#emc | Logs for 2008-12-03

[01:39:11] <skunkworks> skunkworks is now known as skunkworks__
[01:40:55] <skunkworks__> skunkworks__ is now known as skunkworks___
[02:40:00] <jepler> huh, this is an odd way to modulate a signal: http://www.picbasic.co.uk/forum/showthread.php?p=45597
[02:48:09] <JymmmEMC> jepler: It makes perfect sense for LED's and such.
[02:48:30] <JymmmEMC> I'd suspect that it would save battery life too
[03:45:07] <renesis> jymmmemc: doubt it, switching is wasted power during slew
[03:45:16] <renesis> that looks like way more switching per period
[03:45:43] <renesis> like, real full cycle periods, not like they define them
[03:46:39] <renesis> 100Hz period with two switch slews (standard low speed led pwm) is def way more efficient in that sense
[03:47:23] <renesis> With 8-bit PWM, you would have to Interrupt 256 times per cycle to accommodate multiple outputs switching at different times.
[03:47:26] <renesis> And at 100 Hz refresh rate, it would need 25,600 interrupts per second.
[03:47:58] <renesis> um, on your avg uC you would allocate a pwm peripheral and youd only interact with it to change duty
[03:49:23] <renesis> also 25000 KHz isnt a very fast int rate if youre already doing a timered main loop
[03:50:54] <renesis> since led cycling period isnt essential, you can likely integrated into your faster timered mainloop, and do as many pwm out ports as you want in most situations just tracking a count reg and comparing against pwm duty values
[03:51:06] <renesis> * renesis done led on uc alot =
[03:54:56] <SWPadnos> the power advantage in that scheme is that the CPU only has to be running for 8 interrupts/second instead of 256 (all this is assuming that there's no hardware PWM)
[03:55:04] <SWPadnos> err - per period that is
[03:55:44] <renesis> im pretty sure it kills you resolution too
[03:55:49] <renesis> not sure tho
[03:56:17] <SWPadnos> nope
[03:56:27] <renesis> in any case that didnt occure to me
[03:56:36] <SWPadnos> it just uses the bit weights to get proportional time slices
[03:56:46] <renesis> because running enough leds to make it valueable, that much power saved wouldnt make a huge diff
[03:56:49] <SWPadnos> also, you can just shift the duty cycle out the port bit
[03:56:55] <SWPadnos> heh
[03:57:09] <SWPadnos> there is that - the LED probably uses 10x the power of the uC
[03:57:44] <renesis> depends on the uC alot
[03:58:10] <SWPadnos> you're right - maybe the LED is 100x the CPU (for one LED)
[03:58:12] <renesis> avr i dont think gets under half a mA in sleep mode
[03:58:29] <renesis> like special conditions you maybe get lower
[03:58:53] <renesis> running lower speeds at lower voltages, but now youre having issues just interfacing the leds
[03:58:56] <SWPadnos> in sleep it should be well under 1mA unless you're using a >40 pin mega
[03:59:17] <renesis> so now youre losing power in voltage conversion cercuits
[03:59:24] <renesis> not much, but some
[03:59:47] <renesis> i dount well under .5mA tho
[04:00:03] <renesis> theres alot of variables w/ running peripherals
[04:00:04] <SWPadnos> oh - I may be thinking of power-down mode
[04:00:09] <SWPadnos> sure
[04:00:21] <renesis> well i just mean the low power mode
[04:00:24] <SWPadnos> WDT, clocks, edge interrupts all add to it
[04:00:29] <renesis> fuck if i remember which mode was called which
[04:00:34] <SWPadnos> yeah, me either
[04:00:53] <jepler> typical power consumption, active mode, 1MHz, 1.8V: 230uA -- attiny2313 datasheet
[04:01:00] <renesis> yeh
[04:01:07] <jepler> I assume that's exclusive of power for I/O
[04:01:08] <renesis> who the fuck uses them at 1MHz 1.8V
[04:01:13] <renesis> has to be
[04:01:54] <renesis> itll hold state in powerdown so you can be full shutdown and sinking 10mA off a pin
[04:02:04] <jepler> 11mA for 20MHz, 5V
[04:02:09] <renesis> yeh
[04:02:16] <renesis> i think they had graphs
[04:02:20] <jepler> yep
[04:02:35] <renesis> but yeh in any more realistic mode its like around 1-5mA
[04:02:49] <renesis> and running them full speed its almost not even worth it
[04:03:04] <jepler> depends -- in a device that's not battery operated, why not
[04:03:22] <jepler> in a device that's battery operated, well, maybe you'll be interested in the power consumption at 32kHz...
[04:03:43] <renesis> i think you can actively throttle 2313
[04:03:50] <renesis> maybe just hit the /8
[04:04:19] <renesis> but im pretty sure some of the parts you can modify main clock
[04:05:11] <renesis> so yeah, throttle down, load timer with adjusted value for wakeup if its not event based, shut down
[04:05:12] <jepler> the 2313 has a system clock prescaler from /1 to /256
[04:05:17] <jepler> the tiny2313 that is
[04:05:20] <renesis> in the fuses
[04:05:35] <renesis> can you adjust from the prom code?
