| ??? 02/21/03 17:15 Read: times |
#39692 - RE: 8255 whats wrong Responding to: ???'s previous message |
1) The 82xx chips were made for the x86 bus and are thus, at best, a kluge when used with '51 processors.
2) The list of 82xx manufacturers is getting shorter and will soon be so short it is invisible. 3) The timing of the 82xx is based on a few MHz, making the use of them with a modern '51 derivative running at speed even harder. 4) A few latches or, even better, a small PLD, will do the job without you having to jump through timing hoops 5) So many modern solutions exist: IIC, SPI, CPLD, WSI, HC(T) you name it, even 40xx is faster. 6) While a Ford model T may have some nostalgic value, a new car rides better. 7) The fact that many professors and posters of schematics on the internet are too lazy to update their designs, does not make it "right". 8) When asked to look at a design that almost/not works, if there are 82xx chips involved, that is usually the source, be it hard or soft. Running out of time, this will do Erik |



