DIY Z80 Computing

[waeV]

And where did you get the materials? I have a Beginner's Electronics kit with resistors, capacitors, and all, but I'm particularly interested in finding out where you got the screen.

[benryves]

The LCD was from Rapid Electronics. Some other parts were sourced from RS Components, the Z80 was from Farnell.

[waeV]

Ok "color LCD Module" returned some results that were more on topic.

Check out these color screens!

http://www.lcd-modules.com/color-LCD.htm



Do you think it would be possible to run something like this on a battery source? I guess all you'd need is the correct voltage.

Hmmmm...

[benryves]

The biggest drain on mine is the backlight. The LCD itself has a typical rating of 6.77mA at 5V. The backlight has a maximum rating (ie, full brightness) of 975mA at 4.2V.

[waeV]

Hmmmm... i can't find any info on the drain of these LCDs. After some research I decided I would get a TFT LCD rather than an STN one. Color and refresh speed seem to be better.

A 5.7" screen ought to do the trick, with a resolution of 320x240. It says the input is "Digital 18-Bits parallel RGB," so I suppose I'll have to figure out what that means and how to interface with it. But I should be working on my college essay...


Even better parts repository:
http://search.digikey.com/scripts/DkSea ... &keywords=

[benryves]

Digi-Key are based in the US, which incurs a rather extortionate P&P overhead (Rapid and Farnell are free within the UK once you've made up the minimum order). As I'm sure you noticed the sites I linked to were all UK-based, so probably not all that useful for you. (RS Components and Farnell are international companies, though, and will have a US base).

To work out what sort of LCD you need you'll need to work out how it's controlled. The one I'm using has on-board RAM and a controller so all you need to do is send it the data to display via its 8-bit data port.

[waeV]

Well, yes and no. The sites you referenced weren't useful for ordering from, but they had a lot of keywords that helped narrow my search.

Well, I want to end up running SymbOS, so I need some sort of display that supports 4 colors and a 320x200 CGA resolution. Your advice about knowing the controls is good, however. I'll need to look into that.

[benryves]

If you can find the datasheet for the LCD, that should have all the info you need. Mine is a PG12864LRS-ANN-H, and page 9 onwards lists the commands. By checking that out first I had a pretty decent idea of how I could use the device!

I don't know how SymbOS needs to talk to the display, but you may be able to find a video display controller that provides RGB output that you could (for example) hook up to an LCD cannibalised from something like a pocket TV.

[waeV]

Hmmm... symbOS is closed source, and has separate compiled versions for specific machines. I'll get it running in an emulator and try to see what it needs to run.

[waeV]

Found this, but it looks like cheating: It's a pre-built modern CPC clone.

http://www.symbos.de/trex.htm

[benryves]

Being closed source makes life rather difficult. Building a CPC clone sounds like the most practical solution in that case.

Failing that, there's always Contiki.

[waeV]

Hmm... that looks interesting. And internet enabled?

Is it for the z80? Or does being open-source mean that that wouldn't matter anyways?

[waeV]

http://www.sharpsma.com/Page.aspx/ameri ... 050Q5DR01/

This is the closest I've gotten to what I need, and I can get it on eBay for $25, $11 shipping (That's about 45 euros). It can be returned for the $25 back, but I would have to pay for shipping back and wouldn't get refunded for the initial shipping, so I would want to be sure that I could use it. Let me know your thoughts on it, I'll keep researching.

[benryves]

Is it for the z80? Or does being open-source mean that that wouldn't matter anyways?

There is a Z80 version, yes. I believe Contiki is written in C.

so I would want to be sure that I could use it. Let me know your thoughts on it, I'll keep researching.

I think you need to drive that LCD yourself. That is, you'll need some external hardware to generate the synchronisation signals and constantly refresh the screen by pumping in the value for each RGB element.

Ideally what you need is some sort of LCD that has a built-in controller and RAM, so all you need to do is write to its RAM when you want to change is on the display.

[waeV]

I can't find anything. Most websites that sell this sort of stuff only sell to businesses and have a minimum purchase number, and I can't find good info on the ones that do sell to consumers. I haven't abandoned the idea, though, and thanks for your help so far.

I posted on this topic at ubuntuforums.org, and got a few interesting replies...

if i were you, i would check out netbsd and learn some z80 asm.

Actually, z80 asm lead me to this topic. Why NetBSD?

While NetBSD doesn't run on z80 (as noted above), it does run on some fairly cool stuff...

http://www.embeddedarm.com/software/arm ... oaster.php