frazzled routing dense boards

.....

I have to say that for dense boards I now use Electra, which on the whole,

is very good and EXTREMELY fast.

However, Electra is not completely bug free - is anything? I just found one

annoying one with mixed power/signal layers which, although not producing

errors, resulted in suboptimal optimisation. However, their support is good

and they fix stuff when its broken.

Eagle's autorouter is good, but very slow and single threaded - on the

boards I'm working on at the moment, I estimate that Eagle is at least 15 -

20 times slower than Electra, and possibly a lot more - both are running on

the same host using XP Pro with 4Gb RAM.

Nick

David Pollum wrote:

Using both EAGLE v4.16r2 and v5.2, I have routed relatively simple 2 and

4 layer boards, using mostly digital logic chips and CPLDs.  I used both

through-hole and SMD parts.  And except for bypass caps, all parts are

mounted on the top (layer 1).  I've gotten pretty good at doing these

low density digital boards.

 

However, I recently routed a small 4 layer analog/digital board (EAGLE

v5.2) that has dozens of components on each side.  This board was far

more dense than any boards that I had done before.  With both the top

and bottom layers active (1 & 16), plus a spaghetti bowel of airwires, I

had some problems positioning the parts and routing the board, and I

became quite frustrated with myself and sometimes with EAGLE.  Sometimes

it hard to know if an airwire is connected to a pad, or if it's merely

passing over a pad.  I'm hoping that someone has a better, less

frustrating approach or strategy to dense board design, and who would

willing to share some tricks of the trade.

Thanks!

 

-Dave Pollum

 

I might be over simplifying your situation but here goes; I usually turn

off airwires while I am placing my parts. I come up with a placement

strategy based on the schematic, which I notate. With printed and

notated schematic in hand (looking at it on paper is much nicer), I

place the parts with no regards to the airwires. I then turn on airwires

and start routing my critical signals...

I absolutely have to move the parts around in the routing process, but I

find that it gets me a good start at things.

Tony

Anthony Rolando wrote:

David Pollum wrote:

 

Using both EAGLE v4.16r2 and v5.2, I have routed relatively simple 2

and 4 layer boards, using mostly digital logic chips and CPLDs.  I

used both through-hole and SMD parts.  And except for bypass caps, all

parts are mounted on the top (layer 1).  I've gotten pretty good at

doing these low density digital boards.

 

However, I recently routed a small 4 layer analog/digital board (EAGLE

v5.2) that has dozens of components on each side.  This board was far

more dense than any boards that I had done before.  With both the top

and bottom layers active (1 & 16), plus a spaghetti bowel of airwires,

I had some problems positioning the parts and routing the board, and I

became quite frustrated with myself and sometimes with EAGLE. 

Sometimes it hard to know if an airwire is connected to a pad, or if

it's merely passing over a pad.  I'm hoping that someone has a better,

less frustrating approach or strategy to dense board design, and who

would willing to share some tricks of the trade.

Thanks!

 

-Dave Pollum

 

 

I might be over simplifying your situation but here goes; I usually turn

off airwires while I am placing my parts. I come up with a placement

strategy based on the schematic, which I notate. With printed and

notated schematic in hand (looking at it on paper is much nicer), I

place the parts with no regards to the airwires. I then turn on airwires

and start routing my critical signals...

I absolutely have to move the parts around in the routing process, but I

find that it gets me a good start at things.

 

Tony

Tony;

Good tips, thanks.

-Dave Pollum