I'm trying to figure out with the most minimal part count how to convert an input of a digital IC to an edge-triggered input.  I am using the 82C55 IC and the input on it I want to make negative edge-triggered is the WR input. This is because I want to control both WR and the clock of an external latch (74HC574) with only one GPIO pin of a microcontroller.  I am able to pull this off by using a multivibrator (CD4538) and connecting the output of it to WR but the thing with that is I have to add a capacitor and resistor to create my own timing.  Is there a simpler way to convert a level-based input (where an output happens based on what level the input is at) to an edge-triggered input without introducing unnecessary long timings (which could happen with my multivibrator approach) and without using too many extra parts?
I am designing a hobby project that will run on a battery so I am trying to reduce power consumption. The SoC I am using has the ability to go into a deep sleep mode where it consumes very little power, and then can be interrupted by a falling edge on a pin.  I want to generate a high-low-high pulse when the state of a reed switch changes in either direction. I have been reading a lot and it seems that a one-shot monostable circuit can be built from a couple of transistors and an RC circuit to generate an output pulse when an edge is detected. I understand how that works. However, I can't figure out the best way to also pulse on the opposite edge.  One thought, was to just combine two one-shots that are configured to trigger on rising and falling edges respectively, and use the transistors at the output to pull the common pull-up low (kind of like a NOR gate).  Since I am a hobbyist, I am mostly using passive components. What is the "real" way of doing this in a low-power configuration using logic devices?  Edit: I figure I should mention something about the timing requirements. Normally the reed switch will be either open or closed for many seconds at minimum before changing states.  Edit: Here is an example of the circuit I was using for detecting only the falling edge:    And here is the ~20ms pulse it was producing for ~200ms button press simulating the reed switch (Channel 1 is Vbe for T1 and Channel 2 is measured at RST):
Create a virtual file that is actually a command I want to change the Message-ID header or better yet, discard it. I know everyone is going to ask "Why would you want to do that?" because I know it sounds weird to even write it.  Well I am developing a system that saves an incoming e-mail in EML format, changes it and sends it to the user, at some point the user can request to have the original EML sent to him/her. The issue is that when I re-send the EML it has the same Message-ID header which causes exchange servers to drop the re-send.  Of course I am hoping there is some option through postfix to do this, otherwise I will need to parse and change the EML but I rather not do that.  I tried to do this with "header_checks" and it works BUT I need to be able to do this conditionally, meaning only on a specific occasion, which I can identify by looking at the other headers, I want to remove the Message-ID. I listened to this on audiobook and it was great.  The premise was a human ends up travelling to an alien planet. The aliens have a perimeter to their 'base' that is under constant attack from the planet's animals. It is revealed towards the end that there is some sort of signal being transmitted that is making all the animals and plant life attack a certain point on the planet (where the aliens are).   Other major plot points I remember: The human traveller falls in love with an alien. The aliens have a sort of virtual training environment that simulates life outside the perimeter, where plants attack you etc. There is a secondary alien group that the human ends up with, and although they are rivals to other group, they have a trade set up.   Any help much appreciated! Thanks. What is the difference between a function decorated with  and one decorated with ? Let $T : V \rightarrow V$ be a linear operator. If $T^n = O_V$ for some $n \ge 1$, prove that $I_V + T$ is an isomorphism. I think I'm supposed to prove that both $T$ and $I_V$ are isomorphic, but I'm not sure and even if that's the right way to go, how am I supposed to prove that $I_V$ is isomorphic. Or am I going about this all wrong. Please help. Converting a string to a tuple in python Negative y value in polar plot I'm having some trouble with polar plots. I have to plot negative values, but without changing direction. I tried to set the ymin value to be negative, but it doesn't work.  \documentclass[10pt,border=10pt]{standalone} \usepackage{pgfplots} \usepgfplotslibrary{polar}  \begin{document} \begin{tikzpicture} \begin{polaraxis}[    xticklabel=$\pgfmathprintnumber{\tick}^\circ$,    ymin=-10,    xtick={0,30,...,330}] \addplot table{    0  -1     30 -2    45 -3    60 -4    75 -5    }; \end{polaraxis} \end{tikzpicture} \end{document}   Any suggestion?  For clarity, this is what I expected. How to prove $ \prod_{d|n} d= n^{\frac{\tau (n)}{2}}$ how to prove:   $$ \prod_{d|n} d= n^{\frac{\tau (n)}{2}}$$   $\prod_{d|n} d$ is product of all of distinct positive divisor of $n$,  $\tau (n)$ is number (count)of all of positive divisor of $n$ Word for an event that will likely never happen again I've read , but none of them are what I am looking for. I once read a book that used a word to describe an event that has happened in the past, but the odds were so astronomical that it will likely never happen a second time. The context I read these words in were the creation of the first life on earth (without any theological ideas). Basically, the text said that the scenario for the creation of the first living organism happened on a planet where conditions were just right by complete chance, and that the odds of this were so astronomical that it would likely never happen again anywhere in the universe over any length of time.  