Speed of Dark Blog

So this is a more than useful web page. For anyone out there playing with a quadrature encoder.

http://letsmakerobots.com/node/24031

I finally decided to update my MPLAB IDE to the newest version, X, and decided to try installing it on my linux machine (Fedora 14 on a Dell Inspiron 9100, 2GB RAM 2.8 GHz Prescott P4, 256MB Radeon 9800).   I was confronted by a *.run file.  Being a Linux user and not a Linux guru, I stumbled about a bit trying to get it to run.  (Ironic, yes?)

Here are the steps:

• Download the almighty *.run file from Microchip
• start up a terminal
• become superuser
• go to the directory of the downloaded file
• chmod +x <filename>
• ./<filename>

Done.  One very important note, something I had forgotten a couple years back but was reminded of by way of iron fist: The “./” is not optional.  Ever.  Linux is incapable of making simple assumptions that one familiar with DOS (or even CP/M) would expect.

MPLAB X is based on NetBeans, which I’ve used in the past and found to be a very user-friendly and functional.  Hopefully I’ll enjoy this upgrade, and anticipate much better integration with open source compilers/etc.

It’s assumed that anyone taking any interest in this blog or topic will have a basic understanding of logic.  However, I am going to put forth the convention I will be using to avoid any confusion.

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There are a few things in the world which are being lost on new hobbyists, one being the importance of knowing why an IC does what it does.  I am going to risk sounding rude and arrogant, but any fool can strap a couple of resistors to an IC and make an audio amplifier of marginal (mobile device) quality.  Logic, too, has gone this direction, where no real knowledge of the internals is necessary, only a basic understanding of the truth tables.  For debugging a circuit, this is fine.  But for building  a new one, it is important to understand that a NAND gate is NOT an AND gate with an inverter after it.  It is, actually, an AND gate where your transistors are switching ground.  As it is later than I thought, I will leave you with the there fundamental logic circuits:

It is important to note that these circuits can be used like building blocks, just like the conventional symbols shown below them.  However, it will be demonstrated that a lot of parts and time can be saved by using much more efficient means of achieving the same result.  Your power supply will also be grateful  (This is, after all, TTL logic).  Also, you will not see the OR gate drawn that way again, as it was merely to demonstrate the current paths that made it an OR.

The boys over at DexOS are doing it again, this time with a set of hardware dedicated to the project.  Intel x86 support is not going away, but a new and shiny OS designed for ARM is developing, and is to be targeted for a PDA-sized platform.  Look forward to any number of random devices, the form factor makes all sorts of cool ideas possible, like carputers and home control systems.

Posted in Basic Circuits is a very basic RS-232 driver circuit to use  in interfacing your circuits to a PC via serial port.  Notice I used the MAX233 integrated circuit, to avoid a mass of capacitors and soldering for the novice.  The MAX232 is nearly identical, except for the use of external capacitors.  It is a bit cheaper as well, but does not yield such a compact and clean board layout. http://speedofdark.us/pmwiki/pmwiki.php?n=Projects.Interfaces

I’ve revamped the update method for the site, to make fuller use of my blog and its publishing capability.  All main group pages will now have news feeds driven from the blog.