#garfield Logs

Oct 21 2020

01:14 AM polprog: hi rue_mohr
01:21 AM polprog: good show!
03:01 AM polprog: ok, 2h break
08:07 AM polprog: phew
08:07 AM polprog: luckily we dont have ee labs yet
08:07 AM polprog: rue_mohr: what is the exact model of your minipro? TL866A or TL866II ?
08:51 AM rue_mohr: polprog, your code said to invert
08:51 AM rue_mohr: I tied the led from +5 (you didn't say) and it comes on when the button goes to ground
08:52 AM rue_mohr: so its 1:1, not inverted
08:52 AM rue_mohr: mine is a TL866II plus
08:52 AM polprog: hmm, there is one inversion in the code, and one in hardware
08:53 AM polprog: ok, so you have the newer programmer, good
08:53 AM polprog: anywya, it works!
08:56 AM rue_mohr: no
08:56 AM rue_mohr: when the input goes low, the output goes low
08:57 AM rue_mohr: as your code provided, does button down = low on
08:57 AM rue_mohr: but aside form that mystery, its good
08:57 AM rue_mohr: I'll do an OR gate, to find out if its the inputs or outputs that are inverted
10:08 AM polprog: weird..
10:09 AM polprog: maybe youre right, they are actually inverted
10:09 AM polprog: http://ee-classes.usc.edu/ee459/library/datasheets/16v8.pdf
10:09 AM polprog: im not sure what mode that equation makes
10:09 AM polprog: but i can see most modes have an inverted output. OK, youre right !
10:09 AM polprog: :D
10:28 AM rue_mohr: 98% I think the psych question got me
10:29 AM rue_mohr: ah, so output is inverted ok
10:30 AM rue_mohr: oo I like that datasheet
10:30 AM rue_mohr: oh damn, yea, looka that, a tiny little inverter on the output
10:30 AM rue_mohr: bastards
10:43 AM polprog: haha
10:43 AM polprog: what psych question?
10:44 AM rue_mohr: the rectifier is best decribed as - having a 3 phase input - outputs dc pulses
10:45 AM rue_mohr: uh
10:45 AM polprog: uhh
10:45 AM rue_mohr: it was amongst the context of single phase power, so I didn't go with 3 phase
10:45 AM rue_mohr: 8-|
10:45 AM rue_mohr: fun
10:46 AM rue_mohr: anyhow, I only got one wrong, I'm ok
10:46 AM polprog: good
10:46 AM rue_mohr: hows your schooling going?
10:46 AM polprog: im struggling with this mechanics question
10:46 AM polprog: im closer
10:47 AM rue_mohr: two body?
10:47 AM polprog: yeah
10:47 AM polprog: the exact problem is
10:48 AM polprog: i need to find the parabolic orbit of a point with a total energy of E
10:48 AM polprog: of E = 0
10:49 AM rue_mohr: lots of missing context
10:49 AM polprog: well, 3h of lectures of missing context
10:49 AM polprog: and probably somehting lost in transaltion
10:50 AM polprog: i need to find the r(t)
10:50 AM rue_mohr: if E=0 you have two counteracting fields
10:50 AM rue_mohr: if its a parabolic orbit, its 2d
10:50 AM polprog: yes
10:51 AM rue_mohr: so, two interacting fields, what are they shaped like?
10:51 AM polprog: in this case i have E = 0, that is the kinetic energy is the same as the field potential energy
10:51 AM rue_mohr: well, a potential field is just round
10:52 AM rue_mohr: the kinetic energy isn't
10:52 AM rue_mohr: is this solve-for-equation or solve-for-values
10:53 AM polprog: solve for equation
10:53 AM rue_mohr: Exy = E/r^2
10:54 AM rue_mohr: I dont know how to express the energy of the charged drop of oil :)
10:55 AM polprog: heh
10:55 AM rue_mohr: what has the kinetic energy?
10:56 AM polprog: a point mass
10:57 AM polprog: i know how to do it, i just need to transform what i got from the integral
10:58 AM Tom_L: hi peeps
10:59 AM rue_shop1: hey
11:00 AM rue_shop1: Tom_L, turns out, with polprogs datasheet, i can zoom in enough to see a not on the end of the output buffer in the GAL
11:00 AM polprog: what dadasheet did you have
11:00 AM polprog: data*
11:01 AM rue_shop1: its about 2 pixels wide in polprogs vector version at normal zoom
11:01 AM rue_shop1: ah OLD crookid scanned one
11:01 AM polprog: :/
11:01 AM polprog: link :D?
