#milkymist IRC log for Thursday, 2012-07-26

cladamwwpwrak, hi yes, the version of board-m1/r4/m1.pro we have in git is the same as mine locally.03:43
Action: xiangfu make the jtag detect slx9 success. with 10 wires connect. 6 jtag pins(Vref, GND, other 4 wires), one ACCINT, one ACCAUX, one GND, one VCCO_2.12:12
wolfspraulxiangfu: wow, congrats!12:28
xiangfuI broken one slx9 chip. maybe because 1. short pins?  2. too hot when I soldering it.12:29
wolfspraulright, either one12:29
wolfsprauldepending on how you do the manual soldering the heat is a big problem12:29
wolfspraulas a ballpark number you can say after 3-4 manual resolderings at most almost every chip will have some damage12:30
wolfsprauljust ballpark12:30
xiangfuI have one question about 'Chip Temperature Ranges', it says: 0°C to +85°C , but when we soldering the chip under SMT factory. the machine should be around ~200°C12:30
wolfspraulbecause you don't control the temperature exactly, how hot it is, how the heat spreads, etc.12:30
wolfspraulwell sure12:30
wolfspraulthat's what I'm saying, there are many subtleties with the heat12:31
xiangfu(manual soldering the heat is a big problem) yes.12:31
wolfspraul85 is a normal operating temperature still, I guess12:31
wolfspraulno shortening of average life expectancy etc.12:31
wolfspraulan smt reflow profile can be 245 or more degrees, 260, 26512:31
wolfspraulbut then it's exactly controlled how it's heating up there, how many seconds it stays there, how it's cooling down, etc.12:31
wolfsprauland a difference of 5 degrees may impact the yield a lot!12:32
wolfsprauleven 2 degrees, depending on chips etc.12:32
xiangfu~260. yes. but that machine don't damage the chip.12:32
wolfspraulheat is heat12:32
xiangfuok. I just saw your messages.12:32
wolfspraulno 'machine' will do anything to change physics12:32
wolfspraulbut with your manual iron, it's a mess12:32
wolfspraulit's more like throwing rocks at a glass installation12:33
wolfspraultotally not well controlled, bad heating up, bad cooling down12:33
wolfspraulit's a mess, so very stressful to the chip (in general)12:33
wolfspraulazonenberg seems to be quite successful with home-made 'reflow ovens' in the form of simple toaster ovens12:34
wolfspraulbut even that will take a lot of time to get working, and then you can improve more and more12:34
wolfspraulwith 10 usd chips, you are better off burning through some of them manually12:34
wolfspraulanyway those jtag news sound like a great first step!12:35
wolfspraulkeep that as a gold sample and make a 2nd board right away12:35
wolfspraulotherwise you risk going in circles and driving yourself mad :-)12:35
wolfspraulwhen soldering a whole chip, you can try to warm up the board and maybe chip on it a little with a hot air gun12:40
wolfspraulwarm it to 80-100 degrees, something like that12:40
xiangfugood idea.12:40
wolfspraulthat way the gap from there to the soldering temperature and back is not so abrupt12:40
wolfsprauland all parts can safely be operated at 80 degrees anyway, so that pre-warming will definitely not cause damage12:41
wolfspraulbut it reduces stress from sudden heat increase12:41
wolfspraulbut whatever you do, with a manual setup you cannot match a well controlled reflow oven and profile12:41
wolfspraulso think economical :-)12:42
wolfsprauldo you use leaded or lead-free solder?12:42
wolfspraulI think for manual soldering you can always just use leaded solder, no?12:42
wolfspraulthat makes it a lot easier12:42
xiangfuwhat is 'leaded solder'?12:42
wolfspraulhigh lead content12:43
wolfspraulnowadays all commercial mass-manufactured products try to be lead-free and use lead-free solder12:43
wolfspraulbut lead-free solder has a substantially higher melting temp12:43
wolfspraulyou can find more info on wikipedia12:43
wolfspraulyou probably use leaded solder...12:43
wolfsprauljust checking what could make your life easier12:44
xiangfu'lead-free' I just don't know this English word.12:44
xiangfuthere are 'solder' on the premade PCB.12:45
xiangfuI don't use any more solder. just heat up the PCB solder and PIN. then they are connect.12:45
xiangfubut I have to use 'liquid flux'.12:46
xiangfuwithout those 'liquid flux'. it just not working.12:46
wolfspraulmost likely that solder is leaded12:47
wolfspraulforget about lead vs. no-lead12:47
wolfspraulmaybe the air gun can help improve yield12:47
wolfspraulheat up pcb + chip before soldering12:47
wolfspraulbut not too much :-)12:47
wolfspraulmaybe pcb from bottom is best12:47
xiangfuand I have to use a different iron tip.12:52
xiangfuthe one that ship with SMD re-work station not working either.12:52
wolfsprauloh well12:53
wolfspraulgood that you quickly try others12:53
kristianpaulxiangfu: nice !14:35
kristianpaulo cara !14:40
kristianpauloi wpwrak :)14:40
wpwrakheya !14:42
xiangfuI saw the capacity write '50v 4,7uF'. so the MAX voltage is 50v, is there a minimal voltage for capacity?15:43
xiangfuI bought a bag of different capacity and resistor. but they are not for SMT. means very big. so in theory, they are should be same function on PCB. only different size and different composition.15:47
wpwrakxiangfu: no, there's no minimum voltage. it's safe to use them at 0.0 V ;-)15:49
xiangfuwpwrak, thanks. 0.0v :)15:50
xiangfuwpwrak, another question. I bought a AMS1117 , it's convert 5v to 1.2v. without this 4.7uF capacity, it give ~2.0v. after soldering a 4.7uF capacity. the voltage goes to 1.2v. why is that? (I am learning...)15:51
azonenbergwolfspraul: I use SAC305 lead-free and have no real problems with it17:22
mwallewpwrak: blubb :)20:08
mwalleanybody using a text based email client?20:40
wpwrakof course. mutt rulez !20:41
mwalledo you have some kind of kill thread feature?20:41
mwallewpwrak: do we need bits protection bits for user and kernel mode?20:51
kristianpaulmutt rule indeed :-)20:51
kristianpaulah thread..20:51
kristianpaulshift +d but it ask for a keyword, perhaps the thread keyword? :)20:52
kristianpaul^D                       delete-thread Hmm20:52
mwallekristianpaul: kill thread would move all furute message for that thread too20:53
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