The $6 805x-type to which I refer is the DS 89C450, which has 64KB of Flash, only 1 KB of XRAM on board, but which can, indeed, move a block of 4090 bytes of data from point A to point B at 60 ns per byte, using one of its two data pointers in autoincrement mode and, in fact, with the addition of just one small CPLD, it can move it twice as fast (with just a teensy bit of overhead for a subroutine call and return) over a range up to 16 Mbytes. I don't use that, but ... That 128 macrocell CPLD only added $2.40 (I bought ~100 of 'em on eBay since 5-volt CPLD's are becoming scarce) to the system cost and provides several other interesting functions. That CPLD also allowed me to add 1 MB of SRAM to the system, which was more than I needed, but ...

I looked at an ARM for just this application, though I went with the DS89C450 because it was "interesting." Now DigiKey wants a lot of money for this chip, but they're "out there" at reasonable prices. Erik has pointed out that he buys his SiLabs 'F120's at somewhere in the $6 range, too, and thos have a lot of additional features and have 128KB of code space along with 8 KB of on-chip XRAM. Both of these chips have extensive features to support the use of external devices if you need them, RAM being among 'em and even the ultra-fast 'F120 can have its external bus cycle stretched via an SFR to such extent that it can, if necessary, talk to an i8255, ... imagine that!

RE