I've been using my lunch hours for quite some time now trying to figure out a compact routing for an ATAPI to IDE (laptop) adapter and I think I've got one albeit with some questions still attached.
I used the CD-ROM pinouts from Toshiba and the IDE pinouts from SciElectronics FAQ along with BigDog's spreadsheet identifying the pin to pin arrangement. The first issue that I have is that the pinout from Toshiba's site specifies which pins are "digital ground" vs "ground" and neither of the other sources identifies digital ground. So.…I arbitrarily separated out ground pins for digital, does it really matter.
I laid out the traces using the guidelines from apcircuits with .008 inch minimums for both trace and spaces. That doesn't address the issue of power. I found this calculator for trace width requirements based on how much power the trace will carry but I haven't found any information on power requirements for the individual pins to/from a laptop CD-ROM. So again I arbitrarily fattened up the power and ground traces to .016 inches.
When laying out the VIA's I couldn't find any guidelines for how much of a (for lack of a better term) flange I should leave at the ends of the VIA's for soldering purposes etc. How small is the bottom edge of practical?
I couldn't figure out what to do with the four pins off the ATAPI connector for the sound, so I routed them to a 4-pin header (2mm spacing). If that was the right thing to do with them it really needs a smaller connector and I've struck out in that department as well, any suggestions on a smaller connector would be appreciated.
BTW: the links to free samples of the ATAPI connector (click on the sales link) and the Header are listed in this boards Free Sample thread. (OK the header isn't listed but I'll put it there soon, and yes I did get a free sample of the ATAPI connector….not that I can solder that tiny stuff yet)
The biggest issue is getting it produced, I hadn't found any way past the $1500 to $2000 set-up fees the pop out of the fine print at every prototype board shop I can found until r-fl-z suggested I take another look at expresspcb.com. I did and as long as I'm willing to forgo the green protective layer and silkscreen I would end up with about 30 (10 per board X 3 boards) of these adapters (without the soldered on components). I do not have any interest in trying to produce and re-sell these things. However, if anyone is interested in going in on this with me to justify one run please drop me an e-mail. Also if any one is interested in taking this over for what ever reason (Codeman, Badflash; are you guys reading this) please drop me an e-mail.
I'm converting this board over to the expresspcb software (the original was e-mailed to a few people in pdf format for comment) and in looking the board over I can now see a way to re-route a couple lines and add one via so as to get access to 3 ground pins on the IDE header that I did not connect to the ATAPI pads, but I don't see it as necessary. If I've made an error in that assumption please speak up.