z80.. might be another pointless thread

Got questions? Got answers? Go here for both.

Moderator: MaxCoderz Staff

Post Reply
mnc2fan
Extreme Poster
Posts: 441
Joined: Fri 11 Mar, 2005 4:32 pm

z80.. might be another pointless thread

Post by mnc2fan »

Anyway. I'm not sure if it's the z80 based ti calculators, or something else, would be a good thing to use what I'm wanting. I'm wanting to learn the way processors, well computer based hardware, actually function. Reading books, meh. Hands on, maybe even building a z80 or similar type of computer.

I know I can probably find this answer out really easy googling, but I'm seeing a dying forum in need of some help. Well, I'm trying to be the help.

Serious question though.
<ahref="http://spreadfirefox.com/community/?q=a ... t=73"><img border="0" alt="Get Firefox!" title="Get
User avatar
benryves
Maxcoderz Staff
Posts: 3087
Joined: Thu 16 Dec, 2004 10:06 pm
Location: Croydon, England
Contact:

Re: z80.. might be another pointless thread

Post by benryves »

Building a Z80 computer isn't especially difficult, though you should probably have a rough idea how it works first. Electronics Explained is a good book that covers the basics of microprocessor circuits (and is a great book otherwise). I'm currently revising my design to use more microcontroller support, including a PIC to drive a 320x240 LCD (instead of a 128x64 LCD attached directly to the Z80) and a flat 64KB RAM that is initialised from external storage by an AVR at boot time (instead of a boot ROM - this will allow me to run CP/M).
mnc2fan
Extreme Poster
Posts: 441
Joined: Fri 11 Mar, 2005 4:32 pm

Re: z80.. might be another pointless thread

Post by mnc2fan »

Again, I know a simple search would easily find me the asnwers.

I believe I came across a forum where someone was talking with you, or searched for something about your z80. Actually they were going on about the SymbOS, and seeing about the possibilities of running that on something designed similarly to the cpc (not sure what the brand was).

I was really impressed with what a z80 is actually capable of. Full windowed GUI with multitasking support, and color screen. Very impressive!

Anyway, are did you source your parts from old electronics, as far as IC, and memory chips, or are these things you purchased from surplus electronic shops? Kind of curious, because I actually am having a tough time figuring out where to get all these parts so I can begin compiling things together to build one.
<ahref="http://spreadfirefox.com/community/?q=a ... t=73"><img border="0" alt="Get Firefox!" title="Get
User avatar
benryves
Maxcoderz Staff
Posts: 3087
Joined: Thu 16 Dec, 2004 10:06 pm
Location: Croydon, England
Contact:

Re: z80.. might be another pointless thread

Post by benryves »

I guess the thread you are referring to is this one? The CPC was an Amstrad computer. :-)

Sourcing parts isn't too easy, unfortunately, especially not on a budget. Graphical LCDs are notoriously expensive (hunt around eBay for deals, though without an on-board controller and RAM they are relatively painful to work with). Sourcing parts from old computers (e.g. video controller chips) may be a good plan. I buy most of my components from UK-based suppliers, but Farnell and RS Components are international. I understand Mouser and DigiKey are good in the USA, but they charge too much for postage and packaging to the UK to be economically viable for me. Finding parts in DIP is increasingly difficult. Values may also be a bit odd - I haven't been able to find 64KB SRAM chips, though 32KB and 128KB ones are very easy to find!

I'd recommend you took a look at microcontrollers a little first, personally. These are complete microprocessor systems (including the CPU, ROM, RAM and various bits of hardware such as UARTs for serial data transfer) in a single chip. I understand that the Arduino development platform is popular as an all-in-one system, though I haven't had experience with it myself (though I do use the chip that it is based on, the ATmega168, a fair amount in my own projects).
mnc2fan
Extreme Poster
Posts: 441
Joined: Fri 11 Mar, 2005 4:32 pm

Re: z80.. might be another pointless thread

Post by mnc2fan »

Looked up one microcontroller kit, then I got side tracked on what all you can do with those things, it makes not appear so intimidating. I believe it was the ATmega168. Not too bad for a kit price, well without me looking at more than that one kit it seemed reasonable. Had a screen, controller chip, breadboard, with wires needed.

What does that ATmega168 use as programing? I know it comes with a boot loader.

I do remember as far as suppliers go, in the USA anyway, the distributor I work for buys from Tyco. I'll have to browse their site and see what they have in the way of chips. I think they mostly manufacture sockets, and connectors though..
<ahref="http://spreadfirefox.com/community/?q=a ... t=73"><img border="0" alt="Get Firefox!" title="Get
User avatar
benryves
Maxcoderz Staff
Posts: 3087
Joined: Thu 16 Dec, 2004 10:06 pm
Location: Croydon, England
Contact:

Re: z80.. might be another pointless thread

Post by benryves »

The ATmega168 supports a bootloader, as do most modern microcontrollers, but if you buy one it'll come blank so you'll need a programmer of some description (I use a variation of the SI Prog). The Arduino comes pre-programmed with a bootloader so you can just plug it into a USB port and get going.

Like most microcontrollers, AVR development can be done in assembly for free. There is also the free AVR-GCC, which allows you to write code in C. (See WinAVR for the Windows version). Most other microcontroller families will have a shareware C compiler, which will have some restrictions unless you buy it (e.g. they will have a code size limit and/or will not optimise the code).

If you're looking for a very cheap microcontroller to get started, there's the STM8S-Discovery. This gets you a microcontroller, programmer and debugger all built into a single demo board for $7. Unfortunately, the documentation isn't all that great, though I did write a fairly lengthy tutorial for it. To do more interesting things with the microcontroller you'd need to buy other parts and plug them into the pin headers on the demo board, but it serves its purpose as a very basic introduction.

The PICAXE series are aimed at the education market. These have fantastic documentation and are really easy to work with, though you'd need to buy more equipment to get started with them. They are essentially regular PIC microcontrollers with a preprogrammed BASIC interpreter, offering a huge amount of functionality built-in at the price of reduced performance (they are still more than fast enough for a wide array of different projects, but if every clock cycle counts then they're probably not for you).

Incidentally, I was recently speaking to someone who'd seen my Z80 computer and was interested in running BBC BASIC on their own machine. Rather than build a fully-fledged Z80 computer, which would involve lots of different chips all wired together, they ported a Z80 emulator to a PIC microcontroller and ran everything on that single chip. Cheap modern microcontrollers can easily outperform much more expensive designs using older parts!
Post Reply