XScale is Intel's implementation of the fifth generation of the ARM architecture based on the ARM v5TE instruction set without floating point instructions. The XScale processor family belongs to the group of RISC processors. It is mainly used in PDAs , portable DVD players and in the embedded area. XScale has been part of the Marvell Technology Group since 2006 .
As part of a legal dispute between Intel and the semiconductor division of DEC , Intel acquired rights to the ARM architecture and its StrongARM microcontroller line. With this, Intel initially sought to replace its line of outdated RISC processors ( i860 and i960 ), which was collapsing in sales . The term XScale, created later, describes nothing more than Intel's continuation of processors and controllers of the ARM line.
There are four generations of XScale processors: PXA210 / PXA25x, PXA26x, PXA27x and PXA3xx.
Common features of all XScale processors
All generations of XScale are 32-bit ARM v5TE processors manufactured with a 0.18 µm process and have a 32 KB data cache and a 32 KB instruction cache . They also all have a 2 KB mini data cache.
The PXA210 was Intel's entry-level XScale designed for cellular applications. It came on the market at the same time as the PXA250 in February 2002 and was available with 133 or 200 MHz.
The PXA25x family consists of the PXA250 and PXA255.
The PXA250 was Intel's first generation of XScale processors. It was available with three clock speeds: 200 MHz, 300 MHz and 400 MHz. It came out in February 2002 in chip version A. But also the second version B was fraught with various errors that had to be corrected with extensive bug fixes in the software.
The PXA255 came out in March 2003 to replace its predecessor and was planned as chip version C of the PXA250. The main difference was a doubled internal bus speed (from 100 MHz to 200 MHz) for faster data exchange and a lower operating voltage (only 1.3 V at 400 MHz) to reduce power consumption.
The PXA26x family consists of the PXA260 and PXA261-PXA263.
The PXA260 is a stand-alone processor with the same clock speed as the PXA25x, but the case is 53% smaller.
The PXA261-PXA263 are identical to the PXA260, but have additional internal memory in the processor. 16 MB 16-bit StrataFlash memory in the PXA261, 32 MB 16-bit StrataFlash memory in the PXA262 and 32 MB 32-bit StrataFlash memory in the PXA263. The PXA26x family came out in March 2003.
The PXA27x family (codenamed Bulverde) consists of the PXA270 and PXA271-PXA272 processors.
The PXA270 is available in four different clock rates (312 MHz, 416 MHz, 520 MHz and 624 MHz) and is a stand-alone processor without integrated memory.
The PXA271 has four different clock rates (13 MHz, 104 MHz, 208 MHz and 416 MHz) and has 32 MB 16-bit StrataFlash memory and 32 MB 16-bit SDRAM in the same housing.
The PXA272 can be clocked at 312 MHz, 416 MHz or 520 MHz and has an integrated 64 MB 32-bit StrataFlash memory.
Intel has added several new functionalities to the PXA27x family:
- Wireless SpeedStep : to save power, the processor automatically clocks down depending on the processing load.
- Wireless MMX : 43 new SIMD commands that contain the full MMX command set and the integer commands from Intel's SSE command set along with some commands that are unique to the XScale. They are used to increase the speed of encoding and decoding multimedia as well as playing games.
The PXA27x family was launched in April 2004. Together with the PXA27x family, Intel has released the 2700G embedded graphics coprocessor.
In August 2005, Intel introduced the successor to the Bulverde PXA270 processor, codenamed Monahans. The new Monahans processor was operated at 1.25 GHz. Intel stated a performance increase of 25% compared to the Bulverde processor (800 MIPS for the 624 MHz PXA270 processor compared to 1000 MIPS for the 1.25 GHz Monahans). The successor to the 2700G graphics processor with the code name "Standwood" has been discontinued by Intel. Some features of the Standwood graphics processor are already built into the Monahans processor. If additional graphics functionality is required, Intel recommends the use of third-party products, such as the Nvidia GoForce chip family .
The processors of the PXA3xx series from Marvell Semiconductors have been commercially available since November 2006 .
With XScale processors, up to 128 MB of the StrataFlash memory specially developed by Intel for mobile use can currently be addressed directly. Up to 256 MByte (with the PXA270 up to 1 GByte) can be controlled on SDRAM. In addition, 64 Mbytes of address space are available for slow I / O devices or fast SRAM; this address space can be increased at the expense of the connectable flash (in 32 Mbyte steps).
Applications of the XScale
The XScale microprocessor is used in numerous PDAs, such as the Palm Tungsten C or the Dell Axim X50 and X51 . The XScale is also used in portable media players (portable video players) such as the Zen .
Some companies offer modular systems or single-board computers (SBC) with processors from this family, making the architecture usable for industrial applications. These manufacturers usually also offer CPU modules for evaluation (EVMs for short) and Board Support Packages (BSPs) with application examples to make it easier for potential customers to start developing their own solutions.
Sale of the business division
On June 27, 2006, Intel announced the sale of its communications and application processors business to the Marvell Technology Group for the equivalent of $ 600 million at the time of sale. After the contractually agreed five-month transition period has now ended, Marvell has now presented the next generation of processors. The new generation PXA3xx is therefore no longer manufactured by Intel.
- Intel XScale® Core - Developer's Manual (PDF; 3.6 MB)