Z80 computer: LCD text display

[electrodacus]

Love the Z80 CPU my diploma project was using this Z80.

It was and Acquisition equipment with ADC using successive approximations was using 8 resistors connected to 8 digital pins and a comparator to compare the input with the output of the resistors you where starting with 2.5V and see if the input was lower or higher then get the middle voltage from that interval and so in very few steps you get the input voltage.

[TheOneToxic]

this is amazing, but the music is just awful

[FlyByPC]

@TheOneToxic It's royalty-free music and I don't exactly have a Hollywood-style budget. I may try composing my own instrumentals one of these days...

[Curri3Saan]

@TheOneToxic Get stuffed, sounds awesome to me.

[faffaflunkie]

Why not use the Z-80 to control the whole thing, L.E.D.'s and all. It (the Z-80) is fast enough. Open up a modem or a consumer device and half the time you will still find a Z-80 or one of it's clones.

[FlyByPC]

@faffaflunkie True, but I'm more familiar with PIC programming, and interfacing it directly from the Z80 would have entailed support circuitry anyway (since only the 8 data lines are available, and something would have had to toggle the two control lines to the LCD). I know the Z80 is ubiquitous, and still quite capable as an embedded CPU. PICs are just easier to interface directly to peripherals (since they're microcontrollers and intended for that purpose.)

[ZXRulezzz]

How did you hooked LCD module to Z80?

Did you used some kind of PIO chip for this? (i8255?)

I'm assembled simple Z80 system myself, so now I'm trying to hook up KS0108 compatible 128*64 graphics display to it. I tried to connect it directly do Z80 bus, but I had no luck...

[FlyByPC]

@ZXRulezzz I used a PIC microcontroller as a custom LCD interface chip. The PIC handled the LCD logistics -- the Z80 program writes a byte to I/O address 0x00 to send it to the LCD as a "control" byte; it writes to I/O address 0x01 to send it to the LCD as a "data" byte (to be displayed). The PIC handles setup and the LCD control lines.

The 128x64 display sounds harder; if it's like the one I've used (see my other video), it is graphics-only, so you have to create the text manually. Good luck!

[Robobbly]

cool!

[stewartdahamman]

I heard that alright, but see, to write to a display from a z80 , do you need another z80 to control the display ????

Im sure that sounds ludicrious, but i have no real knowledge of microprocessors , but i will next semester ! im doing electronics engineering you see.

what made me think that this was that the z80

wasnt powerful enough like a pic to drive a display and do something useful all by itself.

Continued below.......

[FlyByPC]

The Z80 could drive a LCD display by itself with some additional logic chips (latches, pattern-matching discrete logic etc). It's easier to set up a PIC to accept commands and data from the Z80 and offload a lot of the drudge work. (This Z80 computer is programmed by hand in hex machine code, so writing complex display drivers would be a real pain.)

[stewartdahamman]

Ah rite, you would need to amny external chips then, the pic has all these intergrated then.

Yeah, i was thinking that your machine worked on hex, that really would be a pain !

well, thanks for the info my friend,

stick with it and i hope to see you at lesat getting it up to C level ! :) :) :)

[FlyByPC]

Actually, I had thought about writing a very simple BASIC language for it... 8-)

[stewartdahamman]

As you do ! :)

Well thought was the right word, because such projects usually dont get any further !!! :) lol

[stewartdahamman]

savage cool, i didnt know a z80 could do this much, saying its such an old chip

[FlyByPC]

Thanks. Actually, the Z80 can do quite a lot; it can directly access 64K of memory. A modified version of the Z80 was used in the original GameBoy.

[stewartdahamman]

also, is your ordinary z80 chip that you can buy for a whole 50cents, really exactly the the same chip as was used in the heart of sinclair z80's etc. ?

sorry about all the questions, i really enjoyed your video.

[FlyByPC]

Yes, a Z80 CPU was the actual CPU used in the Timex-Sinclair. (I have one which I've taken apart several times.) Sinclair did use a few other accessory chips -- RAM, ROM, and a custom video-processor chip.

[Keijz74]

I have a gameboy Advance. It has a Z80 related CPU next to the ARM, so you can play the original GameBoy games on it. They're still fun :o)#

[metasuperhyper]

one word: cool.