an ARM WorldApril 9, 2012
Author: Linley Gwennap
The mobile market is dominated by a single instruction set, but a few unARMed vendors have started to make headway. While Intel has received all the attention, a small Chinese chip vendor has been flying under the radar with a homegrown MIPS processor. This new product from Ingenic, the JZ4770, is already shipping in an Android tablet computer: the Novo 7 Basic from Ainol. This seven-inch tablet sells for less than $100 in China, in part because of cost savings from using MIPS.
Ingenic designed its own CPU, which it calls XBurst, for its tablet processor. Implementing the MIPS32 (release 2) instruction set, this CPU uses a simple scalar design. It operates at 1.0GHz (1.2GHz at overvoltage) in the JZ4770, which is built in 65nm LP. The single-core JZ4770 should have performance similar to that of single-core Cortex-A5 processors running at the same speed. Although 1.0GHz Cortex-A5 processors are currently shipping from Qualcomm, they are built in 40nm LP—more than one full process node ahead of the JZ4770.
In addition to low cost, Ingenic designed the JZ4770 for low power as well. At 1.0GHz, the XBurst CPU uses 90mW, and the entire processor consumes less than 300mW, according to the company. By comparison, the 40nm LP version of Cortex-A5 uses more power than XBurst despite the process advantage. These figures should help mobile designers use smaller, lighter, and less expensive batteries with the JZ4770.
Compared with the cost of an ARM architecture license, Ingenic saved millions of dollars by choosing MIPS—savings it can pass on to its chip customers. Like Intel, Ingenic and MIPS are focusing on Android, because most Android apps are architecture neutral and run on any instruction set. For those apps that include native ARM code, MIPS is working with developers to generate MIPS versions, starting with the leading Chinese-language apps.
The JZ4770 is well suited to low-cost tablet computers. Its high level of integration includes nearly every feature required in such a device; system designers need only add memory and a Wi-Fi combo chip. The JZ4770 can also be used in e-readers and other mobile devices where cost is critical. Ingenic has already shipped more than 30 million application processors since 2005 and claims to have shipped “millions” of JZ4770 chips into Android tablets. This success shows that the tablet market needs a low-cost supplier.