Snagged an Aurora!

[Chr$]

Worth more than £100 Derek. I'd buy all you have for £100 each! It's subjective of course and there are a few factors (like any thing old and offered for sale). They are rare but demand is also low as there aren't many people that even know what they are or would want/need one. They are complicated and require other equipment (e.g. Gold Card) and some work to set up and test - especially if you have to make leads - which may be beyond the abilities of many. They are technically brilliant and probably one of the ultimate original QL upgrades (at a push I know, because fitting them in an original case is quite a task).

Does anyone know how many were made or sold?

[dilwyn]

Price is usually subject to availability - such boards are not cheap when there is a demand (due to failures or new people wanting to revisit older designs), but £1000 is taking the proverbial - and explains perfectly why he hasn't sold it yet - he's got quite a few watchers but no bites - surely that tells you your item is mis priced...

I sell quite a few non-QL things on eBay (mostly Welsh records). The price some people try to sell those for is also taking the proverbial. The sellers seem to think that sticking the word "rare" or on it magically makes the price into hundreds of pounds. I guess if they're not in a hurry to sell, they just think of sticking a very high price on the item and sit back and wait. They do disappear after a while, but whether they've failed to sell or gone to rich collectors in the far east, I don't know what happens to the high price items.

So I agree, some people do take the proverbial on eBay.

[Derek_Stewart]

Hi,

I was given the Aurora PCB files, which created in an old Protel CAD format, I imported this into Altium Designer, then into KiCad 7.

The Aurora is a 4 layer PCB, where the inner layers are the power and ground signal layer. In the original Aurora PCB file which was created in a primitive CAD program, compared to modern standard CAD programs. There seemed to be no way to create the inner layers correct and what I was given was a series of polygons representing the respective plane and the inner track connections.

Since I am not a CAD designer, I had to learn all about the PCB design process. I managed to re-construct the inner planes, to validate PCB track seteup, I started adding the track Net names, which should highlight any errors.

The final validation to to reconstruct the schematic diagram and link it to the PCB, a reverse way of working.

There is an Aurora schematic file in GIF fornat, which I am in the process redrawing and comparing to the existing PCB file. But there are some errors in the schematic, which I am trying correct from the existing Aurora hardware.

I had thought, this not worth the effort, but maybe an updated Aurora could done..

[Pr0f]

Derek - it may be nice to put the 2 resistors that are on the back of the aurora board back on the top layer - there is a 1K8 resistor under the IPC and a 2K2 resistor that is tied between VCC and reset out line - I think there is room to put these on the top layer somewhere.

I also notice that the schematic says the video resistor packs are 8 pin, but the board is laid out to take the more common 9 pin resistor networks - it's not an issue of course - just might be something that can be annotated on the top silk screen layer if you do one.

[Derek_Stewart]

Hi,

Since I have not much hardware to build, I will look into this.

Please bear in mind that there are errors on the Aurora Schematics GIF file, which I am in the process of correcting.

I have to compare the PCB file to the actual Aurora boards, I have to fix the schematic errors.

This is a convoluted way of PCB display, but reverse engineering always is.

I also have to understand the MACH chip code which is in Lattice HDL lanugage that may pre-date Verilog or VHDL. But then I am guessing, in the words of FogHorn LegHorn, I will have to do some reading of the "Long Haired Book"

[Pr0f]

"Long Haired Book"

Love it.

I've been having a good long look at that code.

QAG - that seems easy enough to get your head around
MAC - this one's quite busy - but the code is laid out in useful sections - and once you get your head around having to register certain signals / flags to sync them up, and the elegant state machine for memory access - it actually makes a lot of sense - it's the weird and wonderful logic around handling all the different video modes and selecting the required clocks - made complicated by the 'need' to support legacy video standards and all the various formats that you could have possibly plugged in to the card.
PE - not so bad - but it's more of the same along with the MAC - because this is your main Pixel engine - and needs to play some interesting shuffling to handle the conversions between 16 bits of video definition and a stream of pixel values.

Nasta also broke some of the definitions up so that the mach compiler could have more choice in placing the code within the CPLD.