| wolfspraul | autorouters are overrated, I said it a few times :-) you should fully expect this kind of thing | 00:00 |
|---|---|---|
| wolfspraul | Apple again 'stunned' everybody by manually laying out the ARM cores in their latest-gen A6 chips | 00:00 |
| wolfspraul | so given tech industry history, in how many years does everyone else manually lay out their chips too? | 00:01 |
| wolfspraul | 2? 3? | 00:01 |
| azonenberg | wolfspraul: well they didnt manually lay out everything | 00:02 |
| wolfspraul | 'manual' is probably an overstatement, I would think they just use heavy instrumentation/guidance so that it comes out clean | 00:02 |
| azonenberg | and i wouldnt expect GREAT performance from an autorouter | 00:02 |
| azonenberg | But i'd expect mediocre rather than poor | 00:02 |
| wolfspraul | azonenberg: yes but you understand my point, the layout of apple's latest arm cores is very unusually 'clean' | 00:02 |
| azonenberg | Yes, and was probably done by hand | 00:02 |
| azonenberg | My point is, only the arm cores | 00:03 |
| azonenberg | not the whole doc | 00:03 |
| wolfspraul | maybe not worth it/not done yet | 00:03 |
| azonenberg | i'm going to say "not worth it" | 00:03 |
| wolfspraul | but you know autorouters... don't expect too much from them | 00:03 |
| wolfspraul | they can only do good if heavily guided | 00:03 |
| azonenberg | Yeah, I just expect its best guess to be better than garbage | 00:03 |
| wolfspraul | right, and to run! | 00:04 |
| azonenberg | i mean that doesnt even look like a local minima | 00:04 |
| wolfspraul | I think that's where >90% of people have more important things to do anyway, and what keeps the autorouters in play | 00:04 |
| wpwrak | azonenberg: maybe try to hand-optimize it. see if you can find a better local minimum. | 00:05 |
| azonenberg | wpwrak: i'm doing hand placement now | 00:05 |
| azonenberg | i was hoping i wouldnt need to do that because i wont be on the xc6slx45 for very long | 00:05 |
| wolfspraul | azonenberg on apple's heels | 00:05 |
| azonenberg | i just ran out of space on the lx25 and am moving to the xc7a100t as soon as i have time to finish designing this board | 00:05 |
| wolfspraul | can't be long until the lines are forming at his home... | 00:05 |
| azonenberg | i just jumped onto an atlys in the interim for a couple of months so my coding doesnt hit a standstill | 00:06 |
| wpwrak | well, i'm not overly surprised autorouters in fpgas aren't doing any better than autorouters on pcbs ;-) | 00:06 |
| azonenberg | Oh, i hand route all of my pcbs | 00:06 |
| azonenberg | But thats because they are somewhat less complex | 00:06 |
| azonenberg | i can afford to hand tune | 00:06 |
| azonenberg | on fpgas i cannot hand route everything | 00:06 |
| azonenberg | But hand tuning of autorouting is commonplace | 00:06 |
| wpwrak | i like my pcbs very small. that pretty much kills autoplacing and autorouting. | 00:07 |
| wolfspraul | http://www.semiwiki.com/forum/content/1676-hand-crafted-horsepower-apple-a6-soc.html | 00:07 |
| azonenberg | http://colossus.cs.rpi.edu/pictures/2012/October/10-5-2012%20-%20switch/S7302929.JPG | 00:07 |
| azonenberg | all hand routed | 00:07 |
| azonenberg | wow, it's been a month? | 00:07 |
| azonenberg | and i havent had time to assemble it yet | 00:07 |
| wpwrak | poor camera work but apparently good routing :) | 00:11 |
| azonenberg | lol my cheap camera cant handle low light well | 00:11 |
| azonenberg | i dont think skill could save it | 00:11 |
| wpwrak | tripod plus log exposure ? | 00:15 |
| azonenberg | long exposure... do you see how much thermal noise is on that sensor? | 00:15 |
| azonenberg | that isnt motion lbur | 00:15 |
| azonenberg | blur* | 00:15 |
| azonenberg | that's the sensor sucking | 00:16 |
| wpwrak | or flash. one useful trick is to use a bit of paper as a diffusor in front of the flash lamp. | 00:16 |
| azonenberg | I tried flash but i think it didnt turn out well | 00:16 |
| wpwrak | hmm, that much thermal noise is bad indeed ... | 00:16 |
| azonenberg | i mean its a long exposure but still | 00:16 |
| azonenberg | this is a $50 camera from three or four years ago | 00:17 |
| wpwrak | note sure how it affects long exposure, though. | 00:17 |
| azonenberg | what do you expect | 00:17 |
| azonenberg | It's irrelevant in short exposures | 00:17 |
| wpwrak | ah, okay ;-) | 00:17 |
| azonenberg | the SNR gets a lot better | 00:17 |
| wpwrak | one problem is that they increased resolution to ridiculous levels, while keeping the sensor size roughly constant. i think that has changed in the last years. | 00:18 |
| azonenberg | Yeah, this was a 3-megapixel sensor that was pretty small | 00:18 |
| wpwrak | 3 MP is still quite reasonable. | 00:20 |
| wpwrak | my camera has 10 MP :-( (canon sd880is) nice camera in general, but i'd be happier with half the resolution. | 00:21 |
| --- Sat Nov 3 2012 | 00:00 | |
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