#garfield Logs

Oct 23 2020

03:56 AM polprog: rue_mohr, hint
04:10 AM polprog: rue_mohr: https://polprog.net/rozne1/ircjunk/computers/amidiag.jpg :-) 8 displays, 8 PALs
08:20 AM rue_bed: 8 pals! awefull
01:38 PM polprog: one pal per display :v
01:39 PM polprog: i bet it could be done with 1 pal for the decoder and a couple buffers
01:39 PM polprog: tristate buffers*
01:39 PM polprog: but i think it was supposed to show the adddress bus state without any delays/changes
01:40 PM polprog: so you cant have the segments scanned, that could give you false readings
04:27 PM rue_mohr: pff
04:27 PM rue_mohr: delay, strobe at a few hundred hz and you cant see any finer changes anyhow
04:27 PM rue_mohr: but honestly, the buffers take up lots of room too
04:27 PM rue_mohr: cheaper tho
04:27 PM rue_mohr: must have been new out of school
04:28 PM rue_mohr: if I'v learned one thing with that tek scope, its "practical limits"
04:28 PM rue_mohr: AND that resistor box was an eye opener
04:29 PM rue_mohr: even 1% values are WAY off
04:29 PM rue_mohr: some resistors they dont even try to make, they just pull other values that fall in the range
04:36 PM polprog: i mean, if you were strobing it it could happen that the addresses change with the strobe frequency and you get false readings
04:36 PM polprog: but that card sems to be rare, so originally it must have been hella expensive
04:36 PM rue_mohr: and if your going thru at 200hz, nobody can see the difference
04:36 PM rue_mohr: yea
04:36 PM polprog: what i mean
04:37 PM polprog: imagine your address changes the same frequency as the display
04:37 PM rue_mohr: heh, aliasing
04:37 PM polprog: so you might get the first nibble of address 1, 2nd nibble of address 2 and so on
04:37 PM polprog: never displaying a true address
04:37 PM rue_mohr: it brings up a method of solving the problem
04:37 PM polprog: yeah buffers
04:38 PM rue_mohr: if you take 3x 8 bit input shift registers, a t13, and two 8 bit output shift registers
04:38 PM rue_mohr: for 6 digits
04:38 PM rue_mohr: (24 bits)
04:39 PM rue_mohr: I think there is a huge charlieplex solution, but the duty would be really low
04:39 PM rue_mohr: unless you pull tricks that would make your brain hurt
04:40 PM rue_mohr: even then, the issue is pin count
04:40 PM rue_mohr: needing 24 input pins is brutal
04:40 PM rue_mohr: I think it balances best with a 128k ROM that handles 3 digits with a 4017 doing the digit strobe
04:41 PM polprog: hmm
04:41 PM polprog: maybe ill have less stuff next week to play with your rom
04:42 PM polprog: how are the GALs going?
04:42 PM rue_mohr: a 6 digit setup would be: 1 2803 driver (with 1 gate being an oscillator) a 2003 driver, a 4017 and 2 128k roms
04:42 PM rue_mohr: well I didn't go past that basic test
04:42 PM rue_mohr: I only have that 1 gal
04:42 PM rue_mohr: everything else is palce
04:42 PM polprog: ahh
04:43 PM rue_mohr: which supposedly have a custom protocol thats liscenced
04:43 PM polprog: yeah...
04:43 PM rue_mohr: bastards
04:43 PM rue_mohr: I'll try one anyhow
04:43 PM rue_mohr: later
04:43 PM polprog: it wont program i think
04:43 PM polprog: i mean
04:43 PM rue_mohr: yea
04:43 PM polprog: it will think it programmed but will fail the verify
04:43 PM rue_mohr: someone must have cracked it
04:44 PM rue_mohr: I mean, a few seconds with a logic ana and you got it
04:44 PM Tom_L: you need a secret decoder ring for it
04:46 PM polprog: ive gotta check out the software for these HC12 mcus
04:46 PM rue_mohr: oh I might have all the official stuff
04:46 PM rue_mohr: I think 12 was up from 16
04:46 PM polprog: i found some suite on a http file mirror
04:46 PM polprog: but i dont remember...
