PDM has the lowest output ripple if you are making a DAC, but if switching power, the switching frequency can get pretty high
(switching loss issue)
worst case is 50% duty cycle
it spends one period high, one low
I think everyone so far has used it as a pseudodac
well no that's not true
for instance me
no, you're switching power with it
must be ok at low power
not much power, but...
hmm, it turns out that dithered PWM is really just a special case of PDM
so, instead of an int param to select the type of modulation, its gonne be a bit
should it default to PWM or PDM
I think pdm
so the bit param would be something like "pwm.0.pure-pwm"
default value 0
it looks like there will also be a insmod param
0 = a single output, duty cycle ranges from 0 to 1
1 = two outputs, duty cycle ranges from -1 to 1, output is PWM and DIR
2 = two outputs, duty cycle ranges from -1 to 1, output is UP and DOWN
that sounds good to me. I think I'd use type 1 for etch servo
I'm not sure which type cradek will be using, because he doesn't use "enable"
type 2, I suppose
dat's why we have choices
2 is what freqgen makes today
that reminds me, the component should have an enable pin
except I hacked in "count" which is like PWM without DIR
maybe it should be hacked back out, I dunno
I'm inclined to say yes, hack it back out (at least once the pwmgen component is done
I wonder, should I call it pwmgen, or just plain pwm?
"pwmgen" -> consistent with existing "generator" components
yeah, I'm leaning that way too
I started to call it pwm, but its not too late to change
would single out be 50% duty cycle for no movement?
depends on how you hook it up
I personally would _not_ use single out for an axis control that wants to move both ways (H-bridge)
its more appropriate for some single ended function
ah - was only thinking axis movement. Single minded
non-reversing spindle speed or something like that
a quick question
EMC2 uses nmllib
we'll see how quick the answer is ;)
what is the difference with rcslib
RCSLIB is multiplatform, PD, etc
works on doze, solaris, linux, etc
but libnml is not?
libnml is basicly RCSLIB stripped to work only on linux
libnml is LGPL
is it developed by NIST?
RCSLIB was developed by NIST
libnml is the clean'n'mean implementation of RCSLIB by Paul Corner
that was to quote him
alright, thanks a lot again!
it's basicly the same stuff reorganized a bit, and beautified to be able to read better, etc
losing all the #ifdef hell in there
EvertL: no problem ;)
hi jeff.. what's up?
oh not much
* alex_joni ponders about trying 6.06
I tried the "live" 6.06 for a short time
I think it's the same.. isn't it?
I didn't see anything that made me too exciting
CD I mean..
yeah, the primary CD is "live"
I looked at it a bit .. can't find the udebs anymore..
means more trouble to figure it out :/
yeah I'm sure
although I noticed there's a new 'alternate CD'
which is something for OEM installs, and other custom deployments
yet.. no documentation on it afaik
I was a bit disappointed by the "live" CD. There's not a clear shortcut for "put some persistent data on my USB key" (or hard drive or whatever)
instead you have to follow some instructions from the wiki which involve things like creating partitions and filesystems, and give a boot parameter each time you start the live CD
so it's just a gimmick, really
that sounds bad
but then again.. people probably only want to look at it once..
not to actually keep running it as a Live CD
booting it on the laptop right now..
jepler: what do you usually use to see available WLAN's ?
alex_joni: umm, I thought it was "iwlist ap" but that doesn't actually seem to work
cradek_ is now known as cradek
jepler: I tried a few combinations.. but it doesn't seem to be working :/
what's up ray?
Bought a business with a couple partners.
specialized wood products.
My contributions will be automation of some of the production lines.
hmm.. seems it might even work:
changed breezy with dapper in my sources.list
sudo apt-get update
sudo apt-get dist-upgrade
1042 upgraded, 195 newly installed, 46 to remove and 0 not upgraded.
Need to get 569MB of archives.
wah that's a bit much for my phone line.
wonder how much is already on the 6.06 CD
I saw they were giving out disks. I'll have to order some.\
How soon do you think EMC2 will be ready for it.
we need to see how appropiate it is first
it's a new kernel on it
rayh: someone has to compile, package, and test a new realtime kernel
rayh: I think you can use the breezy emc2 packages & kernel on dapper
Ah yes. The kernel build thing. I promised myself about a year ago i wouldn't do that again.
I can understand why
it doesn't really want to take the stuff from the CD
up to package #750 downloaded
I alex - how is the dapper live?
Hi alex - how is the dapper drake live
pretty ok, nothing breathtaking though
I see little difference from 5.10
they mostly worked on the server cd
I have the iso burned - but I doubt I will do any thing with it for a while.
but, as we speak I am running sudo apt-get dist-upgrade
to see if it works :)
good luck :)\
seems it finished..
back in a reboot :D (if it still works)
dapper is here :)
so you upgraded your 5.__?
yeap, it's 6.06 now
does emc work?
but emc2 won't run :)
cradek: some issue with rtai
it put in a new kernel I'm sure
no, same kernel
juve@ubuntu:~$ uname -a
Linux ubuntu 2.6.12-magma #1 Sun Feb 19 12:23:11 CST 2006 i686 GNU/Linux
what error? I bet it's udev
can't wite to /dev/rtai_shm
yup, I plan to reinstall emc2
check for /etc/udev.something/emc2
might be easier for users
sudo apt-get install --reinstall emc2
yeah if that fixes it
hmm.. there is no /dev/rtai_shm
the /etc/udev/rules.d/emc2.rules is there
but I see that all other rules are using numbers before
/dev/rtai_shm is only created when rtai is loaded
actually it's /dev/RTAI_SHM
the udev rule causes a symlink
it's not beeing created
which the RTAI_SHM or the symlink?
