#garfield Logs

Jul 22 2023

04:12 AM polprog: rue_shop3: https://mastodon.social/@whitequark/110755679414409091
04:25 AM polprog: the STM32 DMA peripheral can write to its own registers, so you can make a state machine out of five DMA channels that keeps toggling a GPIO indefinitely (or do other things, e.g. set a DAC or a timer) by repeatedly reconfiguring itself back and forth
04:25 AM polprog: without any CPU involvement
09:30 AM Tom_L: morning
10:58 AM rue_mohr: polprog, !!!
10:59 AM rue_mohr: why couldn't I do that with an 8237?
11:00 AM rue_mohr: 4 channels...
11:22 AM polprog: rue_mohr: maybe you were close
11:23 AM polprog: though i wonder if you could bootstrap an 8237 into running itself..
11:23 AM polprog: which sounds like a nut to crack for compiler theorists
11:23 AM polprog: i reckon you would need to write a compiler for it. Or have a small ROM that would initialize it and then it could go on inside the RAM
11:47 AM rue_mohr: yea, beent here
11:47 AM rue_mohr: yea, been there
11:47 AM rue_mohr: but yea, I dont know if it can write to itself
11:47 AM rue_mohr: might be why I figured it would require 2 chips
11:50 AM rue_mohr: wait, that was just posted 13 hrs ago?
11:50 AM rue_mohr: I talked about mine like a year ago
11:50 AM polprog: yeah, but i thought it might interest you
11:51 AM polprog: whitequark sometimes posts these shower thoughts into the void
11:52 AM rue_mohr: I wonder if there was any inspiration from my comments about it....
11:52 AM rue_mohr: huh
09:54 PM rue_mohr: ok, I changed the drivers side window runners in the trucj
09:54 PM rue_mohr: WOW it was involved
09:55 PM rue_mohr: you have to take the window out
09:55 PM rue_mohr: I still dont know quite how its done
09:55 PM rue_mohr: pulled it off somehow
11:02 PM rue_mohr: when I went to clean the window I noticed there are scratches all over it, I dont know if that just happened or if I only just noticed because I cleaned it
11:02 PM Tom_L: yep those can be a pita
11:02 PM rue_mohr: the process went quite well and I'm pretty sure I didn't just scratch it
11:03 PM Tom_L: if the weather seal was wore out that would do it
11:03 PM rue_mohr: some of the scratches are crosswise tho
11:03 PM rue_mohr: thats what I replaced that whole felt weather strip and wiper strips
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1290025.jpg
11:04 PM rue_mohr: http://ruemohr.org/~ircjunk/tempimage/p1290028.jpg
11:04 PM Tom_L: the horizontal scratches could be from driving with it partway down
11:05 PM Tom_L: vibrating on the weather seal
11:05 PM rue_mohr: its a long one tho, with a turn at the end (one of them)
11:05 PM rue_mohr: the window fell out of the track ages ago and I fixed it
11:05 PM Tom_L: who knows then
11:05 PM rue_mohr: its the kinda scratch you would expect from that lifter arm
11:06 PM Tom_L: i had a painted topper on mine as well
11:06 PM rue_mohr: I dunno, with the spackle of red paint, its not close to a perfect window anyhow
11:06 PM rue_mohr: topper? like a rain hood?
