How large is large for you? I use the 99SE autorouter for my "large" designs, but not for small designs. It takes a lot of practice and trial/error to figure out how to set up the autorouting rules for each board. And each board may take different rules. You just have to have patience. Typically I will spend a half day tweaking rules and testing them with trial routing runs. After you get an acceptable run, you will need to do some manual cleanup. Yes, it doesn't seem very productive. But it is still faster than routing the whole thing manually.
When I say "large", perhaps a better metric is "difficult". Our DOS Stamp is a 6-layer PCB with only 10 ICs on it, but it is very small (2.6 x 2 in.) and has SMT parts on both sides. Not a large design, but quite difficult given the small area and parts on both sides. The router does a good job on this board with the right rules. Another board I did recently was a PC/104 form factor 486-class custom SBC. 8 layers (2 power, 1 ground, 5 signal), 2 large PQFP208 devices and 12 other ICs. The router did a good job on it. An afternoon to tweak the rules, and 30 minutes to clean up afterwards. If you have lots of replicated circuitry with parallel, ordered busses, you can probably do better with manual routing. But if the circuitry lays out "randomly", as most of mine do, autorouting is a more productive choice. The pinouts of most of the chips and the placement of I/O connectors are constraints you cannot do anything about. If you have PLD/FPGAs, you can control the pinout of these devices somewhat. I tend to let the PLD/FPGA fitter do pin assigment, because I want the best utilization of chip resources. But the more large chips you have in your design, and the more vendors of chips, the more random your layout will be. Work with the router for a while. Everything in autorouter lore says it should be a "pushbutton" process. They don't say how many buttons you have to push to get good results! Also, keep in mind that an autorouter will never be as smart as you, only faster than you. Best regards, Ivan Baggett Bagotronix Inc. website: www.bagotronix.com ----- Original Message ----- From: "Tim Fifield" <[EMAIL PROTECTED]> To: "Protel EDA Form" <[EMAIL PROTECTED]> Sent: Friday, November 16, 2001 9:07 AM Subject: [PEDA] Autorouter > Just curious... Does anybody use the 99SE autorouter for large PCB designs? > Do the majority of board designers do everything manually? I don't even > bother with the autorouter anymore, it's to messy. Perhaps I'm not setting > it up properly. What do you people do? > > Tim Fifield > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
