Hi algilsan,
You wrote:
Recently i have nottice that Cygnal is producing fast 8051 uC's up to 100MIPS !!, so anybody knows if this is really trully?.
Don't be too excited with the power of microcontroller shown in MIPS. It's at least 10% advertising and brand name.
All what I'm going to tell you bellow are only concerned to this power.
I'll not talk about how big is the memory, internal RAM, what kind of features and peripheral has been implemented on Dallas and Cygnal products, which among these features emphasizes one or another micro.
And last but not the least the price of micro.
As far as I know (up to 26 april 2003), the Cygnal didn't succeed yet to cross beyond 50MIPS.
Maybe in the lab, but not enough for mass release.
Thus, the 100MIPS it's only a target.
If you dig a little inside data sheet you can easily notice that access time of FLASH memory is 40ns and the minimum instruction time is 10ns (for 100MIPS) and 20ns (for 100MIPS).
In order to solve the difference, it was implemented a branch target cache and prefetch engine fitted between the FLASH program memory and the 51 core.
Even if the designers provides options to exclude caching of certain types of data, as well as the ability to pre-load and lock time-critical branch locations to optimize execution speed, things are far from perfect.
I mean the 50MIPS are not quite 50. Read the data sheet and especialy about cache miss penalty threshold and you'll figure out what I mean. However, it worths the designers effort and should be greeted with applause.
If they didn't overcame the problems that comes up when core is running at 100MIPS, i have no doubt, will succeed soon.
The cygnal products are great. Besides that, they provides and cheap development boards.
In Maxim / Dallas garden, thing don't look the same. If they plans the 89C420 running at 50MIPS, now they give up and stated clearly 33MIPS. And I have serious doubt that will be ever increased to 50.
However we don't have to forget that 89C420 is working at +5v and cygnal at 2,7 - 3,6V.
What's your overkill application that needs such resources (> 50 MIPS, DMA .....) ?
Silvio