Not quite available yet

Graynomad:
I'm going back to my Z80, I understood that.

I've still got "Programming the Z80" by Rodnay Zaks on the bookshelf. I keep thinking that somehow it might still come in useful in the future, but I'm not sure exactly how. :slight_smile:

My copy is long gone, that was in another life. Every time this comes up I say I'd like to make a retro Z80 board. One day.


Rob

Graynomad:
I just wish I had an immediate use for an 800 it looks like such a great chip. But I'm up to my arse writing low-level drivers for the LPC1227 at present.


Rob

I know, I'm trying to figure out something too. I did go so far as to download the datasheet and user's guide. I might have to try one out anyway. If a person wanted to get started with LPCs, do you think the LPC812 is as good as any, or is there a model you'd suggest? I'm really interested to see the pricing on these chips, I wonder how far off they are. The datasheet still has some TBDs in the electrical characteristics! The switch matrix is a very cool feature, I've wondered whether anyone did such a thing; now I know. Makes the 8-pin DIP a little more understandable, I think I'd still go for one of the 20-pin packages just for general goofing around though.

do you think the LPC812 is as good as any

Probably, although it's note available yet. Although as was pointed out above the LPCXpresso board is and to start with that's all that matters. The LPCXpress system is very good.

or is there a model you'd suggest?

Well I'm pretty much into the LPC1227, at 48 or 64 pins and with 2 UARTs I find it's about right for what I'm doing now. I liken it to the Mega1284 which I think is the best AVR around. I like those chips so much my current PCB has one of each :slight_smile:

I've written a lot of code for the 1227, originally just to learn the chip but it's slowly turning into a proper Arduino-style HAL. See here

http://lard.robgray.com/index.php

I've spent the last couple of days getting the serial Tx working, it's all FIFOs and interrupts and an unfamiliar chip but it's going now. See here (my 3-day old blog) for today's trials

So, at the risk of being biased I'd recommend the 1227, but one thing I like about the LPC range is that they go from 8 to 217 pins so there's something for every one.


Rob

Thanks for the links and info. Will let you know if I make the plunge/progress. I see the LPC812 has no ADC, but depending on, that's not a show-stopper.

I see the LPC812 has no ADC

If it wasn't for that it would be the perfect small processor IMO.


Rob

There are a few factors to consider:

  1. resources: NXP is quite stingy when it comes to onboard resources. Some of the ST chips for example have 20+ timers, and the nxp chips tend to be limited.

  2. retargetting: you don't typically know the eventual target for your code. For a development board, you want a chip that is as big as possible. 1768/69 are fairly popular for that reason.

  3. debugger: you want to use a fairly standard debugger (jlink/ulink). I would be worried about some no-name debugger.

  4. ide/support: if you are developing commercially, you want to have a human on the other end of a phone call.

If it is a hobby, well, the weirder the better, I guess.

I was reading a bit on the ARM architecture the other evening, found this in a Wikipedia article. I thought, only 35,000? Wow! Contrast to 1.4B transistors in Intel's Ivy Bridge chips. Not exactly an apples-to-apples comparison, but the gap in performance is much less than the transistor counts might lead a person to believe.

Using the RISC approach, the core ARM processor requires only 35,000 transistors, compared to the millions in many conventional processor chips, resulting in lower power usage and making it very attractive in smaller devices.

I've often wondered about the ATtiny and ATmega chips, but have never seen a transistor count for them.

Looks like the LPC81xM chips are getting closer, Mouser now lists them as on order, although no delivery dates. Prices (single quantities) range from $0.78 for the LPC810 to $1.16 USD for the most expensive LPC812. Unfortunately the development board went up from $15.00 to $18.75 since I last checked. I may just order one up anyway. I also discovered that the free LPCXpresso IDE only does C, not C++. Major bummer.

I also discovered that the free LPCXpresso IDE only does C, not C++. Major bummer.

Yep, and restricted to 256k (or is it 128k?) code although that's seldom a problem.