11:07 PM Tom_L: bed topper
11:07 PM rue_mohr: ah
11:07 PM rue_mohr: the canopy is nice
11:07 PM Tom_L: mine had side windows that opened as well as the rear glass
11:07 PM rue_mohr: I want to redo the astroturf on the bed, but the kids these days dont know what astroturf even is
11:08 PM Tom_L: have it sprayed with rhino liner
11:08 PM Tom_L: maybe too old a truck to afford that
11:08 PM rue_mohr: yea, without the thing I normally have in there its getting scratched up quick
11:08 PM Tom_L: both my kids did that
11:08 PM rue_mohr: well, the bumper is scaling right thru
11:08 PM Tom_L: that stuff is pretty tough but on my s10 i put a thick rubber mat in the bed
11:08 PM rue_mohr: there are some non-minor chunks of metal missing
11:09 PM rue_mohr: yea, a rubber one would be ok with me too
11:09 PM Tom_L: i liked it
11:09 PM Tom_L: like 1/4" or so thick
11:10 PM rue_mohr: I guess if the box goes, it becomes a flatbed
11:10 PM Tom_L: or find another one to put on it
11:10 PM rue_mohr: well, the scale on the frame is doing its thing too
11:10 PM rue_mohr: so, the clock is ticking
11:10 PM Tom_L: for red, it's not that faded out
11:11 PM rue_mohr: cause a new frame is out of any budget that exists
11:11 PM rue_mohr: it was repainted before I bought it
11:11 PM Tom_L: oh
11:11 PM rue_mohr: yea
11:11 PM rue_mohr: not a super awesome paint job either
11:11 PM rue_mohr: just a for-sale dressup
11:12 PM rue_mohr: I'm not sure how long it will last
11:12 PM rue_mohr: pretty sure everything will go at once tho
11:12 PM Tom_L: longer than mine :)
11:12 PM rue_mohr: there is a clutch in the transmission I keep attention of
11:13 PM rue_mohr: 1st->2nd
11:13 PM Tom_L: i had over 200k miles on it when the kid bought it
11:13 PM rue_mohr: so 2nd
11:13 PM rue_mohr: this one passed 333k km a bit ago
11:14 PM rue_mohr: 333k km is ~207k miles
11:14 PM Tom_L: i wanted to say closer to 300k but wasn't sure
11:14 PM Tom_L: well into 200 though
11:15 PM rue_mohr: its been super low on km
11:15 PM rue_mohr: cause I was only driving it about 20km/week for like 15 years
11:16 PM rue_mohr: we salt the roads in winter here, so its hard corrosion for cars
11:16 PM Tom_L: yep
11:16 PM Tom_L: they mostly use brine here
11:16 PM Tom_L: at least on the faster roads
11:16 PM Tom_L: streets may get sand or rocksalt sand combination
11:16 PM rue_mohr: so, the inductive charger pad I got from china arrived
11:17 PM rue_mohr: I have the charger pad, a charger sticker for a phone, and a li-ion charger it plugs into
11:17 PM rue_mohr: the idea is an inductive charging station for the floor sweeper bots
11:17 PM rue_mohr: BUT
11:17 PM rue_mohr: you have to kinda tight hug the pad to get it to go
11:18 PM Tom_L: her car has one for phones
11:18 PM rue_mohr: so, I'm wondering if I should have the bots drive up to it on the wall instead of the idea of them parking on it
11:18 PM rue_mohr: supposedly good for 5w
11:18 PM Tom_L: definitely not fast chargers
11:19 PM rue_mohr: thats fast for one of these
11:19 PM Tom_L: i suppose
11:19 PM rue_mohr: 3.7V 1Ah
11:19 PM rue_mohr: (800mAh to 1.2Ah)
11:21 PM Tom_L: do they convert AC to DC on those to get them to work?
11:21 PM rue_mohr: high fre
11:21 PM rue_mohr: high freq
11:21 PM rue_mohr: like 1Mhz or so
11:22 PM rue_mohr: then the pickup is just a loop of wire
11:25 PM Tom_L: wonder what frequency inductive heaters are
11:25 PM Tom_L: i know they're rather effective
11:31 PM rue_mohr: in 2001 I scoffed at the idea saying there was no way to really get descent power thru them
11:31 PM rue_mohr: but wa surpirsed to get enough thru the coupling on a hard drive to light up an LED
11:32 PM Tom_L: all the tooling at my kid's work use induction heated holders instead of collets
11:34 PM Tom_L: which is what most shops have gone to here
11:52 PM rue_mohr: mhm
11:52 PM rue_mohr: so he can send me all the old R8 tooling?
11:52 PM rue_mohr: :D