That darn Intel jingle...

Chuck Guzis cclist at
Thu Nov 3 17:32:44 CST 2005

On 11/3/2005 at 6:22 PM ard at wrote:

>The worst, by far, has to tbe the 8255 parallel chip. That was clearly 
>designed by soembody who didn't think what he was doing. For those of you 
>who've not read the data sheets, any write to the mode control register 
>clears all output port lines to 0.

For what it is and WHEN it was developed, the 8255 is a pretty good device.
 There are still new products made that use it (very popular in the data
acquisition area).  I can't think of any other single parallel interface
chip from the 70's that's still puffing along.

I wish the thing was faster.  The NEC 82C55AC variant is good to 10 Mhz,
but that's pretty slow when you're talking about a PCI bus.

There are precious few of the really good peripheral chips from the early
days of the microprocessor that are still as useful.  The Signetics 2651
USART, maybe?


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