Monthly Archives: August 2014

SR latches & flip-flop excitation tables

When studying for the exams of Digitale Elektronica II, I needed the excitation tables for a NAND SR latch. After constructing this myself, I wanted to verify on the internet if it was correct. On Wikipedia I’ve only found the excitation table for a NOR SR latch. When I’ve looked further, I found that many of the NAND SR excitation tables we’re mixed up with those of the NOR.

So I figured I would share the excitation tables here once and for all:

  • NOR SR latch
    Q(t) Q(t+1) S R
    0 0 0 x
    0 1 1 0
    1 0 0 1
    1 1 x 0
  • NAND SR latch
    Q(t) Q(t+1) S R
    0 0 1 x
    0 1 0 1
    1 0 1 0
    1 1 x 1

An “x” means “don’t care. You can easily make these yourself from the SR characteristic tables. As you can see, the values of SR are the complement for NOR and NAND (a 1 in the S or R column in the NAND table corresponds with a 0 in the same place in the NOR table and vice versa).

Start programs at boot in Windows 8 and 8.1

Recently I was searching for a way to start programs at boot. Unfortunately the task manager only displays the programs which already start at boot and does not provide an option to add programs to start at boot.

task-manager-startup-100049076-orig

The solution is to create a shortcut to the exe file (or ohter file that boots the program) and store this shortcut in the StartUp folder. The problem is how to find the StartUp folder.

According to Jasone’s blog, the StartUp folder is in the current location:

C:\Users\<username>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup

This location can easier be accessed by running the following command in the search box at the start screen (accessed by the Windows key) of in a terminal:

shell:startup

That’s all there is to it. Copy the shortcut there and the next time you boot, the program will start up with Windows.