im wondering, how hard would it be to add this to an electron

roy_bates

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just tossing around thoughts.so here goes

im wondering how hard would it be to add a SN76489 to an electron,and by wonder i mean a in a complex way i imagine it is
but,realistically is it possible

yes,its a serious question,from a discussion point of view

not a thread saying ,show me how and where are the schematics,but as a pondering thought :)
 
I suspect there are those more knowledgeable than me but FWIW:
In theory why not? The Beeb has one and it should 'just' be a matter of power and support circuitry which can be mostly lifted from the Beeb's schematic. I can think of one or two 'gotcha's' off the top of my heard, there may be more:
-Some of the addressing in the Elk is different / more restricted than the Beeb. If the IC has to live at a 'non-standard' address that's going to limit software compatibility
-The 'OS' will need some rewriting in places, possibly return the Beeb code, to be able to drive it. Unless directly banging the metal is the plan
-The Elk handles it's more limited sound via the ULA, I imagine a SN76489 won't just need power & addressing but the whole hog on the output side too
-With the ULA being a single device handling almost everything the Elk does, including sound, I wonder if it's going to be as 'simple' as addressing a new IC or is the ULA going to get in the way, so to speak

I'd certainly be intrigued by the idea of an Elk with a proper sound chip, assuming it was useful. I wonder if far more knowledgeable peeps over on stardot.org would have some more useful thoughts? I do remember that's been some discussion about a replacement / upgraded ULA for the Elk which may shed further light on technicalities.

I hope that helps a bit.
 
a few of those points did cross my mind,i could give it a go i have most of the parts already if i wanted to tinker for bit
it wont matter really if it doesnt work

the elk has alot of limitations,i know when i repaired this one it has a really odd memory interface

i might try stardot,if its a no go,then fair enough i dont really see it as a hassle
 
Other than a 5V supply, a clock and a small audio amp it doesn't need very much to get it "singing". How about connecting it to the printer port of a Plus 1, or connecting it to a cartridge slot? That way all or most of the address decoding is looked after already.

Bryce.
 
on a cartridge port sounds interesting,that did cross my mind also,generating a clock wouldnt be very difficult,i think this needs 4mhz
 
A cartridge soltion would probably need more hardware than a printer port solution. Regarding the clock, this can be stand-alone (ie: not synced to acorn clock), so an onboard crystal will sort that out and the printer strobe signal can be used to set the /WE pin of the SN76489.

Bryce.
 
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