Sample sentence: "The creation of the first organisms was incredibly unlikely, the event can be called a _________ event, or an event that will likely never happen again."   I can't pretend to understand the validity of the claims by the text, but the words they used to describe these events were quite clever (and scientific sounding) that it would make a fun hyperbole.  I thought it was something along the lines of singularity event, but that doesn't sound quite right. Is it possible to check who is entering your website in PHP. I have a web application ( written in PHP) that should only allow users entering from some particular websites. Is it possible to get the referral websites by examining the _Request object? If yes, how? I found this odd relationship, $x^2 = \sum_\limits{k = 0}^{x-1} (2k + 1)$. Check if convergent in the end points of the convergence interval I have to find the radius of convergence for $\displaystyle\sum_{n=0}^{\infty}\frac{n}{n+1}x^n$, for x$\in$R. I think it is $r^{-1}=\lim_{n\to\infty}\frac{a_{n+1}}{a_n}=\lim_{n\to\infty}\frac{ \frac{n+1}{n+2} }{ \frac{n}{n+1}}=1$ so r=1. Then I have to find out if $\displaystyle\sum_{n=0}^{\infty}\frac{n}{n+1}x^n$ is convergent in  the end points of the convergence interval. I think I have to check for $|r|$. But we can't use ratio test (L=1) or integral test(not decreasing) for $\displaystyle\sum_{n=0}^{\infty}\frac{n}{n+1}$. How can I then check if it's convergent in the end points of the convergence interval? I just dropped my Vaporeon off at the gym, but to my surprise, he can still be viewed in my Pokémon list! The buttons are there to level him up, but I'm not gonna be able to get any Eevee candy for a few hours to try. Can I level him up while he's in the gym? Second-order non-linear ODE $2tx'-x=lnx'$  I differentiated both sides with respect to x:  $x'+2tx''=\frac {x''}{x'}$  Substituting $p=x'$,  $p+2tp'=\frac{p'}{p}$  But I have no clue what can I do from here on.  EDIT: $t$ is the non-dependent variable. QR Codes generation from MySQL rows Firstly, I apologise that this question is specific to two polynomials. I understand that this post will not help a lot of people, and for that I am sorry. I will make it up to you all by anwsering lots more questions in the future! However, as my lecturers enjoy time off on the weekend, I am unable to ask this to anyone else who would know what the heck I'm talking about. Sorry if my notation is not widely used, I can elaborate more if required. Please excuse my poor Latex too.  Let:  $B = Y^2 - X^3 + X$, and   $F = (X^2 + Y^2)^3 - 4X^2Y^2$.  I wish to find the intersection number of $B$ and $F$ at $P = (0,0)$  i.e $I(P,F \cap B). $  However, I want to use the following proposition to do this:  If $P$ is simple on $B$ then $I(P,F \cap B) = ord_P^B(F) $.  I will omit proving that $P$ is simple on $B$ as I hope it is clear to see it is.  I know that $I(P,F \cap B) &gt; M_p(F) * M_p(B) = 1 * 4 $, where $M_P(G)$ is the multiplicity of $P$ on $G$.  Now, consider the Image of $X$ and $Y$:  $K[X,Y] \longrightarrow \frac{K[X,Y]}{Y^2 - X^3 + X} \longrightarrow O_P(Y^2 - X^3 + X)$  $X \longrightarrow x$  $Y \longrightarrow y$  Where lower case denotes the image.  Then $ord_P^{Y^2 - X^3 + X}((X^2 + Y^2)^3 - 4X^2Y^2)$  Can be found by substituting $y^2 = x^3 - x$ into $(x^2 + y^2)^3 - 4x^2y^2$  Which gives:  $ord_P^{Y^2 - X^3 + X}(x^9+3x^8 -5x^6 -4x^5 +3x^4 +3x^3)=3$  i.e $I(P,F \cap B) = 3$, a contradiction to  $I(P,F \cap B) &gt; 4$ as above.  The correct answer I know is 6, so where have I gone wrong? I have some data which looks like:  sampleA    ATGC    10   100 sampleA    ATGC    120  230 sampleA    ATGC    200  110   I want to print the min and max using the values in both column 3 and 4. So my output should look like:  sampleA   10  230   Thanks in advance I have latitude and longitude as 19.0649070739746 and 73.1308670043945 respectively.   In this case both coordinates are 13 decimal places long, but sometimes I also get coordinates which are 6 decimal places long.   Do fewer decimal points affect accuracy, and what does every digit after the decimal place signify? How do I write this matrix as a product of elementary row matrices. \begin{pmatrix}3&amp;-1&amp;3\\ -2&amp;3&amp;2\\ 1&amp;-3&amp;1\end{pmatrix}  Any help would be greatly appreciated!  I have done this before with other matrices, yet this one is bringing me trouble. I have spent too long on this as I believe it should be easy and yet my answers are always wrong. What Do you do after you get the identity matrix?  What I am doing: So I first row reduce it to the identity matrix:   I first switch $R_1$ and $R_3$ Then $R_3-3R_1$ then $R_2+2R_1$ then $-1/3R_2$ then $R_3-8R_2$ then $R_2-2R_1$ then $3/32R_3$ then $R_1+3R_3$ and finally $R_2+4/3R_3$   I know there is many possible ways to get this too the identity matrix but this worked for me. I then apply all of the above steps to identity matrices and multiply them together to check my work but it never works out to be the original matrix so I am forced to believe something is wrong. java swing background image