| The main thing that is usually overlooked is that Raspberry Pi is a charity and they do not make commercial products with the intent to make money from it. Well okay, why would you make the choice to go with something like the STM32F4 ARM Cortext-M processor vs something like the Raspberry PI with an ARM Cortex-A series processor? Well I'm glad you asked. First you need to ask, what does your device need? Some things to consider:
- Power consumption
- Real time sensors or I/O
- Safety critical
- Processing / Computing power
- Image / Video processing
- < 10" display
- > 10" display
- etc All of these are at the beginning of making a choice of which processor series you want to use. But, wait if an Cortex-A Series can be sold for $5 why don't I just got with an Cortex-A series, because, well they aren't. See my first sentence and now my following. If you compare the higher-end M4/M7 processors from ST (STM32F4xx / STM32F7xx with Chrom-ART / DMA2D Support) vs something like the NXP/Freescale A9 single core (i.MX6Solo) at quantity 1,000, you're looking at between $7-$10 for the Cortex-M4 and $13-$15 for a Cortext-A9. ( http://www.digikey.com/product-search/en/integrated-circuits... ) ( http://www.nxp.com/products/microcontrollers-and-processors/... ) Okay, so they aren't that much different in price (depending on who you are and how much the rest of your system costs). So, you need to then compare it even further. Typically on a Cortex-M Series you are looking at an RTOS, whereas on a Cortex-A series you are looking at a real OS (Linux, Android, Windows, etc). Why does this matter? This has to do with hardware support and the core difference between an RTOS and an OS. If your board processor, peripherals, etc are not well supported or you are doing a custom pcb design, you are going to be writing your own drivers which equates to NRE (Non-recurring Engineering), which can be expensive. This cost could be consumed by the company as a business expense or be captured back into the cost of the device. Then you have tool chains, support, and familiarity, and so on. So, if the above did it's job, that might have helped into understanding why you may or may not go with a Cortex-M or Cortex-A series. And yes you may be right on the edge of going with one or the other. |