11:01 AM rue_shop1: oh not sure where I picked it up
11:01 AM rue_shop1: but thats the answer
11:01 AM rue_shop1: the fpga is probably the same thing
11:20 AM polprog: pk, this is getting good
11:20 AM polprog: i got a tangent function
11:22 AM aandrew: hm
11:22 AM aandrew: electronics question
11:23 AM aandrew: I have an IC with an output feeding a 10uF capacitor and that going to the + input of an LMV358
11:23 AM aandrew: that would essentially be 10s of MOhm on the right side
11:24 AM aandrew: what load impedance do I use to calculate the cutoff frequency?
11:26 AM rue_shop1: 358
11:26 AM rue_shop1: amp or regulator?
11:26 AM rue_shop1: oh that amp
11:27 AM rue_shop1: you mean the cap is series?
11:27 AM rue_shop1: aka
11:27 AM rue_shop1: audio ------||----------------> + input
11:27 AM rue_shop1: if the amp a comparator or an amp?
11:27 AM rue_shop1: like w/ feedback
11:34 AM aandrew: correct
11:35 AM aandrew: waveform gen -----||--- +in
11:36 AM rue_mohr: no other inputs on the +
11:36 AM rue_mohr: ...
11:37 AM rue_mohr: if there are no other inputs, then its null, your at the cutoff of the amp
11:37 AM rue_mohr: or you mean the low cutoff
11:37 AM rue_mohr: low?
11:38 AM rue_mohr: related:
11:38 AM rue_mohr: I grabbed a normal capacitor to use as a storage cap for a DS1307 lateley
11:39 AM rue_mohr: I only needed maybe 48 hours backup
11:39 AM rue_mohr: so I grabbed a 1000uF cap and gave it a try
11:39 AM rue_mohr: but the one I grabbed was scavanged, and it leaked down in a few minutes
11:39 AM rue_mohr: so, scavanged cap, whatever
11:40 AM rue_mohr: as I went thru all the caps in the shop, new or scavanged, I realized that the leakage on the average cap is kinda high
11:40 AM rue_mohr: and my 1M meter is a big load
11:40 AM Tom_L: caps are one of the crappiest electronics
11:40 AM rue_mohr: but even just letting it sit revealted it was dropping like crazy
11:41 AM rue_mohr: that said aandrew, I think the leakage will swamp out the input current of the amp
11:41 AM Tom_L: noisy, leaky, short, burn like hell if you lick the leads... the list goes on
11:41 AM rue_mohr: haha
11:41 AM rue_mohr: :)
11:43 AM rue_mohr: so, I learned that backup caps are low leakage
11:43 AM rue_mohr: but I went with a cr2032 anyhow
11:47 AM Tom_L: heh
11:53 AM rue_mohr: atleast I know the battery will work for a few years
11:53 AM rue_mohr: its about 10:00, next class isn't till 11:30
11:53 AM rue_mohr: "high voltage"
11:54 AM rue_mohr: I think thats 1200 and up
12:04 PM Tom_L: gonna be a lineman?
12:04 PM Tom_L: pays alot more
12:05 PM Tom_L: it's that whole risk/reward thing
12:29 PM rue_shop1: na
12:29 PM rue_shop1: I'll always be the obscure knowledge stuff guy
12:29 PM rue_shop1: fire alarms, plc's networking
12:33 PM polprog: same
12:34 PM polprog: hmm, i managed to work out.. the conic curve equation, and find the parameter
12:34 PM polprog: which is not what an answer is and im outta idea
12:34 PM polprog: s
12:34 PM polprog: do they keep default passwords for fire alarms in canada too :) ?
12:40 PM rue_shop1: conic
12:40 PM rue_shop1: thats 3d
12:41 PM rue_shop1: not usually worried about the passwords, I'm part of installing them before programming and doing yearly tests
12:50 PM aandrew: rue_mohr: sorry had to step out
12:50 PM aandrew: nothing else on the + input no just the cap
12:51 PM aandrew: but yeah I was thinking the same way - it's not actually filtering shit
01:06 PM aandrew: the input impedance of an opamp is essentially infinite
01:20 PM rue_mohr: well, its probably more than the leakage on the cap
03:37 PM polprog: nearly did the theory part of the question
03:37 PM polprog: i have my answer *just* like the excercise answer but the square root is different
03:37 PM polprog: :/
03:38 PM polprog: ill see what they answer
04:15 PM rue_shop1: hmm
04:15 PM rue_shop1: ok, my keybaord doesn't work on this 6502
07:00 PM rue_mohr: polprog, that is, of course, 0x42
07:00 PM rue_mohr: so not the meaning of life, the universe, and... wait a sec
07:00 PM polprog: of course :)
07:00 PM Tom_L: life has meaning???
