Got a Logitech Performance MX on “special” at Best Buy this weekend (80$ for a mouse… what a slaughter) because I just have a laptop mouse and am tired of not having anything to rest my palm on. At first, it’s great. Looks like a race car, good performance, nice receiver, rechargeable on the fly etc. Then, something feels off… something uncomfortable. I turn the mouse over and the fatal flaw. The sensor isn’t placed at the center of the mouse but almost under your thumb…

Then I reconfirmed my discomfort. Since the box says that it’s the best mouse the “mice experts” came up with after making a billion mice, I figured I must be able to use it at the zenith of comfort. I closed my eyes and made the most natural horizontal draw (ie, rotate around a point on the wrist which is placed on the table such that the instantaneous motion of the mouse is the tangent of the arc I’m drawing). I look and the cursor is moving diagonally on the screen.

In order to produce the intended horizontal move, I had to either lift and move my wrist (very uncomfortable) or continuously extend and retract my wrist (very uncomfortable as well). You can also resolve this if you hold the mouse differently. If instead of putting the thumb into the intended groove, you rotate the mouse to compensate for the vertical move, you can also draw horizontal lines at the cost of having a gap under your palm.

Overall, it’s a sexy sleek black mouse but not necessarily ergonomically superior to the 2$ mouse you can get at any random stores. In other words, if you want to pay 100$ for it, you’d have to be willing to buy the different look, not rationalise it with ergonomics.

Heed the warning and it will save you days in debugging with random error appearances that simply won’t go away with any numbers of repairs and recompilations because you’re simply not recompiling your circuitry!

On designing FPGAs or CPLDs on Altera with their primary software designer, the Quartus, a compilation of a multi-level circuit will result in the compilation of only the topmost level. In order a change in say the bottom level, you would have to compile the bottom level, create new module symbol, go to the next level, update the symbol, compile that level, create module symbol and move one level up until the top which obviously makes it extremely ridiculous to debug.

Here’s some sample code for VHDL that does the same thing as block diagrams:

Suppose you have pre-made level2 that you wish to put together

architecture structure of toplevel is
    component level2
        port (a,b: in bit;
        c: out bit);
    end component;
begin
    c1: level2
        port map (in11,in12,out1);
    c2: level2
        port map (int21,in22,out2);
end structure;