G1-ATA Devices

[OzOnE]

Thought I'd add the schematics here too...

http://oi58.tinypic.com/l8g0k.jpg

http://oi60.tinypic.com/zxpc14.jpg


It's a very simple design - basically most of the IDE signals between the three connectors (DC / GD / IDE port) are connected together apart from the /Reset signals and the CDDA clocks...

The idea was to make a flexible design that could be useful for connecting to an FPGA board (for GD EMU experiments and data capture).

It breaks out the CDDA signals onto the jumper pins, as these are not normally carried on a standard IDE connector.
This lets us use an external board for CDDA playback emulation (if it proves difficult to do in software).

Also, it routes the CDDA Clock signals to the jumper pins so you can either get the CDDA Clock from the GD drive (as normal), or input an external clock, or use an on-board oscillator module for if we can ever do a true "GD Drive free" BIOS patch.


Basically, for normal use with an IDE device set to Slave, you'd plug the GD drive on top of the G1 adapter, connect all the /Reset signals together (so the DC can Reset both the GD drive and IDE device), and connect the GD CDDA Clock to the DC CDDA Clock input (using a jumper).

It makes more sense when you see the schematics.

No point trying to protect the "design", as it's so simple.

If anyone would like to get a new batch of boards made up, please remember that there are a few known issues with this current design...

I only used three pins for the /Reset signals, so you can't just fit two jumpers side-by-side.
It will need two "/G_RST" pins (/Reset FROM the DC) next to each-other to fix this.

The board ended up being slightly too big to fit it against the plastic part of the modem / LAN housing when in the DC case.

The IDE connector was "mirrored" wrong on the PCB layout, so it's actually the wrong way around.
(I had to pull the plastic shroud part off the 40-pin IDE header, and rotate it 180-degrees. lol)

This is also why the IDE connector is on the underside of the adapter, but I think it actually works quite well like that because it supports the board from bending down.

Also, the positioning of the jumper pins and power connections are not be optimal.
(You'll notice that the jumper pins had to be bent downwards so they don't short out when the GD drive is placed on top.)

This is pretty much the best I could do at the time, but the PCB layout needs much improvement.

The power connections are important, as they allow you to easily connect to a CF / SD adapter or small 2.5" laptop HDD using a "floppy drive".

The GD drive on top unfortunately means that it will sit about an inch higher than normal too, so the DC case won't fit back on.
The shorter Molex connector for the top part is apparently no longer available.

This issue may be fixed if we can do a proper BIOS patch or a small CPLD board so the DC no longer searches for the GD drive.

So, quite a few things to think about and fix.

OzOnE
P.S. @SWAT, megavolt85, and others - Thanks for your work, and for the post on the Blog.