04:46 PM rue_mohr: no wait I did hc11, and the stuff I had was for hc16
04:46 PM polprog: the name
04:47 PM rue_mohr: wonder what 12 is
04:47 PM polprog: the other desk is a mess anyway
04:47 PM polprog: id have to clean it, wake everyone up
04:47 PM polprog: 68hcs12
04:47 PM rue_mohr: yea
04:48 PM rue_mohr: ooh its the dip28 with the uv window?
04:48 PM polprog: no, its a qfp with a zillion pins
04:48 PM polprog: oh the soft i found is "cypress codewarrior"
04:48 PM Tom_L: hc11?
04:48 PM polprog: 12
04:48 PM Tom_L: as in 68hc11?
04:49 PM polprog: yes
04:49 PM Tom_L: mmm i got some of those
04:49 PM rue_mohr: 12 or 11?
04:49 PM Tom_L: still got an unassembled kit
04:49 PM Tom_L: 11
04:49 PM Tom_L: one with external ram
04:49 PM rue_mohr: yea well he has a 12
04:49 PM Tom_L: well pfft i got a 68332
04:49 PM rue_mohr: we used hc12 in school
04:49 PM polprog: https://polprog.net/rozne1/ircjunk/various/devbrds.jpg
04:49 PM polprog: bottom left
04:50 PM polprog: aandrew sent them to me
04:50 PM rue_mohr: "learning assembler" I was borred on that one
04:50 PM polprog: rite of passage. i still have to check the syntx for x86
04:50 PM rue_mohr: oh god its huge
04:50 PM polprog: for some reason i stuck to att syntax
04:50 PM rue_mohr: oh I hate trying to work out which way things go
04:50 PM polprog: that blackfin board is interesting
04:51 PM polprog: hmm, netbsd supports blackfin
04:51 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/lightseeker/lightseeker2.jpg
04:51 PM polprog: linux dropped support
04:51 PM Tom_L: 11
04:51 PM polprog: huge
04:51 PM polprog: :)
04:51 PM Tom_L: heh
04:51 PM Tom_L: for what it did yeah
04:52 PM polprog: let me guess, two comparisons and a busy loop :v
04:52 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/maxbot/image023.jpg
04:52 PM Tom_L: 68331
04:52 PM Tom_L: 683323
04:52 PM Tom_L: shit
04:52 PM Tom_L: 68332
04:52 PM rue_mohr: so polprog what do you have tasked for the hc12?
04:52 PM polprog: hacking around
04:52 PM polprog: make a led blink
04:52 PM polprog: learn
04:53 PM rue_mohr: heh, k
04:53 PM polprog: get a feeling ;)
04:53 PM Tom_L: the 12 had some power didn't it?
04:53 PM Tom_L: i never got one
04:53 PM rue_mohr: 16 bit
04:53 PM polprog: what were these pics taken with?
04:53 PM polprog: and the old pics on your site rue?
04:53 PM Tom_L: yeah those are pretty old
04:53 PM rue_mohr: my _OLD_ pics are webcam
04:53 PM rue_mohr: iirc I called it the crapcam
04:53 PM Tom_L: nikon but scaled way down
04:54 PM polprog: not poking fun, i just find it curious as they have a very peculiar look
04:54 PM rue_mohr: my new pics are via 10MP camera, but I scale 'em down
04:54 PM polprog: imaging device wise
04:54 PM polprog: mine are phone or either camera
04:54 PM rue_mohr: if you give me a number I can shoot you a full size orig
04:54 PM Tom_L: all my late ones are phone
04:55 PM polprog: 338_avrstation :P
04:57 PM rue_mohr: polprog, you know the 40 pin chip in a semi-old keybaord?
04:57 PM polprog: yeah i recall
04:57 PM rue_mohr: 8748 equiv
04:57 PM rue_mohr: they are OTP
04:57 PM polprog: mcs48?
