Acorn Atom Replica build

[stephen_usher]

Annoyingly IC1 and IC3 are the same and I only managed to order one of them... :sigh:

Been there. Done that. (Ordered just one 74LS166 when needed three.)

[rubber_jonnie]

Annoyingly IC1 and IC3 are the same and I only managed to order one of them... :sigh:

Been there. Done that. (Ordered just one 74LS166 when needed three.)

Unlikely going to be the last time it happens I expect...

[rubber_jonnie]

OK, so the colour board is built:

IMG20260414170700.jpg

I've not had time for a proper test but it does a least output just fine via the composite output of the Colour Board.

I'll need to rig up something to test the YPrPb and RGB outputs next, but that'll have to wait as I'm up at 05:30 tomorrow and want to go to bed now!!!

[rubber_jonnie]

Well happily I have been able to check all the colour board otputs with my scope and everything seems to work as expected :)

I get good video/sync signals from RGB, and good video and sync signals from YPrPb and composite, so next up I need to try and get them hooked up and tested on a colour display :)

[rubber_jonnie]

OK, so happily I have a spare 6 pin din socket that I can use to build an RGB cable for the colour board that will work with my BBC B RGB SCART cable.

Connections are as follows:

R.gif

So it should be fairly simple to get wired up today.

I'll report back later.

[rubber_jonnie]

Cable made:

IMG20260419110724.jpg

IMG20260419112506.jpg

And it works!!! It is still NTSC though which my TV isn't 100% happy with.

IMG20260419114005.jpg

The Atom now has colour out and it is highly reminiscent of the Dragon 32 and other machines that use the 6847 like the Tandy CoCo, as can be seen in the frogger screenshot. Basic screen is now green as expected :)

There are 3 pots that are all set in the middle, I believe they are RGB pots so I may tweak them a little. Will have a look at that later. Definitely considering building the Atom RGB2HDMI that cam with this board from @PhilC.

[stephen_usher]

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[rubber_jonnie]

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🤣

It is indeed.

[rubber_jonnie]

And just for kicks I'm building this:

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The XC9572XL-10VQG44C is quite expensive on eBay so I'm taking a punt on Ali Express, lets see how that goes...