TI’s new Cortex-M4 line versus the rest

Recently I received an email from Texas Instruments (TI) in which they announced the availability of their new Cortex-M4 line. I really like many products TI makes. When I spoke to TI people at Nürnberg’s Embedded World fair last March, I was thrilled to hear TI would release a Cortex-M4 part in autumn 2011.

I have used their LM3S9B96 processor and am very satisfied with it – excellent peripherals, very good DMA controller, lots of memory and the inclusion of Stellarisware and SafeRTOS in ROM in the chip. I sort of expected the extension of their Cortex-M3 family with Cortex-M4 based microcontrollers that would be faster and  just as well, or better, equipped. To my disappointment, that is not the case:

  • The new Cortex-M4 line (Blizzard) is not faster than the Tempest class Cortex-M3.
  • The new Blizzard class has less internal memory (32K vs 96K).
  • The new Blizzard class has no external bus interface.
  • The new Blizzard class has no Ethernet MAC/PHY like the Tempest class.

The only things going for it seem to be the internal EEPROM, the DSP additions in the core and the fact that the IC is produced using a 65 nm process.

So, why would I use the new Blizzard class instead of the Tempest class? I see no major compelling reasons to migrate. In fact, I think that many if not most DSP style calculations can easily be done on the Tempest class if you use the IQMath library, which is used to map floating point calculations onto fixed-point ones.

Also, when comparing the Blizzard class to competing offerings from other manufacturers, it doesn’t really impress me:

  • Freescale has been offering their Kinetis controller for a while. Running at 150 MHz (the K70 type) and equipped with many useful peripherals (among them, a LCD controller) this seems better equipped than the Blizzard class, and almost twice as fast.
  • NXP will soon be releasing the LPC4000 family, which will run at 180 MHz and which has a Cortex-M4 together with a Cortex-M0 on board. Again, in terms of raw performance, this one leaves the Blizzard class kicking in the dust.
  • ST recently released their STM32F4 series. This stunning Cortex-M4  microcontroller runs (from flash) at 168 MHz – more than double the speed of the Blizzard class. It has loads of memory, many peripherals, an external bus and so on. I seriously doubt TI’s Blizzard class will beat this one.
I hope TI will follow suit and release a Cortex-M4 offering with a performance similar to or better than the ones above. If not, I think they will not compete well in the Cortex-M4 class arena.