Tag: Cortex-M3

Is Architecture Becoming Irrelevant?

A few days back I was reading an article on EEtimes. It was an interview of Microchip CEO Steve Sanghi. One question, which particularly seemed interesting, was what if MIPS is acquired? These days MIPS is said to be looking for buyers and this may be thought to hit back the PIC32 as well. But Steve Sanghi’s response was very clear and blunt: “As we said before, core is not important”…..”More important [for us now] is the development of compatible tools, services, support and libraries”….. “Core is not that critical to solutions we offer. We see no changes in our strategy in [using] MIPS” (Source EETimes.com).

Well this was interesting as well as a fact which we may notice. For example, look at the MPLAB IDE, it support 8, 16, 32 bit offerings which are way different from each other. As an another example we can notice Atmel Studio 6 which supports AVR as well as ARM-Cortex-M3. Although microcontroller is unlike PC programming where we need to handle each register but if well documented libraries are there, the programmer seldom needs to consult the actual architecture. Also the differences even lie between different families of same architecture. As example see the StellarisWare or the TCP/IP stack from Microchip. They are great pieces of firmware, very well documented and programmer can work effectively by only learning the APIs which manage the underneath hardware registers. (continue reading…)


Why Invest in ARM Cortex-M3?

Often I have thoughts where to invest my “pocket money” and more importantly time and effort. The ARM architecture, I think, is the answer. Currently a kit of TI’s LM3S8962 Stellaris series (which was LuminaryMicro when I had bought this demo kit, ahh I can’t forget LuminaryMicro, recession has some unforgettable memories in my mind) rests in front of me and, as always, am “admiring its beauty”. So “why” is the question:

  • ARM is well penetrated and it will stay in market for a long time (at least a decade, I think).
  • The development tools are everywhere easily available and those are cheap. So you can get started easily.
  • Well supported architecture among IC vendors, in-fact, it has become a “fashion” to launch MCU based on Cortex-M3. Look at TI, NXP, ST, EnergyMicro etc. etc… They are “running” hard to catch it.
  • ARM is well heard among tech managers so it will increase an engineer’s market value. Somehow I realized that if I want to stay in this field (embedded systems), then I will need to maintain my market value. Otherwise somebody else is always there ready to replace me with lower pay.
  • All other advantage which something “in” may have.

So I have decided to “target” this dimension more intensely in the coming times.


Where to go from PIC32?

Many embedded geeks think that what will be their future if they invest time, effort and money in PIC32 family of microcontrollers from Microchip. Will their investment be secured, for instance, those choosing ARM Cortex-M3 based MCUs like those offered from TI, NXP, ST etc. The ARM users are confident that their experience will bring fruits when they will upgrade towards Cortex-R and Cortex-A series of relatively high end processors. One thing is also being observed that after these power MCUs, one often tends to go for MPUs (application processors) rather than staying at MCUs. While MIPS M4k/14k and are designed for general purpose embedded and deep embedded applications, especially for MCUs, up above them are mostly MPU rather than MCUs.

An interesting thing to note is that Microchip has licensed MIPS M14k and M14Kc core families for their future offerings so it seems obvious that they are committed to this architecture and will bring more powerful MCUs based on it.

Anyways, here are some the vendors which offer general purpose MPUs based on MIPS processor cores.

Ingenic Semiconductor’s MIPS32 based XBurst series: From JZ4750 to JZ4770 they are offering 360MHz to 1GHz clock speeds. These chips are very power efficient with power consumption down to 0.05 mW/MHz and with performance upto 2.5 DMIPS/MHz performances; amazing! JZ series has been successfully used in many tablets including Cruz tab. Ingenic has been a very successful story for MIPS. They are offering tools for WinCE, Linux and Android.

Toshiba TX39 and TX49 Series: TX39 is MIPS32 based while TX49 is MIPS64 based product. The clock speed ranges from 200MHz to 660MHz. The products are targeted towards digital entertainment and multimedia applications.

NetLogic’s Alchemy series: The processor family is targeted towards ultra low power embedded microprocessor applications. From Au1000 to Au1380, they provide varying degree of speed vs power performance. The good thing about alchemy series is that they offer built-in MCU-like peripheral set including GPIO, 10/100 Ethernet Controllers, USB Device and Host, UARTs, IrDA Controller (SIR, MIR and FIR), AC-97 Controller, I2S Controller, SSI Controllers and LCD Controller. This chiefly brings them closer to MCU features with MPU capabilities and tool sets.

 SiS’s Android-based SoCs: SiS681 integrates a 32 bit 576 MHz microprocessor with 32KB/16KB L1 I/D- cache size, 32 bit 1.3GHz DDRIII memory subsystem up to 512MB, 266MHz 2D graphic engine, x8 NAND Flash & SD/MMC interfaces, and 10/100 Ethernet Medium Access Controller.

SiS691 is featuring Open GL ES2.0/1.0 3D graphic engine, 3DStereoscopic display engine supporting 50/60Hz Pattern Retarder type of 3D LCD panels, VP6, WebM VP8 and Multi-View Coding (MVC) video format support as part of SiS Universal Video Decoder (UVD), dual channel DDR3-1333 memory controller, MIPS-based CPU as well as 400MHz audio DSP processor.

