OT: topic (2023 Update)

Not many people actually do electronic design, and the ones who do are reluctant to show what they are doing in any detail.

So they feed the lunatic fringe instead?

The trolls are killing interest in this group, and the group is helping them by responding to - The Marching Morons.

John :-#(#

OK, post some interesting electronics, preferably something specific. A few real EEs show up here occasionally and might have something intelligent to say.

But yes, the less on-topic and the more stupid the thread, the longer it is.

I don't do what most of you folks consider that interesting electronics. Most of my work is trying to save obsolete games using 1970s 8-bit CPUs. I design a few boards, have a friend or two make others that are deeper in FPGA than I can go (no time or skill), but I try to have some fun with it all.

For example, one problem I am looking for a solution is trying to read old single CHIP CPUs such as the Signetics/Philips MAB84XX series of chips. I know the ROM is embedded in the chip and can't normally be gotten at, I'm thinking thought that there is a rare document floating around that would show how to verify the ROM/RAM code by sending some signal in the T (est) pin-Input pin, testable using the JT1 or JNT1 instructions, whatever those are! Not covered in any documents I've found so far though. I've found these so far which aren't bad:

Other 8-bit MPUs had such tests so you could cycle the data out to make sure the chip is good, why not this one?

Like I say, fun, but not very modern tech...

John :-#)#

That's interesting to me, for one.

Cheers

Phil Hobbs

Here's a thing, it's a type of Cuk converter. If you just replace the top FET with the PMOS to avoid a high-side driver, and try to run it with no dead time it's ugly, the body diodes face the wrong way to allow the two FETs to switch off simultaneously gracefully and the diode & LC network rings and rings.

Cross coupling a bit of feedback from the inductors to the FET gates seems to clean it up. 5 volts to about -135 with a more reasonable 85% duty cycle than the 95%+ a boost would need, the efficiency of a boost with that high a ratio would probably stink, this one seems pretty good. But it would need custom inductors I think so I can't immediately think of a use for it

Version 4 SHEET 1 2392 1316 WIRE 128 -768 -576 -768 WIRE 448 -768 128 -768 WIRE 672 -768 448 -768 WIRE 128 -624 128 -768 WIRE 448 -624 448 -768 WIRE 672 -400 672 -768 WIRE 224 -384 -352 -384 WIRE 448 -384 448 -544 WIRE 448 -384 304 -384 WIRE 512 -384 448 -384 WIRE 624 -384 576 -384 WIRE 128 -208 128 -544 WIRE 864 -208 128 -208 WIRE 1088 -208 864 -208 WIRE 1376 -208 1152 -208 WIRE 1552 -208 1376 -208 WIRE 1872 -208 1632 -208 WIRE 2176 -208 1872 -208 WIRE 2272 -208 2176 -208 WIRE -352 -80 -352 -384 WIRE 864 -64 864 -208 WIRE 1376 -48 1376 -208 WIRE 1376 16 1376 0 WIRE 2176 64 2176 -208 WIRE -576 80 -576 -768 WIRE 864 80 864 0 WIRE 1376 80 1376 16 WIRE 1872 80 1872 -208 WIRE 128 288 128 -208 WIRE -352 368 -352 -16 WIRE -256 368 -352 368 WIRE -112 368 -176 368 WIRE -32 368 -112 368 WIRE 80 368 32 368 WIRE 672 368 672 -304 WIRE 864 368 1376 80 WIRE 864 368 672 368 WIRE 1104 368 864 368 WIRE 1392 368 864 80 WIRE 1392 368 1168 368 WIRE 1872 368 1872 144 WIRE 1872 368 1392 368 WIRE 2176 368 2176 144 WIRE 2176 368 1872 368 WIRE 2256 368 2176 368 WIRE 2176 480 2176 368 WIRE -112 512 -112 368 WIRE 672 608 672 368 WIRE 2176 624 2176 560 WIRE -576 800 -576 160 WIRE -112 800 -112 592 WIRE -112 800 -576 800 WIRE 128 800 128 384 WIRE 128 800 -112 800 WIRE 576 800 128 800 WIRE 672 800 672 688 WIRE 672 800 576 800 WIRE 576 848 576 800 WIRE -352 912 -352 368 WIRE -352 1296 -352 992 FLAG 576 848 0 FLAG -352 1296 0 FLAG 2176 624 0 FLAG 2272 -208 Out- IOPIN 2272 -208 Out FLAG 2256 368 Out+ IOPIN 2256 368 Out SYMBOL voltage -576 64 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL nmos 80 288 R0 SYMATTR InstName M1 SYMATTR Value Si3440DV SYMBOL cap 1152 -224 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 40 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 0.47µ SYMBOL cap 1168 352 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 0.47µ SYMBOL schottky 1360 -48 R0 SYMATTR InstName D1 SYMATTR Value RB238T150 SYMATTR Description Diode SYMATTR Type diode SYMBOL ind2 1536 -192 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L3 SYMATTR Value 220µ SYMBOL schottky 848 -64 R0 SYMATTR InstName D2 SYMATTR Value RB238T150 SYMATTR Description Diode SYMATTR Type diode SYMBOL voltage -352 896 R0 WINDOW 3 52 50 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value PULSE(0 5 0 10n 10n 0.0000122 0.0000142) SYMATTR InstName V2 SYMBOL cap 1856 80 R0 SYMATTR InstName C4 SYMATTR Value 4.7µ SYMBOL ind2 144 -528 R180 WINDOW 0 36 80 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName L1 SYMATTR Value 220µ SYMBOL ind2 688 704 R180 WINDOW 0 36 80 Left 2 WINDOW 3 36 40 Left 2 SYMATTR InstName L2 SYMATTR Value 220µ SYMBOL res 2160 464 R0 SYMATTR InstName R1 SYMATTR Value 1Meg SYMBOL Digital\\inv -416 -16 R270 SYMATTR InstName A1 SYMATTR SpiceLine Vhigh=5V,Td=5e-9,Trise=100n SYMBOL pmos 624 -304 M180 SYMATTR InstName M2 SYMATTR Value QS8M51_P SYMBOL ind2 208 -368 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L6 SYMATTR Value 2.2µ SYMBOL ind2 -272 384 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L7 SYMATTR Value 2.2µ SYMBOL res -128 496 R0 SYMATTR InstName R3 SYMATTR Value 10k SYMBOL res 432 -640 R0 SYMATTR InstName R4 SYMATTR Value 10k SYMBOL FerriteBead 544 -384 R90 WINDOW 0 -16 0 VBottom 2 SYMATTR InstName L4 SYMATTR Value 3.2n SYMATTR SpiceLine Ipk=2 Rser=0.064 Rpar=620 Cpar=1.1p mfg="Würth Elektronik" pn="782763621 WE-CBA 1206" SYMBOL FerriteBead 0 368 R90 WINDOW 0 -16 0 VBottom 2 SYMATTR InstName L5 SYMATTR Value 3.2n SYMATTR SpiceLine Ipk=2 Rser=0.064 Rpar=620 Cpar=1.1p mfg="Würth Elektronik" pn="782763621 WE-CBA 1206" SYMBOL res 2160 48 R0 SYMATTR InstName Rload1 SYMATTR Value 10k TEXT -760 560 Left 2 !.tran 0.1 TEXT 200 -568 Left 2 !K1 L1 L6 0.99 TEXT 256 464 Left 2 !K2 L7 L2 0.99

