Memory: 16 KB Instruction Cache, 16 KB Data Scratchpad
I'm wondering if it's possible to combine that or dice it in some way? On top of that, the program resides in SPI flash (128 Mbit -> 16 meg).
EDIT: ok - the above makes no sense, so yes, on 16K on-board RAM (and the other is for cache).
Short of more info, I'd be willing to bet that some of that flash can be set aside (or used like) variable space (albeit at a slower speed), and the on-board memory is more for high-speed stuff (and you'd have to swap things in/out - though likely they'll have a library for all of that - maybe).
If all of that is true (or close to the truth) - well, I don't know if it would be better than the propeller or whatnot, but it certainly looks interesting...
It does seem like the flash can be used for data and program space - and it appears like it can be read/written to from the cpu - so it's kinda like the flash storage on the Arduino. I would imagine it can be used similar - although slower - as variable memory (given a proper lib); and "paged" into the faster on-board 16k RAM.
You're correct, you can access the 128MBit SPI Flash as any other read-only memory mapped memory -- you can execute out of it or load data (you can also write to it but need to use a seperate channel, it's not directly memory mapped to write).
You're also correct on the sizes of the ICache and Scratchpad. You can execute code which resides in the scratchpad, but can't store data in the I-Cache.
No. The only external addressing is through QSPI0, and that only has one chip select line hooked to it. They do make small amounts -- 512k -- of SPI RAM, but that on its own would make the chip boot process interesting.
You seem to be a more likely customer of their U500 platform, at over 1 GHz, 64 bit, cache-coherent multicore, DDR3/4 controller, USB 3.0, PCIe 3.0, and gigabit Ethernet. That one's also on a 28nm, process rather than 180nm. That should run Linux or an equivalent like the Raspberry Pi 3 or the Pine64 can. They don't seem to have an SBC ready for market with that chip yet.
This is their embedded / tinker / maker single-board computer based around their E300 platform with on-board SRAM. It's more like an Arduino or a Pi Zero.
RISC-V is appealing but if I'm stuck at 32KB or less of RAM I'd stick with the Parallax Propeller which has 8 parallel 100mhz cores.