07:00 PM polprog: 867-5309
07:01 PM rue_mohr: so not the meaning of life, the universe, and not the meaning of ... you got it
07:01 PM polprog: im getting up at 5:30... so see you on the flip side
07:01 PM rue_mohr: Tom_L, I got the keybaord working on this breadboarded 6502
07:01 PM polprog: i nearly got the phys problem solved
07:01 PM polprog: :
07:01 PM polprog: :)
07:01 PM Tom_L: i thought you said it didn't work
07:01 PM rue_mohr: upon reset, it prints "push button" and when you push a button is prints the value of the key in hex
07:01 PM rue_mohr: but its still got no ram
07:02 PM rue_mohr: I got it happening
07:02 PM rue_mohr: totally silly
07:03 PM rue_mohr: Tom_L, here is a video if you like
07:03 PM rue_mohr: https://twitter.com/RueNahcMohr/status/1319064944365584385
07:04 PM Tom_L: cool
07:04 PM rue_mohr: silly
07:04 PM rue_mohr: its keeping me warm anyhow
07:05 PM rue_mohr: _no_ ram...
07:05 PM rue_mohr: hahah
07:05 PM Tom_L: what's silly is all the wires it took to get to that point
07:05 PM rue_mohr: less to say the code is a little long, being no function calls
07:05 PM rue_mohr: yea I'm realizing why I am ok with serial busses
07:05 PM rue_mohr: the ram chip is like another 24 wires
07:06 PM Tom_L: you gonna run outta wire colors
07:06 PM Tom_L: what's even more ridiculous is it's on a breadboard with all those wires and it actually works
07:08 PM rue_mohr: oh just barely
07:08 PM rue_mohr: there have been a lot of fights
07:08 PM rue_mohr: *mash mash mash* reset, reset ...... ?
08:16 PM rue_mohr: debounce filtyers
09:00 PM rue_mohr: filename 7segtest1.tbl
09:00 PM rue_mohr: default 0x00FC
09:00 PM rue_mohr: memory ends at 0x0800
09:00 PM rue_mohr: Address | Data
09:00 PM rue_mohr: ------------------
09:00 PM rue_mohr: Priority | Qualifier | Modifier
09:00 PM rue_mohr: ---------------------------------------------------------
09:00 PM rue_mohr: 160 1 dF=0x71
09:00 PM rue_mohr: 150 1 dE=0x79
09:00 PM rue_mohr: 140 1 dD=0x5E
09:00 PM rue_mohr: 130 1 dC=0x58
09:00 PM rue_mohr: 120 1 dB=0x7C
09:00 PM rue_mohr: 110 1 dA=0x77
09:00 PM rue_mohr: 100 1 d9=0x6F
09:01 PM rue_mohr: 90 1 d8=0x7F
09:01 PM rue_mohr: 80 1 d7=0x27
09:01 PM rue_mohr: 70 1 d6=0x7D
09:01 PM rue_mohr: 60 1 d5=0x6D
09:01 PM rue_mohr: 50 1 d4=0x66
09:01 PM rue_mohr: 40 1 d3=0x4F
09:01 PM rue_mohr: 30 1 d2=0x5b
09:01 PM rue_mohr: 20 1 d1=0x06
09:01 PM rue_mohr: 10 1 d0=0x3F
09:01 PM rue_mohr: -1 1 lsn=A&0x0F
09:01 PM rue_mohr: -2 1 msn=(A&0xF0)>>4
09:01 PM rue_mohr: -3 1 seg=(A&0xF00)>>8
09:01 PM rue_mohr: -4 1 segbit=1<<seg
09:01 PM rue_mohr: > addrule
09:01 PM rue_mohr: ...