[04:05:47] <jepler> yes, you can program CKDIV8 in the fuse
[04:05:49] <renesis> im pretty sure there was something you could do in realtime
[04:06:00] <jepler> but you can also change the scale at runtime
[04:06:04] <renesis> oh sexy
[04:06:16] <renesis> is that ll of them or just 2313?
[04:06:28] <jepler> I'm only looking at the 2313 datasheet
[04:06:32] <jepler> I can't look at them all at once :-P
[04:06:34] <renesis> i think it exceptional in that respect but i havent even thought about this shit in forever
[04:06:36] <renesis> ha
[04:07:06] <renesis> i cant even program on
[04:07:14] <renesis> new pc doesnt have serial or parport
[04:07:22] <renesis> and my dragon is esd fucked
[04:07:41] <renesis> i have a usb to serial thinger but i cant find my rs232 cable =(
[04:07:58] <jepler> pick up arduino or make a board based on something from the at90usb series -- both program nicely over usb
[04:08:01] <SWPadnos> digikey: AVRISP2
[04:08:01] <jepler> fast too
[04:08:07] <SWPadnos> $25 or $30
[04:08:36] <SWPadnos> oh, $34 now. bummer
[04:09:20] <jepler> speaking of at90usb, the at90usb162 has an interesting clocking feature: it can switch from the external oscillator to the internal calibrated RC at runtime
[04:09:38] <jepler> (I think this is to help the device get close to the USB requirement for consumption in powerdown, though according to the errata they didn't make it:-P)
[04:09:47] <SWPadnos> useful for devices that may get plugged/unplugged from USB ports
[04:10:17] <jepler> erratum: rd Release
[04:10:17] <jepler> High current consumption in sleep mode
[04:10:17] <SWPadnos> oh - if by external oscillator you mean that it can clock from USB :)
[04:10:37] <jepler> Problem fix/workaround
[04:10:37] <jepler> USB waiver allows bus powered devices to consume up to 2.5mA in suspend state.
[04:10:48] <jepler> SWPadnos: no, that's not it
[04:11:21] <jepler> you have to have a nice high quality multiple-of-1MHz clock on board to generate the required clock for USB data from some internal PLL
[04:11:54] <jepler> but USB requires a suspend mode with x00uA current draw, which your 3.3V, 1MHz AVR is not likely to hit
[04:12:11] <jepler> hence the switch to a slow RC oscillator during USB suspend
[04:12:38] <SWPadnos> ah, ok
[04:13:00] <SWPadnos> so you swap between the 32khz (or whatever) and the real clock depending on power state
[04:13:08] <jepler> oops, past my bedtime -- goodnight all
[04:13:15] <jepler> SWPadnos: right
[04:13:20] <SWPadnos> see you
[04:13:38] <seb_kuzminsky> goodnight jepler
[10:56:52] <piasdom> g'mornin all
[14:52:06] <skunkworks_> another 4 inches of snow today.. It is offically winter
[14:53:31] <archivist> was frosty Monday and the battery needed charging to start the car
[14:54:08] <alex_joni> looks like 64F tomorrow here
[14:54:31] <alex_joni> only 55 today
[14:54:57] <archivist> 61f indoors here
[14:55:28] <skunkworks_> :)
[14:55:52] <skunkworks_> hey the java update this morning fixed the displaying of the smiley faces here.
[14:56:37] <skunkworks_> 27deg here today
[14:56:53] <skunkworks_> * skunkworks_ keeps the house at 60deg
[14:59:00] <jepler> not much snow here, but all the roads are covered in ice
[14:59:04] <jepler> nasty driving conditions
[15:01:21] <toastatwork> sixty degrees holy jesus
[15:06:13] <cradek> as long as I don't sit still long, the shop is fine at 55
[15:06:46] <alex_joni> hmm.. that's a bit too cold for me ;)
[15:07:04] <archivist> I fed up with being cold
[15:07:23] <alex_joni> archivist: move sto somewhere over here :)
[15:07:27] <alex_joni> *to
[15:07:49] <archivist> cheaper living probably
[15:08:26] <alex_joni> yeah, probably
[15:08:37] <alex_joni> lots more headaches though
[15:24:47] <alex_joni> hmm.. google reader is really nice
[15:36:54] <jymm> archivist: Yeah, vampire bats and such
[16:08:22] <alex_joni> s/bats//
[16:10:56] <jymm> alex_joni: Well, I was trying to keep the village from panicing
[16:11:25] <jymm> alex_joni: Don't wanna see too many CNC pitchforks ya know
[16:14:16] <jymm> alex_joni: But a bunch of a CNC Holy-Water cannons would be very cool!!!
