??? 07/25/05 12:50 Modified: 07/25/05 13:18 Read: times |
#97991 - no can do Responding to: ???'s previous message |
I want to interface 8052 with 22MHz crystall with 8255
no can do. You see, in the olden days when the king of diamonds were still a jack, the '51 ran with an 8 MHz clock or, if you were real adventurous maybe even 12 MHz. In addition these kinder gentler derivatives consumed 12 clocks per operation. Thus any schematic including the 8255 dates from the antiquity. In those days a fairy godmother made a nice, kind, gentle, thing called the Goldilocks 8255 which really loved to be fed with a gentle clock of 8 MHz. Now you take one of the newfangled 22 MHz speed demons and it just spy fire and eat Goldilocks. Oh, well, there is no way the antique can keep up with a 22 MHz clock If you absolutotally have to use the antique, you need to lower your clock rate Erik PS: had you taken the time to "read" the datasheet, the above would have been clear to you. I used the word "read", please do not delete for being offensive. |
Topic | Author | Date |
8255 interfacing problem | 01/01/70 00:00 | |
well.. | 01/01/70 00:00 | |
8255 interface problem | 01/01/70 00:00 | |
If you must use 8255 | 01/01/70 00:00 | |
My datasheet says..... | 01/01/70 00:00 | |
Settle Erik! | 01/01/70 00:00 | |
8255 problem | 01/01/70 00:00 | |
hardware | 01/01/70 00:00 | |
adding to Steve.. | 01/01/70 00:00 | |
Comment | 01/01/70 00:00 | |
Relic | 01/01/70 00:00 | |
that was not 8255 | 01/01/70 00:00 | |
Actually.... | 01/01/70 00:00 | |
ot: 825x in PC | 01/01/70 00:00 | |
Parallel port | 01/01/70 00:00 | |
NOoooooooooooooooooooo | 01/01/70 00:00 | |
Ooops | 01/01/70 00:00 | |
OK I give it up! :-) | 01/01/70 00:00 | |
Just like | 01/01/70 00:00 | |
8255 in original PC | 01/01/70 00:00 | |
If I did not keep up with the times and | 01/01/70 00:00 | |
Do your kids drive Segway? | 01/01/70 00:00 | |
the real problem is not that the 82xx is | 01/01/70 00:00 | |
Erik - A history lesson | 01/01/70 00:00 | |
ok, even further back | 01/01/70 00:00 | |
Picky, picky | 01/01/70 00:00 | |
are we getting there now? | 01/01/70 00:00 | |
Oh altight then :-)![]() | 01/01/70 00:00 | |
More info needed | 01/01/70 00:00 | |
Pull up resistors. | 01/01/70 00:00 | |
Pullups | 01/01/70 00:00 | |
no can do | 01/01/70 00:00 | |
Yes he can! | 01/01/70 00:00 | |
does not make it current | 01/01/70 00:00 | |
my opinion... | 01/01/70 00:00 | |
did you not read | 01/01/70 00:00 | |
Nope | 01/01/70 00:00 | |
8255 PROBLEM | 01/01/70 00:00 | |
10 Points | 01/01/70 00:00 |