All of the buildings, all of those cars
were once just a dream
in somebody's head
Mercy Street - Peter Gabriel
Setting up the 6845 involves filling in 16 registers so that the 6845 can generate the correct timing signals for the desired resolution. The available data sheets provide more information on how to calculate the needed values. But since that’s a tedious process, I decided to write a small Python application that could calculate those values for me which you can find below and which was surprisingly accurate. Only R7 (Vertical Sync Position) was of a little bit of sometimes and needed a…
The design I came up with probably contains few surprises and is inspired by various designs that are floating around on the internet.
After a long hiatus, which is easily explained as I’ve been working on my most complex project yet. And even more nostalgia I’m afraid… For the last few months I’ve been working on creating an old fashioned video terminal (circa 1980’s) using chips of that era as well (I inherited a ton of TTL chips when my work decided they didn’t need their small electronics lab anymore.). It’s my first digital project in decades and it might still be a bit rough…
More nostalgia… A few weeks ago I bought the, RC2014 compatible, SC203 Modular Z180 Computer Kit for RC2014 kit on Tindie which uses the Zilog Z180, 512K fast static RAM and 512k ROM (loaded with ROMWBW). To this I added a Compact Flash Module as well for mass storage. With these components it’s possible to create a CP/M compatible system (just add a terminal) running on real hardware of that era.
A few years ago, Elektor Magazine had an interesting DAC project with high end aspirations based on the Burr-Brown (now Texas Instruments) 1794 DAC for a modest price.
Cocoacrumbs