Emulating the CPU is usually a natural first step. The VT100 hardware is orchestrated by an Intel 8080A CPU with 8K firmware ROM and 3K RAM in the basic configuration.The 8080 is a small, simple 8-bit microprocessor, and I was able to whip up a...
ln the last episode (Generate the Flash's contents with a recursive algorithm), I defined the general algorithm to generate the Flash's contents. It accepts arbitrary permutations. Now, the question is to generate the proper permutation vector.From what...
I got the RAM board all wired up, and it works correctly. It doesn't work as it should, but it works as it's wired. Just look at the schematic:And then think about the 8080/8085/Z80 and how they interact with I/O. That's right. If I write or read to...
I recieved my hd6309 SBC bridge PCB right around Easter time. This is just a small PCB that interfaces to the expansion connector on the SBC. It brings the address, data, control lines through 5V to 3.3V level shifters (74LCX541 and 74LCX245 do the work...
The CPU is a “Von Neumann” one (as opposed to Harvard), for simplicity. There is only one external bus (data + address), for all memory and peripherals. The 16bits words are organized as “little endian”, because I think that...
To keep it short : life is life. Demanding baby. Lot of time spent on solving problems at my job. Too much tired to work on my projects. But at lest i solved nearly all of the stacked problems at my job and my little boy gave me some space. So 6 weeks...
It works! There's still a lot of cleanup left, but it seems to be running correctly. This test program exercises every instruction. The vertically-oriented breadboard is unnecessary for the CPU to function, it's just a breadboard for I/O.
I have a stable PI image with Sense-Hat (I built a cool new little project for gauging temp of the unit , surrounding temperature, ... , I will use the joystick to allow a user to access any of the attributes on the 8 x 8 led's), GNURADIO, RTL-SDR, Bitscope,...
I was having intermittent CPU issues. These manifested as intermittent results uploading S-Records. Sometimes I'd even make an identical build which would work one time but not the next. Something was marginal in the design. I hooked up a logic...
The last log Orbital mechanics tried to map the structure of the orbits and found very interesting data, but the mapping program was obviously missing important clues. So far I have uncovered two orbits and a long trajectory leading to the first largest...
This is a dense little board. It has as the standard bits a floppy controller needs like the WD2793A which is the goto chip. The very interesting part is that this board has RAM, ROM aaaaaand a full 8088 x86 CPU. The 8088 is another one of those...
Two posts ago our CPU was demonstrated connected to an Arduino to provided memory-mapped I/O. This MMIO space could hold code, other board-level I/O functions or perform functions on the host PC. The 'memory' area of this MMIO space was slow - each access...
Just a week after teaching a workshop at ACT Festival in Gwangju, we repeated and expanded on the experience and examples in London, built a 8-step / 2-track sequencer using the buttons on the Korg NanoKontrol MIDI controller and its faders to control...
The Atmega 8 can't do an interrupt through the WDT module. It only can do a direct reset of the whole CPU. So this way to wake up the CPU from the sleep isn't practicable. Another way is to run the timer with an external clock in the sleep mode and generate...
I left this great bomb for myself in August: // The Timer1.stop()/start() is bad. Using it, the display doesn't // tear; but the audio is also broken. Taking it out, audio is good // but the display tears. Timer1.stop(); ... Timer1.start(); Of course,...