That darn Intel jingle...

[Allison]

>
>Subject: Re: That darn Intel jingle...
>   From: "Chuck Guzis" <cclist at sydex.com>
>   Date: Thu, 03 Nov 2005 15:32:44 -0800
>     To: cctalk at classiccmp.org
>
>On 11/3/2005 at 6:22 PM ard at p850ug1.demon.co.uk 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.

Z80 PIO.

However the 8255 is of the 8080/8085/z80/ and general Intel lineup and 
due to that also the most widely multiply sourced.  It's ugly but what
comes in to do better?

>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.

D72055 the last version of the part hit 12mhz.  If your going on PCI 
why bother and just put a gate array to work.

>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?

Well there are plenty of 8251, 8253, 8259 around, then there are the 2681s
and (gag) 8250 series. 

Not many but then what do you need after lots of ram?


Allison