PMC-Sierra: The processor solutions are offered with Standalone processors pin-compatible and software upgradeable from250 MHz to 1 GHz, Low standby and operating power (as low as 100 mW and 1 W, respectively), Integrated processors up to 1 GHz with standard interfaces like PCI,GigE, DDR SDRAM, EJTAG, and built-in IPSEC security, Wide support from Third-Party Development Partners. PMC-Sierra’s market is networking devices.

There are, off-course, many other options but above are the most notable. There are obviously many way-outs after PIC32 but usually MCU geeks are unaware of those. I little research tells the story that there are many “brotherly” MPU vendors of them and the expertise gained after PIC32 MCU will surely bring fruits in the future. What needs to improve is, however, the MIPS marketing strategy. They need to “highlight” their architecture like ARM does; i.e., every chip that carries ARM core inside, ARM is boldly written on it. As far as the performance of cores is concerned, MIPS is not less, if not greater, than ARM rival.



The 32 bit Hobbyists

The 32 bit hobbyists? What does it mean. I mean to say the near future generation of hobbyists which will do minor tasks like blinking an LED or displaying some text on LCD on 32 bit microcontrollers. But why 32 bit when there are hell lot of 8 bit and 16 bit MCUs out there? Because 32 bitters will be so common and cheap that every “”micro-aware” guy will choose only these buddies. They are now very power efficient, come with many peripherals and easy to solder “hobbyist friendly” pin packages.

So what are the options?

Many vendors have “jumped into” the band wagon of 32. Everybody is there with there own “unique” offering. However, by features and capabilities they are almost the same.

Vendors like TI, NXP, ST, Atmel are providing solutions with ARM Cortex-M3 based MCUs with Atmel has another option of it AVR32 offering. AVR32 business has not been very successful till date. However the Cortex-M3/4 has just shaken up the MCU industry and it is seen everywhere. Especially, TI’s Stellaris (formly LuminaryMicro) is very impressive.

Microchip came up with a unique solution called PIC32 based on MIPS M4k. Well, MIPS is an old guy but completely unheard in MCU market. It’s great architecture, well penetrated in deep embedded and high end markets like data server, networking devices with established 32 bit AND 64 base. However, Microchip did several smart moves to “encash” its 8 an d16 bit “base” into 32 bit. They kept the same style of coding, same IDE, and same concept of hobbyist friendly MCU with packages down to DIP-28. 32 bitter in DIP-28, amazing! Here is a small comparison of PIC32 and Stellaris series.

However, there are some other vendors with a some difference. Yes, I am talking about Freescale’s ColdFire.

To summarize, there are many other vendors with great 32 bit offerings. Why buy an 8-bitter when almost in the same price, more powerful, easy to solder (as well) and well supported option is there.

So, welcome 32-bitters!


PIC32 vs Stellaris Series from TI

PIC32 and Stellaris series both lie between the high-end microprocessors and low-end 8/16 bit microcontrollers. Both architectures are designed to be best fitted into microcontroller and deep embedded applications. However, they are powered by the cores of very different vendors competing in architecture market.

PIC32 is the flagship product of Microchip Technology Inc. while Stellaris is now owned by industry leading Texas Instruments (TI). PIC32 is powered by very efficient M4K core from MIPS while Stellaris is powered Cortex-M3 from industry standard ARM architecture. Both the series have their advantages and disadvantages.

Architecture wise both the controllers are very similar with M4K a little more efficient with 1.5+ DMIPS while Cortex-M3 with 1.25 DMIPS performance. PIC32 can pull with ful 1.5 DMIPS performance while Stellaris is a bit lagging.

PIC32 has a great base of 8/16 bit PIC developers. No doubt PIC is the king of 8 bit market. Microchip offers the same MPLAB IDE for all 8, 16 and 32 MCUs. Stellaris, although, does not have such base, but ARM is most widely used 32 MCU. So Stellaris has the advantage of a huge number of “brotherly” MCU vendors like NXP, Atmel and ST etc.

The peripheral sets are also very much the same with emphasis on communication peripherals like CAN, Ethernet, I2C, USART, etc. So one can do pretty much everything he wants to do. Both MCU series have lots of memory around upto 512KB with Stellaris an advantage of using external program memory as well. PIC32 lags in this point that external “program” memory can not be interfaced with it.

Stellaris have a great upward market. With the helm of devices with Cortex-A5/A8/A9 which provide best properties of application processors. This area is somewhat weak for PIC32. With Microchip, you end up with MCUs only and getting upwards means changing vendor, tools and everything. Though working on application processor is really different from that on MCUs, from Microchip one really needs to look around where to go? (Here I tried to answer this question). There are some very popular and successful stories like Ingenic from China or Alchemy series from NetLogic, but they are not great in number. One thing different about MIPS is that they are well penetrated in the market but only in deep embedded applications. It is difficult to find them into general purpose MCU market as one can find ARM. Often MIPS licensees ignore to mention the great power of MIPS behind their products’ “tag” which, I think, is bad marketing effort from MIPS team. But they are there and there is no doubt about that. So the best available option is to move to extremely power efficient and feature enriched media processors from Ingenic.

Anyways for an MCU user PIC32 and Stellaris offer almost the same. Both are solder friendly and hence hobbyist friendly. But they deserve a good presence in professional markets as well.

For 8/16 bit PIC users, PIC32 is a great step forward. For 8051/alike lovers, Stellaris is good, though it’s not a bad idea to taste both of them and decide yourself what suits your requirement and which is more in-lined with your previous experience.


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