7 Segment LED
Here’s a job that sounds reasonable enough: connect an 8-wide dip switch to a pair of 7 segment LED displays, so that the 8-bit binary number on the dip switch is displayed as a 2-digit hex number on the LED…
Universal Programmer
I got a TOP 2007 universal programmer yesterday, for burning EPROMs, GALs, and Flash memory. Whenever I hear the term “universal programmer”, I imagine a nerd-equivalent of the 1992 movie Universal Soldier, starring Jean-Claude Van Damme. Plot: a mild-mannered C++…
Schematics
I’ve started creating schematics for the machine, using an evaluation version of CSiEDA 5. Making a real schematic that shows all the parts, pins, and interconnections is amazingly time-consuming, but it’s essential if I want to avoid making construction mistakes.…
Final Design Tweaks?
I’m trying to finish up the final hardware design now, so I can get started with actually building this thing. Although it will probably never be truly “done”, I don’t want to end up ripping out half the components and…
Protoboardin’
My long-awaited delivery of hardware arrived yesterday, including a protoboard, tools, and about half the components I need to build the machine. I’m using the protoboard to try various test circuits, before I construct the real thing on the wire…
Max Clock Speed
I used Verilog to do a simple test to estimate the machine’s top clock speed. I kept increasing the clock rate until the validation test suite started failing, and it topped out at about 2.63MHz. That feels respectable for a…
Microcode 1.0 Complete
Time to celebrate! I powered through the remainder of the microcode for the core machine instructions, along with a full test suite to verify each instruction, and it all works. That’s 50 different instructions, and a couple of hundred individual…
ADC $NNNN,X
Uh oh. I was cranking through the microcode implementation for BMOW’s instruction set, making good progress. I’d finished about two-thirds of the microcode, when I came to ADC absolute, X-indexed. That’s when the wheels came off the cart. This instruction…
Optimization, or Distraction?
I think I may be getting too concerned about potential optimizations to the hardware design, before I’ve even built or simulated the initial design. A couple of possible optimizations occurred to me recently. Improved CC Register: I described earlier how…
Page 86 of 88