Friday, October 23, 2009

ARM Cortex A5

On October 21 ARM announced a new CPU design at the low end of their range, the Cortex A5. It is intended to replace the earlier ARM7, ARM9, and ARM11 parts. The A5 can have up to 4 cores, but given its positioning as the smallest ARM the single core variant will likely dominate.

To me the most interesting aspect of this announcement is that when the Cortex A5 ships (in 2011!) all ARM processors, regardless of price range, will have an MMU. The older ARM7TDMI relied on purely physical addressing, necessitating the use of either uClinux, vxWorks, or a similar RTOS. With the ARM Cortex processor family any application requiring a 32 bit CPU will have the standard Linux kernel as an option.

Story first noted at Ars Technica

Cortex A5


In the comments Dave Cason and Brooks Moses point out that I missed the ARM Cortex-M range of processors, which are considerably smaller than the Cortex-A. The Cortex-Ms do not have a full MMU, though some parts in the range have a memory protection unit. So it is not the case that all ARM processors will now have MMUs. Mea culpa.