Lambda colour kit

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user@lab1
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Re: Lambda colour kit

Post by user@lab1 »

Hi,
Forgive my curiosity, which memory areas occupies this interface?
Thanks.
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stefano
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Re: Lambda colour kit

Post by stefano »

The colour layer gets enabled by writing anything to location $3001.
$3000 swtiches it back off.

The Lambda display file is fixed, starting at position $407D (the first byte is a NEWLINE as on the zx81, thus $76).
The attributes file is accessed writing at position $207D, and obviously it can't be read because it overlaps the ROM locations. Characters corresponding to the NEWLINE positions alter the border color.. so probably it is easy to generate striped borders !
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shock__
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Re: Lambda colour kit

Post by shock__ »

Forgive me the thread necromancy, but I was gifted such a device yesterday and have a few questions ...

First of all it appears the interface does work in general when used with a 16K RAM expansion (DIY, SRAM based, WRX enabled) in that I can initialize the color mode (random attributes shown), overwrite them all as recommended in the example program and set individual attributes to my liking. On my ZX81 (Rev. 3, simple transistor based composite mod [not the 'complex' 555 based one which adds a backporch] - probably not required due to a 2C210E ULA, no inverse video - quality on my Sony PVM 9044QM is great) the output quality of the color addon is extremely bad, some lines are distorted, the colors don't exactly match up. Any ideas what could be done to improve the picture or is this something I have to live with?

Picture here: http://i.imgur.com/R4GTBwp.jpg
ZX: Pentagon 48 (as 128) | ZS Scorpion 256 Turbo+ & SMUC + ZXM GS | Compact 256 Turbo 1.1 (Scorpion Timing + fixed Covox) | ZX Spectrum 48K | Sprinter 2016S | Didaktik M (+ RGB) | CoBra | ATM Turbo 2+ 7.11 | Pentagon 1024SL 2.2
gozzo
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Re: Lambda colour kit

Post by gozzo »

something definitely not right, is the tv selecting pal? may be dodgy 4.433 crystal... havent got the schematic of it to hand at the moment so cant say yet....
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shock__
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Re: Lambda colour kit

Post by shock__ »

Crystal is fine, schematic here: http://forum.tlienhard.com/TS1000/www.u ... acolor.gif

Back to the ZX81 it is for me it seems ... while the picture is fine on the Sony PVM it gives me a solid white screen on the Bravia LCD.
Building the back porch/level addon (once again) by zxzigg as of now.

EDIT: Backporch generator enables the bravia to display a proper picture but otherwise makes things only worse.
ZX: Pentagon 48 (as 128) | ZS Scorpion 256 Turbo+ & SMUC + ZXM GS | Compact 256 Turbo 1.1 (Scorpion Timing + fixed Covox) | ZX Spectrum 48K | Sprinter 2016S | Didaktik M (+ RGB) | CoBra | ATM Turbo 2+ 7.11 | Pentagon 1024SL 2.2
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shock__
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Re: Lambda colour kit

Post by shock__ »

I guess this qualifies as working?
http://i.imgur.com/l9SuYyv.jpg

No idea what exactly fixed it ... I added a 1K variable resistor in the footprint set for one (previously hardwired with a fixed resistor) and replaced the orange trimable capacitor (which broke) with a yellow one (too lazy to look up the values right now), also added decoupling caps for every IC.
Color levels still seem to be a little off (have to tune the brightness up to 3/4 instead of the default 1/2) but that's ok for now - I'll stick with tuning the video monitor for now.
ZX: Pentagon 48 (as 128) | ZS Scorpion 256 Turbo+ & SMUC + ZXM GS | Compact 256 Turbo 1.1 (Scorpion Timing + fixed Covox) | ZX Spectrum 48K | Sprinter 2016S | Didaktik M (+ RGB) | CoBra | ATM Turbo 2+ 7.11 | Pentagon 1024SL 2.2
gozzo
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Re: Lambda colour kit

Post by gozzo »

better :-)
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mrtinb
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Re: Lambda colour kit

Post by mrtinb »

Hi :)

I try to understand the schematic of the Lambda Color Module.

I've tried to match ICs on the picture and the schematic.

There is one IC and drawings on the schematic I don't understand. Can anyone enlighten me?

Image
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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siggi
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Re: Lambda colour kit

Post by siggi »

That are 4 analog switches (IC version of a relay). Maybe a CD4066?

http://www.ti.com/lit/ds/symlink/cd4066b.pdf

Siggi
My ZX81 web-server: online since 2007, running since dec. 2020 using ZeddyNet hardware
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mrtinb
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Re: Lambda colour kit

Post by mrtinb »

I thought that might be the case. But since all I ever learned about electronics is from this group, I'd better ask.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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