The schematics...

This is the schematic for the CPU board of my TinkerBug 6809 computer. It is basically the board that Frank Wilson designed and that was published in The Computer Journal way back when. I have modified it slightly and added the 74LS138 circuit to allow me to select up to 8 I/O devices. Otherwise it is pretty much Frank's design. I re-wrote the monitor code to suit my needs. I kept the bit-banging code to drive the PIA as a serial port.

This is an idea I have for a backplane PCB. It's not the one I'm using now although the basic circuit is very similar. The power connector (J1 & J2) is wired up to work with an old AT-style PC power supply.


Here is the schematic for the ATA/IDE board I am working on. It is still a work in progress and this circuit may change if the need comes up.

This is the circuit for the Floppy Controller board I use. It is from an old Swedish publication and has its share of errors. Those errors cost me many hours of troubleshooting before I got the thing to work properly. I am in the process of re-drawing this so once I have that done I will post it here.

Still in a holding pattern

Well, I'm still in a holding pattern waiting on the parts for the ATA/IDE board. I have gotten confirmation that they have been shipped but I don't have any tracking information so all I can do is wait.

I have started wire wrapping the ATA/IDE board using what I have so far so things are moving forward slowly.

I have re-drawn the schematics for the CPU and FDC boards using the free edition of Eagle CAD so I will post them up here soon.

In a holding pattern

Ok, so not much progress on the hardware front for this project. I am still waiting on several of the components I need for the ATA/IDE board. The place I ordered them from is reasonably priced but they aren't very fast.

I have been fiddling a bit with a PL/9 compiler but am having some problems with it. Mainly, it seems to have a problem with the non-echoing input routine I have in my monitor. FLEX and everything else is working fine with it though so at this point I'm not sure what is going on. When I have some more time I may try and do some deeper debugging of it.

I did get a new MicroATX power supply for the case I'm working on so now I have all four floppy drives installed. Now I have two 3.5 inch and two 5.25 inch  drives to play with.

Next up: an ATA/IDE Interface

This is the beginning of the ATA/IDE interface board. I borrowed the design from here and had to modify it slightly to work with the bus of the 6809 CPU. I'm still waiting on several of the components and parts so I haven't been able to do much with it yet.

Rather than trying to patch FLEX to use LBA I think I'm just going to stick with CHS sector addressing for now. It will still give me about 16MB of harddisk (or 41 diskettes) so it will be plenty. At least to start with. The CHS method could be done so the drive looks like a really large diskette to FLEX.

Computer setup of yesteryear!

This picture shows the now almost finished computer system. The case is still a work in progress. It needs a MicroATX power supply (the one I inherited with the case was dead), a modified front and then a fresh coat of paint. I have a spray can of gloss black ready and waiting.

This picture shows that I am in the process of formatting diskettes. I have found a couple of 3.5 inch drives that I am using now so I am able to format 80 double sided tracks. That gives me about 395KB of space on each. Yes, that is KiloBytes.

My next project, which is waiting on some parts that have been ordered, is to attempt to attach an ATA/IDE harddisk to the system. More to come about that.