New hardware revision?

[simon]

Hi!

Brian from http://hackaday.com asked for a group buy. About 100 PCBs could be produced for those who are interested in building a Kiwi. I am not very convinced there is enough interest in a group buy yet. Any modern microcontroller system would be faster and cheaper.
Kiwi is a classic design intentionally. I started this project as I wanted to learn about 80ies computer architecture the "hard way". I think, exactly this is the strength of Kiwi: The study and design of such a system.
As I would have to rework the schematics as well as the PCB layout artwork to remove known issues, the overall design could be improved as well. A next generation Kiwi could have a MC68000 as CPU or DMA.

Now it is up to you. If there is a demand for such a project, feel free to participate. Maybe you want to contribute? You have ideas for hardware improvements? You want to program and supply software? Maybe you like to design a neat case for the PCB?

This forum wants to find out if there is enough interest in this project. If there is no feedback after a while, the project will be kept private.

Simon

[ChrisHale]

I think it would be a lot of fun. If the price isn't too prohibitive I'd be very interested in picking one up.

[florinc]

I would follow with interest. Keep up the great work!

[Altstar]

Hi Simon!

I'm in. Might be able to help with FPGA (Verilog) work, time permitting.

Have a great weekend!
Christoph

[d68]

Yes, i'm in. Very interesting project. I can do hardware and/or software design including pcb manufacturing. If cost< 150 euro I buy one.

Greetings from the Netherlands

[tsxownz]

hello

i came here following the post in hackaday. Being the 80s computer whore that i am... hehe... i am obliged to support this project.
i am interested on a revised version of this board.
However i think you should include a VGA port for using modern LCD's. Altough i admit that departs from the whole computing experience, CRTs these days are dying beasts.
Not to mention you can get a squarish 17" or 19" LCD for almost nothing.

let me know further news on this

thanks in advance
Ernesto

[simon]

Hello all and welcome,

I hope the forum doesn't need approval of postings any longer. Sorry for this!

For VGA there should be a scandoubler. The V9990 is capable to output a VGA signal, but it does this in two special office screen modes only. All the nice modes including the pattern modes are for standard PAL/NTSC scan rates. Does anyone know how a scan doubler works?

For a next PCB I will probably need supprt in designing a (very) clean power suppy. With this PCB I have slighty visible vertical lines. These are static. After a while running, when the power-suppy is warm, I recognize something like a ripple. Moving lines across the screen and a high frequent noise in the speakers. I wanted to insert a filter coil between the power-suppy and the PCB, but did test it yet.

Tomorrow I will try to write up all issues I am aware of.

Simon

[jonwil]

If I was going to enhance this design, I would replace the 68008 with a full 68000.
I would also replace the almost-impossible-to-get SID chips with something easier to get. Maybe you could use a Yamaha YM family sound synthesis chip and some sort of raw DAC chip to handle sound effects and percussion and the things that the YM cant really do.

Such a combo has been seen on all kinds of consoles and arcade boards and I bet the YM chips are easier to get than SIDs.

For display output, VGA would cover 80-90% of the computer monitors made in the last 20 years including many LCDs of all sorts and finding a suitable display that does VGA is easier than finding one that does composite output (that and VGA doesn't have the issues of PAL vs NTSC)

[netwar]

I am an avivd hacker and lover of retro tech and it would be awesome to buy a board.I have built my own foundry and if you need a prototype aluminum case/heatsink i could make 2-3 for you (I could manafacture for slightly larger scale for a small fee to pay for the fuel to run the furnace). I wish I could help with software but my job as a programmer eats my time like pac-man eats dots.
Just a nostalgic idea but maybe make a peripherial cassete interface haha. keep up the good work

[simon]

@jonwil: A MC68000 sound interesting. We should look, what changes would be needed. For now all chips are connected to addressbus line A1 upwards, which simplifies the change from software side. Then the 16 bit buffer can be dropped. But there has to be a second Eprom for a full 16 bit databus. What else?
BTW is a MC68030 that much harder to work with?
For sound... There is the SwinSID which claims to be a drop-in replacement for the SID. My actual design went with the SID as I prefer it's sound over OPL chips (I have a YM262 OPL-3 laying around) and the amount of SID tunes available (I am no musician). Some time ago I considered using the DOC chip. It is the soundchip of the Apple II/GS and it's developer is Bob Yannes who also developed the SID. But the DOC chip is very rare and a bus master by itself.

@netwar: Thank you! I have the same problem: Very limited spare time. This is why I want to change this into a comunity project. After a long time designing hardware I would prefer to program for a while now. So let's see, what can be done together. I will release the gEDA design files soon to proceed.
Sounds good. Do you have pictures of your foundry?

Simon