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Comment by dkersten | Hacker News Reader

How do the low-end ARM devices compare to 16bit and 32bit AVR and PIC offerings?

Recently, I have been doing a lot of development for both the (8bit) AT90USB162 and the (16bit) PIC24HJ. The PIC24HJ range of 16bit PIC microcontrollers packs an awesome punch at 40 MIPS, has mostly 1-cycle instructions and two hardware SPI peripherals (which, for me, is important. On the other hand, the AT90USB162 only has one). I have been interested in ARM, though, so am wondering if it would be worth switching before I become to reliant on other microcontrollers.

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There is no 16bit AVR.

Cortex-M3 runs circles around any 8-bit parts in most settings - single cycle instructions, hardware multiply and divide, 32bit registers, good interrupt processing support. There are even power efficient parts (Energy Micro EFM32, STM32L, etc). The other nice part about CM3 is the family support: Its one compiler toolchain and one debugger toolchain. With CMSIS (a software library standard) its "easy" (if you don't use a specific peripheral in a specific way) to move code across vendors as well.

PIC24 is a good half step, but the proprietary toolchains are a major turn off. PIC32 is at least a MIPS core (with some vague gesturing on Microchip's part for their GCC port - good luck actually building their horrible code dump though), but doesn't appear to be energy-use competitive with CM3 or CM0.

Do you have a recommendation for a specific CM based microcontroller? Preferably one that is well stocked on mouser and has USB support.

Also, any tips on getting started? How do I program them? Ideally, I'd get an in circuit programmer, rather than a development/demo board.

The LPC1768 is quite popular and you should never have problems with stock. I got started with a $30 development board from NGX (google "1768 blueboard") paired with a $30 USB jtag programmer from the same store. The older LPC2148 was also quite popular for hobbyists, but it's ARM7 not CM3.

Since I was more interested in learning the micro then screwing around with toolchains, I just spent the money and got a personal license for Rowley Crossworks ($150). It took me under an hour to go from software installation to flashing an LED, so I'm pretty happy with that decision.

I've never done any development for the non-8-bit Atmel/Microchip products, so I can't really compare. The NXP Cortex-M3 I'm currently using for a project has one SPI and two SSP peripherals.

My impression from talking to other engineers is that there isn't a lot of investment in those architectures (financial or emotional...) and most people think that economies of scale will make ARM dominant in the long term. From a business perspective, neither company seems to believe they can afford to be without an ARM product line.

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