09:01 PM rue_mohr: so, I know what the two nibble values are
09:01 PM rue_mohr: I need to work out what value to use for each from the segment table
09:02 PM rue_mohr: if (lsn == 0) segsls=d0
09:02 PM rue_mohr: etc
09:02 PM rue_mohr: ok
09:02 PM rue_mohr: thanks
09:04 PM Tom_L: glad to participate
09:05 PM rue_mohr: I wrote this a long time ago, its been a while since I'v used it
09:05 PM rue_mohr: it uses rules to make memory maps
09:06 PM rue_mohr: it goes thru a list of rules
09:07 PM rue_mohr: seeing if the rule should be applied (qualifier) and otherwise applying it
09:07 PM rue_mohr: -5 lsn==0 segls=d0
09:07 PM rue_mohr: -6 lsn==1 segls=d1
09:07 PM rue_mohr: -7 lsn==2 segls=d2
09:07 PM rue_mohr: -8 lsn==3 segls=d3
09:07 PM rue_mohr: -9 lsn==4 segls=d4
09:07 PM rue_mohr: -10 lsn==5 segls=d5
09:07 PM rue_mohr: -11 lsn==6 segls=d6
09:07 PM rue_mohr: -12 lsn==7 segls=d7
09:07 PM rue_mohr: -13 lsn==8 segls=d8
09:07 PM rue_mohr: -14 lsn==9 segls=d9
09:07 PM rue_mohr: -15 lsn==10 segls=dA
09:07 PM rue_mohr: -16 lsn==11 segls=dB
09:07 PM rue_mohr: -17 lsn==12 segls=dC
09:07 PM rue_mohr: -18 lsn==13 segls=dD
09:07 PM rue_mohr: -19 lsn==14 segls=dE
09:07 PM rue_mohr: -20 lsn==15 segls=dF
09:07 PM rue_mohr: these ones assign segls (segments, least significant) to the value holding the font bits
09:08 PM rue_mohr: now I have to repeat for segms
09:11 PM rue_mohr: this is the most complex thing I'v ever done with it
09:14 PM rue_mohr: ok... that ... should do it...
09:16 PM rue_mohr: hahah oof, thats work for it
09:16 PM rue_mohr: there are like 50 rules for each memory loc
09:16 PM rue_mohr: uh
09:16 PM rue_mohr: not this long... wtf
09:19 PM rue_mohr: Address 2046:
09:19 PM rue_mohr: Applying rule 160: q:1 m:dF=0x71
09:19 PM rue_mohr: Applying rule 150: q:1 m:dE=0x79
09:19 PM rue_mohr: Applying rule 140: q:1 m:dD=0x5E
09:19 PM rue_mohr: Applying rule 130: q:1 m:dC=0x58
09:19 PM rue_mohr: Applying rule 120: q:1 m:dB=0x7C
09:19 PM rue_mohr: Applying rule 110: q:1 m:dA=0x77
09:19 PM rue_mohr: Applying rule 100: q:1 m:d9=0x6F
09:19 PM rue_mohr: Applying rule 90: q:1 m:d8=0x7F
09:19 PM rue_mohr: Applying rule 80: q:1 m:d7=0x27
09:19 PM rue_mohr: Applying rule 70: q:1 m:d6=0x7D
09:19 PM rue_mohr: Applying rule 60: q:1 m:d5=0x6D
09:19 PM rue_mohr: Applying rule 50: q:1 m:d4=0x66
09:19 PM rue_mohr: Applying rule 40: q:1 m:d3=0x4F
09:19 PM rue_mohr: Applying rule 30: q:1 m:d2=0x5b
09:19 PM rue_mohr: Applying rule 20: q:1 m:d1=0x06
09:19 PM rue_mohr: Applying rule 10: q:1 m:d0=0x3F
09:19 PM rue_mohr: Resulting value: 252
09:20 PM rue_mohr: o
09:20 PM rue_mohr: Applying rule -200: q:segls&segbit m:D|=1
09:21 PM rue_mohr: its stuck trying to evaluate the qualifier somehow
09:24 PM rue_mohr: Applying rule -200: q:(segls&segbit)!=0 m:D|=1
09:24 PM rue_mohr: oddd
09:24 PM rue_mohr: why is it getting stuck...
09:58 PM rue_mohr: oooh
09:58 PM rue_mohr: It cant do |= yes
09:58 PM rue_mohr: yet
10:03 PM rue_mohr: it did it
10:04 PM rue_mohr: I aparently need to implement |=
10:04 PM rue_mohr: I thought the table would look... more.... random...