| ??? 01/30/07 20:10 Read: times |
#131741 - Yes, the learner's progress Responding to: ???'s previous message |
Erik Malund said:
Richard Erlacher said:
There are a few, and I'd emphasize FEW, places where it's optimal, in the context of 805x applications, mainly because of its density, and those would be cases such as the one I mentioned before, where one has to have many dozens of outputs and inputs, all working within the confines of a single task, and all processed as a group, but with relatively precise timing (remember those control valves in the nuclear reactor?). If you have, say, 64 remote valves you have to open or close, and two local indicators for each, it's pretty easy to see how you might benefit from using 8 82C55's to do that. not really, the PCA9698 gives you 40 I/O on a similar footprint and does not 'eat' your port pins. What do you mean by "similar footprint?" Similar to what? Richard Erlacher said:
My only purpose in beating on Erik every time he says that using an 82C55 is wrong, categorically, is to remind him that, in this regard, HE is wrong. welcome to the club, your 'categorical' insistence that if the slow I/O is fast enough for the actual I/O it does not affect anything else is DEAD WRONG. Well, you're welcome to illustrate with a precise example, but you've demonstrated your inability to do that up to now. that Erik's position ... interferes with progress in many learners' instances every time he asserts it. stating do not use antiques is interfering with progress? Yes ... it interfere's with HIS progress. As for the 8255 being old, well, yes, it's old. So am I. But nobody seems to object to the use of the 1N914A diode. They've been around much longer than the 8255.
show me the improved method replacing the 1N914 (btw why use the 'A', since the original served the perpose) and I shall switch to the better method as I have done re the 8255. Erik For him, progress is simply getting through the course, or in other cases, getting his hobby project to work. If he "stamps his feet" and, in general, has a two-year-old-style tantrum, as you've repeatedly recommended, he'll be tossed out of the class and have to pay for it again and take it next term from another instructor. That's not very cost-effective. If it works, meeting all the requirements, it works. There's no way to make it "work" better. If it's cheaper, well, there's room for discussion. Exceeding requirements does not improve anything. If safety margin is a requirement, then, yes, of course, you have to meet that, but exceeding that without justification will, justifiably, get you fired. RE |
