September 2012

Inverted DASA serial cable for AVR programming

Just thought I’d post this up here for “backup” purposes… lately I’ve been doing a lot of AVR programming, the first step of course was to procure a programmer for the devices.

The following is a schematic for the programmer I have built myself. It can be built out of scrap bits, none of the components are critical in value.

It gets its name as it is essentially identical to the “DASA” serial cables, only all the signals are inverted.  The inverting buffers serve to provide voltage level conversion along with crude tri-state functionality when the AVR device is not being programmed.

Inverted-"DASA" serial programming cable for AVR

Inverted-“DASA” serial programming cable for AVR

The design is released under the TAPR Open Hardware License.

Setting up dead-keys without a desktop environment

Over the years I’ve used many a desktop environment or window manager for my graphical desktop. In the beginning it was FVWM (1.x), a later update brought me AnotherLevel (basically Red Hat’s branded FVWM), I also toyed with OLVWM, WindowMaker, AfterStep, CTWM and a few others.

KDE was one of the few that I’ve used long-term. I loved KDE 1.0 when it was first released. Gnome 1.0 came out, and I soon switched over, but it was only a matter or a month or two and I was back to KDE. Likewise with XFCE, did try it for a little while, but then I returned. Lately, KDE has been getting a bit bloaty for my liking. Thus, I’ve been on the window manager trail, and for now, I’m back with FVWM.

This has worked well, except for one bug bear; I could not get the compose key to work. So I did some digging, and came up with the following:

setxkbmap -option compose:rwin

Add that to your .xinitrc, or you can do what I did, and add it to the FVWM start up scripts:
AddToFunc InitFunction
# Load the X Setup Scripts setting if we use it
+ I Exec [ -f $HOME/.xinitrc-fvwm ] && sh $HOME/.xinitrc-fvwm
+ I Exec exec awsetbg -a -r /home/stuartl/backdrops
+ I Exec exec kmix
+ I Exec exec klipper
+ I Exec exec blueman-manager
+ I Exec exec xscreensaver
+ I Exec exec setxkbmap -option compose:rwin

When you re-start your session, you should find the right logo key (“Windows” key, or in my case “Command” key, yes my machine is that fruity) will deliver the dead-key magic.