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I don't really know how your setup works, but producing @ on a PC keyboard usually involving pressing shift, which may interfere with the logic at the Dragon end. Also is it coincidence that @ vs " is one of the differences between US & UK keyboards? What happens if you type into a text editor inste...

Brilliant stuff! It recreates the purple shimmer on the PMODE4 display beautifully :) To complete the Dragon video experience we would need a small and very slow drift on the colour frequency to simulate the machine warming up! @Alistair Chroma highpass can be set to zero or 0.25 to simulate the eff...

I would have expected some kind of video display i.e. something with a border. The vdg will generate sync signals with just a clock input, except when something is pulling the CHB output down to ground activating a test mode. I've seen this happen once due to a bad ceramic cap. The video circuit req...

sixxie wrote: ↑Mon Apr 11, 2022 3:08 pm nice one which level?

Level 19. MIght have got a little bit further but had to play standing up.

I then played Doom for half an hour and gave myself motion sickness. Guess I'm starting to feel my age

We had a family afternoon out at the recent OLL '22 Video Games Convention as it was close to where we live. The Centre for Computing History had quite a large presence and I was pleasantly surprised to see a D32 set up with Chuckie Egg. Of course I felt obliged to put my name on the high score tabl...

Curious that it works in a D32. Can't really say much else without seeing a schematic and more detailed measurements.

Assuming you've followed the build instructions to the letter, the ball is very firmly in the court of the supplier and/or designer.

I would use an oscilloscope to see how much ripple there is on the supplies. The fact that it works when more current is drawn suggests one of the supplies is moving to a more stable region, which in turn suggests an incorrect component value. A component value could be incorrect because it was put ...

Hmm, strange one. In my experience, jail bars on Dragons are usually caused by missing bypass caps on the DRAM array, and fitting all eight 100n caps virtually eliminates them. I don't think I've ever seen hum bars on a Dragon. That tends to indicate a fault, particularly if you say 1u caps didn't m...

Love the artwork! Brilliant

Cool. Thanks for sharing :) There is an old trick for converting a binary digit to ascii hex that is fewer bytes than the branching version: adda #$90 daa adca #$40 daa Also, I wonder how the long multiplication compares with a version that uses 6809 MUL (8x8) to generate the partial products.