| ??? 05/08/09 15:50 Read: times |
#165156 - well, so let's state it in other way Responding to: ???'s previous message |
Erik Malund said:
AT89S52 gives noise problems.
I doubt it. I recall no instance where noise problems were related to a particular processor. Given a certain level of noise - due to various reasons, including decoupling etc. issues - the AT89C52 MAY be working while the AT89S52 MAY fail. I guess the newer 'S' is built on a chip with smaller transistors, read, less parasitics and faster gates. The older 'C' simply may reject higher frequency interference because of its clumsyness. I can imagine an mcu design, where certain supply voltage (and maybe also I/O) filtering is performed in-package; such an mcu might be slightly more expensive but can be more competitive on markets where EMI rejection matters. The manufacturer might even not admit this overtly, for various reasons. That relying on this property of a certain technology is a bad thing, and that migrating to other mcu family will probably not save the day, is another question. JW |
