Nate, You are so right about using a MPU for basic functions like replacing a 555.
If one learns the basics of a MPU in what would be a 555 application, this same technology can be applied to many other applications...just change the software and maybe add a I/O buffer. In one MPU one can make many 555 circuits if needed. Also consider having switches controlling inputs to select a number of timing arrangements including pulse width and on/off timin, etc. Once one learns a MPU application rebuilding the same circuit to do something else is so easy...pecking on a keyboard writing software. In a 555 one has to practically redue the circuit. This is one reason software has so influenced technology...it is easy and powerful. A software driven circuit can be made to make decisions based on inputs, timers, etc. I still use some hardware for some functions. MPUs and computers fail, and often fail because they get glitched and blown out of the program. Still all the components are fine, just not working. Often a hardware approach like the 555 does not have this problem. Failure recovery of a computer is another issue that requires lots of thinking. 73, ron, n9ee/r >From: Nate Duehr <[EMAIL PROTECTED]> >Date: 2008/04/24 Thu AM 03:44:53 CDT >To: [email protected] >Subject: Re: [Repeater-Builder] Re: Carrier Control Timer (use the COR-2 >circuit) > > >On Apr 22, 2008, at 12:25 PM, skipp025 wrote: > >> >> The 555 is one of the most useful electronic circuit chips ever >> made. It has a fairly large number of possible simply configured >> mono & astable (cycle) circuit operations. And it's just as easy >> to get lost when trying to use it for specific tasks. > >Additionally along the "do-it-yourself" lines... > >Taking a small amount of additional time to learn how to program a >microcontroller like a Microchip PIC or an Atmel AVR, and you no >longer have any of the limitations of a 555. (Of which there aren't >many, but... still.) > >Virtually every piece of consumer electronics moved to these highly >useful little chips 10 years ago. They're also everywhere in your car >(in specialized "hardened" varieties... automotive electrical systems >are hard on "computer" hardware), etc. > >Learning them will lead to other more advanced projects later on. And >implementing a timer in one, is barely a "medium-beginner" stage. > >Most manufacturers provide sample code to "blink an LED" and if you >can figure that timing loop out, modify it and play with it a little >bit, you're about 30 minutes to an hour away (as a new beginner) from >a working timer circuit that will do whatever timing you want... you >type in the instructions, and the chip does it. > >You apply some very basic electronics to that to perhaps drive a >transistor as a "switch" so you can sink or source more current than >the microcontroller can handle a LOT of current anyway) and learn the >joy of bypass capacitors to keep RF in/out of your circuit (since >you're using the thing around radios!), and you're done. > >Don't like the timing? Plug your $39 programmer back into the circuit >and put a different timing value in the software running in the chip. > >I wouldn't say it's always more flexible than something like the 555, >because a guru can make a 555 do things it never should have. But >it's a lot easier to get your head around if you have any kind of >computer background, especially a little computer programming >experience! > >Not to mention, fun! > >-- >Nate Duehr, WY0X >[EMAIL PROTECTED] > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