I see the modules get inserted, but in the end scripts/realtime start complains that it can't write to /dev/rtai_shm
Module Size Used by
hal_lib 28172 0
rtapi 25792 1 hal_lib
rtai_math 25860 0
rtai_sem 14976 1 rtapi
rtai_shm 8192 1 rtapi
I see rtai_shm is loaded
hmm.. the testsuit is failing aswell
juve@ubuntu:/usr/realtime-2.6.12-magma/testsuite/kern/latency$ sudo ./run
Error opening /dev/rtf/3
well that has always failed
rtai has very crappy support for udev
ok then :)
yes you have to mknod yourself to run the test
didn't you figure out a way to make the /dev/rtf/N at boot time?
yes but it sucked so I took it out when I found enough udev to make emc run
who wants to see a screenshot of AXIS & emc2 running on dapper ? :-) ( http://dsplabs.cs.utt.ro/~juve/emc2-dapper1.png
what's the fix?
hang on.. that isn't working
I just did : sudo mknod -m 666 /dev/rtai_shm c 10 254
easy to remember
that's great until you reboot
I wanted to see if it works at all..
looking at the udev stuff now
ah I see
do you have your stick?
the one you poked udev with..
sorry I lost it
I see an links.conf.dpkg-bak
with the RTAI stuff in it..
what is links.conf?
thought you'll know..
oh maybe that's the way I did the first time, but quit using
that's not the right fix
is that the one that chides you at the top of the file for even looking at it?
this file does not exist..
ok, what's the proper fix then ?
something to do with udev...
sorry I really don't know
wonder what they changed to break it
no, I meant what was your fix?
on breezy rtai creates /dev/RTAI_SHM
now it sounds like it doesn't
all i did was tell udev to make a symlink rtai_shm -> RTAI_SHM so emc was happy
that's what the magic in /etc/udev/whatever/emc2.rules does
oh, right.. the emc2.rules
is the RTAI_SHM always there?
or only when the stai_shm module gets inserted?
udev creates it when it gets inserted
root@ubuntu:/etc/udev/rules.d# insmod /usr/realtime-2.6.12-magma/modules/rtai_shm.ko
root@ubuntu:/etc/udev/rules.d# ll /dev/rtai_shm
crw-rw-rw- 1 root root 10, 254 2006-06-02 23:33 /dev/rtai_shm
ok, got the fix.. :)
can you put it into the rtai package?
is it easy?
root@ubuntu:/etc/udev/rules.d# cat rtai.rules
might be emc.rules or whatever :)
I wonder if that harms breezy
don't think so.. but you probably will try before :D
can you send the fix to me in email please
oh, duh.. I haven't deleted the node
it was still there from the mknod I did earlier ..
is anybody here?
I adjusted Jon's picture on EMC's modularity, made it al little simpler and put HAL in there
By simpler I basically mean I only use the parts I think I understand
I would appreciate it if somebody could take a look at it?
URL is http://evertlammerts.nl/emc2structure.bmp
only one thing..
the TASK doesn't talk NML to the motion controller
it's exchange of NML-like messages through a shared memeory
I noticed that. That is staically defined in the code isn't it?
Basically they use the same headers and make pointers to the structs in shared memory, if I understood well
staically = statically
Is there any plan to use NML for it?
something like that
no, NML presumes some c++ code, which isn't likely to be happy in the kernel
and this is faster
Alright, I see. thanks again!
hmm.. it seems the move from 5.10 to 6.06 wasn't that successfull after all
early in the boot phase I get an oops
which results in some parts to not be loaded
like the sound subsystem..
I'm surprised it did run ..
yeah.. one of those ;)
* jepler wonders how long he should "seed" ubuntu 6 in his bittorrent client
it did strike me as odd that it booted in about 10 seconds
* alex_joni wonders how it worked
is that only when you use the rtai kernel from breezy, or all the time?
I think all the time..
but I'm about finished with the 6.06 installer
btw.. ircing form it :)
while it installs? that's cool.
it is :)
it starts as a live cd
yeah I booted it for a short time to look at it
and you have a shortcut on the desktop to install
but I didn't realize that meant you could keep using it while it installed
I ran firefox & other stuff
you can even continue using the live cd after the install is finished :D
or restart.. like I'm about to ..
seems that worked rather well
now the emc2 install :)
* jepler burns his second dapper cd, the first one having become unreadable despite booting fine a few times before.
cradek: I wonder why lilo gets suggested during the emc2 install
dang.. finished installing emc2 & chris's kernel
but it doesn't work :(
it simply stops during boot ..
started out promicing :)
skunkworks: guess we'll need a new kernel based on 2.6.15 afterall