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<DIV>Ludis,</DIV>
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<DIV>I was sooooooooo not clear, about what i meant. what i meant is that I thought that the U17 chip was some kind of a watch dog & that I assumed that one of the RC networks to the left of the print were the RC networks that bring up the chip & that i could tie into the input to the chip & have the chip control the output. I saw the Resister on the ~ RESET line but thought that it was just a pull up for the line for some reason. From the way that this chip is behaving it appears that this is some kind of power control chip (kind of like a on off relay). I am also guessing that one of the RC networks on the left side (.2, .3, .5, .6, .7, .9, .10) control the timing of the chip coming up. for example one of the RC networks brings VCC1 up. another brings VCC2 up & another brings up VCC3. during this time it holds the ~RESET line & after all the power comes up it lets go of the ~RESE!
T line. </DIV>
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<DIV>the question in my mind was which RC network controlled the ~RESET line & that is what i guessed was .2. maybe i am reading in too much here but if this is not kind of how this chip works then what are all the RC networks for? (more rhetorical than anything i suppose). </DIV>
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<DIV>I guess i ought to just tie to the ~RESET line & get on with life????????</DIV>
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<DIV>tanks again, sorry for the confusion. </DIV>
<DIV>BW </DIV>
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<BLOCKQUOTE style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style="FONT: 10pt Arial">----- Original Message ----- </DIV>
<DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B> <A href="mailto:ludis@cruzers.com" title=ludis@cruzers.com>Ludis Langens</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To: </B><A href="mailto:ludis@cruzers.com" title=ludis@cruzers.com>gmecm@diy-efi.org</A></DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> 3/11/01 11:53:02 PM </DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Limp home mode</DIV>
<DIV><BR></DIV><FONT size=2>
<P>
<DIV>Bob Wooten wrote:</DIV>
<DIV>> </DIV>
<DIV>> what I am</DIV>
<DIV>> ultimately trying to do is to pull the ~RESET line so that I can shut down</DIV>
<DIV>> the CPU. with the emulator that I just bought. I figured that I could tie</DIV>
<DIV>> into Pin 2 but it appears that this is not working as I guessed it would by</DIV>
<DIV>> holding it down it appears that the entire CPU is still "dead" & the</DIV>
<DIV>> emulator does not like that.</DIV>
<DIV> </DIV>
<DIV>Pin _two_? There's no chip in a '7730 where pin 2 is ~RESET. The</DIV>
<DIV>regular reset comes from pin 1 of U17. You may notice a 5.1K pull up to</DIV>
<DIV>VCC. I'm quite sure that everything driving the reset line has an open</DIV>
<DIV>collector driver. That means that at most, you have to sink about 1ma.</DIV>
<DIV> </DIV>
<DIV>-- </DIV>
<DIV>Ludis Langens ludis (at) cruzers (dot) com</DIV>
<DIV>Mac, Fiero, & engine controller goodies: <A href="http://www.cruzers.com/~ludis/">http://www.cruzers.com/~ludis/</A></DIV>
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<P></P></FONT>
<P></P></BLOCKQUOTE>
<DIV> </DIV>
<DIV>--- Bob Wooten</DIV>
<DIV>--- <A href="mailto:r71chevy@earthlink.net">r71chevy@earthlink.net</A></DIV>
<DIV>--- <A href="http://www.r71camaro.homestead.com">www.r71camaro.homestead.com</A></DIV>
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