04:57 PM rue_mohr: but they ahve a 'use external memory' pin
04:58 PM polprog: hmm
04:58 PM rue_mohr: pin 7
04:58 PM rue_mohr: EA
04:59 PM rue_mohr: ya put it high
04:59 PM polprog: i can guess :)
04:59 PM polprog: now i need to find it
04:59 PM rue_mohr: I been collecting them for ages waiting for a simple task for them
04:59 PM rue_mohr: apparently 7 segment decoding isn't it, but
05:00 PM rue_mohr: the programmer got me thinking
05:07 PM Tom_L: U 2 and your vintage chips :)
05:08 PM polprog: its fun
05:08 PM polprog: these old chips are all different
05:09 PM Tom_L: yeah
05:10 PM polprog: so my cat has found himself comfortable sitting on my laps when i sit on the computer chair
05:10 PM polprog: he never did that before
05:10 PM polprog: maybe im sitting away enough from the desk
05:11 PM polprog: 00:10
05:11 PM polprog: hmm, i shoud catch up on the lectures
05:20 PM rue_shop1: something seems odd
05:20 PM rue_shop1: 128k?
05:20 PM rue_shop1: should be 12+2 address lines
05:20 PM rue_shop1: 14
05:21 PM rue_shop1: yea 128 goes to A13
05:21 PM rue_shop1: which is 14 lines
05:21 PM rue_shop1: huh
05:21 PM rue_shop1: these HP displays are awesome tho
05:21 PM rue_shop1: its just all in htere
05:22 PM rue_shop1: did you hear the comment? these are $10 ea!
05:22 PM polprog: yup
05:22 PM rue_shop1: I'll hook 6 up to the 6502 with the single step
05:22 PM rue_shop1: that will be entertaining for a bit
05:22 PM polprog: blinkenlights
05:23 PM rue_shop1: hmm
05:23 PM rue_shop1: I suppose its really not much more is it
05:23 PM polprog: its something cool innit
05:23 PM rue_shop1: I'd like to make a tiny little programmable board tho
05:23 PM rue_shop1: soemting with a lcd and kb you can enter a small program and run
05:24 PM polprog: i shoudl see if i can hack the z188 PCB i have
05:24 PM rue_shop1: I had proposed another one with an 8031
05:24 PM polprog: lemme find a picture
05:24 PM rue_shop1: is it a payment terminal
05:24 PM rue_shop1: that had a vfd?
05:24 PM polprog: i recall one
05:24 PM rue_shop1: and a magnetic card swipe?
05:25 PM polprog: early if not first verifone
05:25 PM rue_shop1: hmm
05:33 PM polprog: https://polprog.net/rozne1/ircjunk/various/z80disp.jpg
05:33 PM polprog: https://polprog.net/rozne1/ircjunk/various/z80disp2.jpg
05:34 PM polprog: these are siemens made PD3537
05:35 PM polprog: board runs on 5V, has a sram, keyboard/display cntrl and its missing the rom
05:35 PM polprog: in theory, i burn a rom with z80180 code, slap it in it works
05:35 PM polprog: the display controller probably runs the 7 segment ones and the modules are directly on the address bus
05:39 PM polprog: goodnight
06:01 PM polprog: gah, watching the lectures instead
06:01 PM polprog: i wrote a function in emacs lisp today
06:01 PM polprog: that puts incldue guards inside the file
07:25 PM rue_mohr: wholy crap!
07:25 PM rue_mohr: 8279 hahah
07:25 PM rue_mohr: thats an evil useless chip
07:27 PM rue_mohr: I'd like to know if you got the answer to that problem
07:32 PM MoonyMoon: hay rue_mohr !
07:35 PM rue_shop1: hey
08:37 PM rue_mohr: ok I did it, the hex displays were on the 6502
08:37 PM rue_mohr: are
08:44 PM rue_mohr: funny thing, it doesn't single step the writes
11:38 PM rue_shop1: iiinteresting, avr thresholds are symetric for a 3V supply