To get C++ you have to buy the > 256k code size version for $256, major PITA and not a good way to entice people onto the platform I feel.


Rob

Yeah the free version is 128K, which as you say doesn't seem like much of a restriction. Then there are 256K and 512K versions, for $256 and $512 respectively. Cute. Obviously not a serious pricing policy, I wonder what they were thinking.

Graynomad:
My copy is long gone, that was in another life. Every time this comes up I say I'd like to make a retro Z80 board. One day.


Rob

If they made single-chip Z80 computers, how many would you buy?

I remember hearing that a single-chip 286 PC was done for military use before 1990, but no details. At the time I had an Amiga 1000 and a turboXT.

To get C++ you have to buy the > 256k code size version for $256, major PITA and not a good way to entice people onto the platform I feel.

No longer the case, the latest LPCXpresso free version supports C++.

If they made single-chip Z80 computers, how many would you buy?

Probably none, but I still like the idea of a retro board. Just started thinking about it (yet again) today.


Rob

Graynomad:
No longer the case, the latest LPCXpresso free version supports C++.

That's great news, thanks for the update, Rob!

Graynomad and Pico - I have the Z80 assembler, dissassembler and emulator working under Windows. Writtten in VB6. Now working on a set for the 65C02...

What i really want is a Z80, 64K of RAM and 8K of ROM (setup so the rom can be switched off and run totally in RAM) along with a serial port (or 2) all on one chip. Should be possible to put an entire CPM machine on a chip, with just the I/O necesary to hook op a Compact Flash for storage...

Hey, We all have our fantacies.

Z80, 64K of RAM and 8K of ROM (setup so the rom can be switched off and run totally in RAM) along with a serial port (or 2) all on one chip

No internal ROM/RAM but the HD64180 was close, MMU with bank switching and 2x UARTs.

Here's one in a board from the days when men were men, chips had legs and PCBs were the size of a serving platter not the wussy little credit-card sizes we have now.

http://www.80bus.co.uk/pages/gemini/images/GM880.jpg

I mean what use is a PCB if it can't double as a sand plate for your high-lift jack?

I used the 64180 years ago, very nice chip. Every 6 months or so I fantasise about building a retro board, it would be pretty easy. One day.

I have the Z80 assembler...Writtten in VB6.

Talking of retro.

I also have a VB6 program, started writing it 15 years ago and it's become quite an integral part of my photography DAM workflow. Trouble is it's getting harder to use VB6 stuff with every new version of Windows and I suspect you can't run it at all under W8. How are you going to deal with this? Any pointers?


Rob

So far I have been able to use it on XP and Win7, and run the programs on Win8. I hate the new versions of Visual Studio as it seems they went out of their way to break it and make it as slow as possible. Don't know exactly why they had to screw it up so bad when they went to .net, but VB in that environment is a totally different animal, and much slower to develop with.

Just today I was writing a couple of small programs, one on the survaillence computer at our transmitter, and one here at master control (tv station) to let the operator know when one of the cameras sees something. A total of less than 30 lines of code. Runs the program with the camera name on the command line and passes the that to a computer at the station which logs the event. Tomorrow I have to work on having it ring a bell...

Yes I think VB got too big and complex after 6, when it became part of the VS bloatware. VB6 with a few tweaks is all you need to make good Windows GUI programs. I have done some work with VS but life's too short for all that crap. There was a VB6 replacement that looked promising, the environment looked 100% the same and the code almost ported across without change IIRC. Can't remember what it was called now.


Rob

If they made single-chip Z80 computers, how many would you buy?

They do, you know. Zilog continued along and did microcontroller versions of the z80 with on-chip memory and peripherals.
It looks like the top-of-the-line runs single-cycle at 50MHz, has 256k flash, 8k ram, and various peripherals including ethernet.
Also, NEC did enhanced Z80 things, before becoming part of Renesas, and some of the Renesas CPUs are rather depressingly z80 like. Including the recently hyped RL78 series...