Would Dr. Carl Sagan testifying before congress in 1985 about greenhouse gasses and climate change be too far off-topic?

On a sunny day (Tue, 23 Nov 2021 11:58:55 -0800 (PST)) it happened Rich S snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:

China agent man wrote "stop insulting Chinese leader."

This is Usenet get Used to it Its a free world.

One of the last possibly before you get jabbed and chipped and controlled by Big Brothel.

You posting had no electronic content, complainer.

On a sunny day (Tue, 23 Nov 2021 16:11:13 -0800) it happened John Robertson snipped-for-privacy@flippers.com wrote in <kYOdnS1cYIW snipped-for-privacy@giganews.com:

In the long ago days there was much in hacker grousp like alt.satellite.tv.europe I think it was, about hacking smartcards (especially with PIC micros) Power supply variations and other tricks to make it list ROM / FLASH content etc. Many papers were on the internet from very high tech like opening the chip and probing the SillyCon to relative simple solutions. I admit to playing with it :-) Not sure how much is preserved, google.

On a sunny day (Tue, 23 Nov 2021 16:11:13 -0800) it happened John Robertson snipped-for-privacy@flippers.com wrote in <kYOdnS1cYIW snipped-for-privacy@giganews.com:

In the long ago days there was much in hacker grousp like alt.satellite.tv.europe I think it was, about hacking smartcards (especially with PIC micros) Power supply variations and other tricks to make it list ROM / FLASH content etc. Many papers were on the internet from very high tech like opening the chip and probing the SillyCon to relative simple solutions. I admit to playing with it :-) Not sure how much is preserved, google.

The majority of threads are on-topic, but they usually don't require many posts to solve the issue.

Indeed, Tom, probably often correct. The on topic threads are resolvable (not so subjective, not generally inflammatory).

It seems /some/ of us revel in the knee-jerk emotional responses, jabe your fellow s-e-d poster, pulling people's chain, stoking the fires, etc. I never suggested we could ban all things off-topic.

I just wanted us to pause & think about it, at least.

And, it's good; I see some good points.

Maybe this group is mis-named. The world of electronic engineering is more than "design".

Maybe the amount of design posted here really reflects reality? --there isn't That Much new design work taking place? Most things are re-hashes of standard designs?

This audience is doing many other things aside from pure design work. Still electronic-related. And challenging.

thanks = RS