41–47 of 47 posts
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Let me self-promote my bitbox arm32 home-brewed console since it's somewhat on topic although less retro minded ( https://github.com/makapuf/bitbox/wiki ) edit : added link
That's a nice project. Ever think about adding an HDMI output? :)
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I'm just asking, why take that approach vs just building a Z80-based system to run CP/M?
OS-9 is a dramatically more capable OS than CP/M, in that it's a fully multitasking RTOS.
I broke mine on assembly. This is how I went about fixing it. https://feilipu.me/2016/06/08/rc2014-troubleshooting/
To reprogram the EEPROM, you need a programmer. This is one I use. https://feilipu.me/2016/06/08/tl866_testing/
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It's actually pretty surprising how much you can achieve with these 8 bit processors. My favourite example of pushing the 8 bit Arduino processor to the limit is this - 3D rendering at 320x240 x 16 bit: http://hackaday.com/2016/01/02/better-3d-graphics-on-the-ard...
That demo is rather impressive, but the AVR in an Arduino is much faster than a Z80. This machine is running at ~7.37MHz (which is fast compared to old Z80 based personal computers) whereas the Arduino typically runs at 16Mhz. Further, an instruction takes a minimum of 4 cycles on the Z80 and many take longer whereas most AVR instructions take only a single cycle.
The highest I've found that I can order is clocked at 20MHz [0]
[0] - http://www.digikey.com/product-search/en?mpart=Z84C0020VEG&v...
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It is fun: but I like this kind Bonzai tree thing which is not pactical but a relaxing but challenging experience. And it feel really nice to actually really understand everything for a change.
Any suggestions for something like that? I would love that feel too :-)
That said, it is a good start... If you can find a cheap one, find the schematic online and start checking out the components and measuring the signals. I am lucky to have many systems that have 74series logic + memory + cpu in them which is really easy to follow for any programmer. Most machines from that era won't have that unfortunately.
If you cannot or will not risk that then simply buy a power supply, some packs of analog electronics, digi scope (few $100 one is enough), a box (2nd hand you can get them cheap) of different 74series, breadboard and a computer kit like [0] or [1] or [2] and start experimenting.
[0] http://www.ebay.com/itm/Zilog-Z80-Colecovision-Kit-8MHz-Z80-...
[1] http://www.ebay.com/itm/Zilog-Z80-ZX-Spectrum-Homebrew-IC-Ki...
[2] http://www.ebay.com/itm/Mixed-Kit-6502-or-63C09-or-Z80-CPU-S...
My home-brew 68K machine just recently reached the same level of completeness except for the particular BASIC implementation (Tiny vs. Microsoft). Guess I should get it written up as a blog post or three.
Please do!
http://coderjames.bitbucket.org
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Please do!
I've started putting something together, but in case I never finish, I've at least tossed the schematics, gerbers, and CPLD source code up on the web, if you're really interested: http://coderjames.bitbucket.org Next I have to figure out how to properly make public the BitBucket repo holding the source code for programs that run on the system.