[16:33:55] <alex_joni> garlic + slingshot ftw
[16:35:53] <alex_joni> this sounds like fun btw: http://en.wikipedia.org/wiki/Slingshot_paintball
[16:48:12] <boKono> Hello. I kindly want to ask about end-switches for a 3-axis cnc mill. Can emc2 run an automated homing with all 3 switches in series or parallel (depending if they are NO or NC ?
[16:51:05] <boKono> nobody here?
[16:51:20] <archivist> yes plenty IRC is not instant
[16:51:54] <boKono> :D Sorry.
[16:52:35] <boKono> Which version of ISO would you take for a VIA C7 CPU?
[16:53:37] <boKono> I see that there's a new one based on Ubuntu 8.x, but this CPU is a bit weak with its 1GHz.
[16:54:31] <archivist> 1 ghz should be ok, depends what latency you get
[16:54:36] <alex_joni> boKono: try the 6.06 first
[16:54:46] <alex_joni> if it's ok, then there's no need for 8.04
[16:55:03] <alex_joni> if you have some driver issues, then try 8.04 (should be ok performance wise too)
[16:55:11] <boKono> Oh, that's not really the problem. I want to build a little CNC mill, I don't have to win a race...
[16:55:21] <alex_joni> regarding the switches: you can set it up the way you need it
[16:55:38] <alex_joni> either series or parallel, and you can home them automatically (just not at once)
[16:55:58] <alex_joni> you use a command (home-all) and they'll home one by one
[16:56:04] <archivist> boKono, I have 606 on an 800 meg athlon and 8.04 on a P4
[16:56:37] <alex_joni> boKono: where from?
[16:56:41] <boKono> So I cannot click "home" and the mill homes automatically, first Z, then X, then Y, as an example?
[16:56:48] <alex_joni> yes you can
[16:56:58] <boKono> I am from Austria.
[16:57:19] <boKono> And you?
[16:57:23] <alex_joni> one click, and it will home Z first, then X, then y (if you like that order)
[16:57:29] <alex_joni> a bit more to the east
[16:57:33] <alex_joni> romania
[16:57:41] <boKono> Ah!
[16:57:45] <alex_joni> quite an assorted crowd in here
[16:57:52] <alex_joni> boKono: far from wien?
[16:57:58] <SWPadnos> quite a sordid crowd too
[16:58:13] <boKono> No. I am almost in its centre. :)
[16:58:29] <alex_joni> boKono: there's a company just outside (in moedling) that uses emc2 on small mills
[16:58:43] <boKono> Really? What is its name?
[16:58:50] <alex_joni> www.thecooltool.com iirc
[16:59:03] <boKono> never heared from.
[16:59:22] <alex_joni> villeicht ist ein kleines metalline von denen ja genug :) (weiss ja net was du vor hast)
[16:59:36] <boKono> Aha, deutsch!
[17:00:46] <boKono> Ich habe eine kaputte Graviermaschine gekauft (Elektrokik ist durchgebrannt gewesen), aber die Mechanik ist 1A. Ich will damit Kunststoff bearbeiten.
[17:00:49] <alex_joni> boKono: it's best to keep it in english in here (most people understand that better than german)
[17:01:08] <boKono> Ok, back to english..
[17:01:32] <alex_joni> do you have motors already?
[17:02:35] <boKono> Steppers and mechanics is OK. I also built new drivers, but I cannot supply more than 0.7A. Though that should be enough, I want to use only very fine tools.
[17:02:59] <alex_joni> ok, sounds good
[17:03:15] <boKono> I only have no time. :/
[17:03:17] <alex_joni> 0.7A might be a bit weak, but there's always possible to up that later :)
[17:03:29] <boKono> Have the mill since ~ 1 year...
[17:03:46] <alex_joni> it's eather time or money that is short usually
[17:03:49] <archivist> I use 2.4A on my steppers
[17:04:40] <boKono> So you have a really high torque then. :)
[17:04:58] <archivist> no not that high
[17:05:07] <alex_joni> depends on the size of the machine
[17:05:13] <boKono> sure.
[17:06:13] <alex_joni> boKono: are you familiar with IRC/private messages?
[17:07:22] <boKono> I found out that the chipset of this little computer (VIA CN700 graphics) is not well supported (graphics). Which ubuntu should I try first?
[17:07:52] <boKono> alex_joni: why you ask?
[17:07:59] <alex_joni> I sent you a message
[17:08:18] <boKono> Didn't see it... moment.
[17:08:25] <alex_joni> boKono: you probably end up using the vesa driver on both ubuntu versions, so it shouldn't matter
[20:38:51] <skunkworks_> so - is yahoo down?
[20:39:11] <skunkworks_> or is it just me?
[20:39:54] <skunkworks_> it pings
[20:42:29] <pjm_> yahoo.com is working here
[20:42:58] <skunkworks_> odd
[20:44:45] <skunkworks_> ok - working here now
[22:38:48] <dmess> hi all