MH6502 - Decode Logic (Ep3)

Comments

Post a Comment

Popular posts from this blog

First things first

Image
Before starting my adventure, I needed to do 2 things. Reorganize my lab space, and buy the necessary components. I wasn't quite ready to start my project, space-wise, as my office/lab was a mess and all my existing components were all thrown in various bins haphazardly.  Step one , reorder the furniture and optimize my desk space. Easier said than done, but I managed to do it in less than a day. Keep in mind that my "office" was also a dumping ground for everything else in the apartment. So I made some hard choices on what had to go and what stayed,  Mari Kondo style. It's not perfect, but it's a start. The following day, I sorted all my components, mostly because I was curious to find out what I had. And hold and behold, I had many unnecessary duplicates. That's what happens when you let me loose in my local electronics store without a shopping list or a plan. Step two , order the components needed. I chose Mouser because they carried the WD65C02 microproc...
Read more

To PLD or not to PLD

Image
When I start something interesting, I tend to overdo it. I originally contemplated using standard gates for my glue logic. But then chose to go the EEPLD (Electrically Erasable Programmable Logic Device) route. Wow, was I ambitious? Not only I was to build the 6502 single-board computer from the ground up, but I had to also get to know PLDs up close and personal at the same time. Well, it turns out it's not all that hard, if you find the right tutorials on the web, and if you have a precise memory map defined. I had this really particular memory map planned. But for my second iteration of the SBC, I opted to go simply and work my way up.  The map, for now, is 32K ROM, 16K IO space, and 16K RAM. This will change in the future. And this is the beauty of PLDs, there is no need to rewire anything. It's just the software that needs changing. I chose the ATF22V10C, a G22V10 equivalent, because of it's many input and output options: 12 dedicated inputs, and 10 configurable input/o...
Read more

The dawn of a new adventure

Image
In comes the insanity!  Well, that's it! I'm not one of "those" people that reminisce and rides down memory lane in the nostalgia bandwagon. Yes, my mid-life crisis has gone and past. But I find myself wanting and yearning to have a good start in a new hobby, micro-electronics. And what better way than to start building an 8-bit microcomputer. And yes, I do dabble with microcontrollers also, so I have a good start. When I was in school in the late '80s I learned to program on the  6809  in assembly language on a single board computer (SBC). My initial thought was to recreate the aforementioned SBC, but the availability of parts is diminishing. In comes  Western Design Center , makers of the new  WD65C02  chips, still in production today.  Off the shelf components is important to my endeavor, in case I want to replicate my design. Trying to scrounge vintage and obsolete parts is not part of the plan. So, welcome to my insanity project, keep in touch, an...
Read more