I have been looking at current mainstream 32bit embedded processors for my project (ARM, cortex, PPC, coldfire, etc). I would sure like to find a single device that has most of what I need, but I am running out of places to look. The main problem is memory support.
The wish list is: cortex M3
40-60MIPS performance simple 3 banks of Flash 1MB internal, 512KB, 256KB 2 banks of RAM 1MB, 512KB 4+uarts wdt rtc lcd support A/D D/AI don't expect to find one device that has all that built in, but I'd expect when you start with a core that has 4GB address space there would be at least a few devices supporting a good chunk of that. Instead there are lots of devices with no more than 512K internal code Flash, and 64K internal SRAM. If they have more it is broken up into small non-contiguous pieces. An example is the STR912. Most of the bells and whistles I want, high speed internal flash and sram, but just not enough of it.
External memory support is either limited, not mapped contiguous with internal memory, or some hokey bank switched scheme. Give me a few more address lines or programmable ext. chip selects.
At the other extreme are devices with much higher clock speeds, almost no internal memory but huge external memory support. These are typically large BGA packages and one look at the data sheet tells you that the design is going to take a lot longer and have an extra 2-4 layers.
Isn't there anything between these extremes?