a thread about janitoring individual bits and using oscilloscopes and stuff

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > a thread about janitoring individual bits and using oscilloscopes and stuff

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

longview posted:

made even more cables, getting better each time

real happy with the brady bmp21 labelmaker, prints right on shrink tubes and it looks pro as gently caress, labelling on each end of the cable. only annoyance is the tubes are a bit hard to shrink all the way and its tedious with 60+ labels to shrink, and the smallest size doesn't fit anything smaller than ~AWG 18 neatly.

today i brought it to a whole 'nother level, brought out the lacing thread and proper knot technique, a bit tricky to make good ends with PTFE wiring but it's doable
still glad we're outsourcing most of this for production, but it's nice to have properly built prototype hardware instead of hundreds of unlabelled flying leads, and i'll still get to do some patch wiring with all the wank i want for the final hardware

the bmp21 is good

# ¿ Dec 4, 2014 19:58

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# ¿ Apr 29, 2024 09:00

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Bloody posted:

dang, i want that

# ¿ Dec 12, 2014 16:51

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

I'm an expert in applied gasinass physics

# ¿ Dec 20, 2014 04:18

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

I really don't even know what an ossciloscope is or measures but it seems cool as hell

# ¿ Dec 25, 2014 01:19

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Thanks to u both

# ¿ Dec 25, 2014 03:24

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Bloody posted:

Oscilloscopes enable time domain visualization of electrical signals. The more you spend, the finer the time domain detail you can see.

this is quite explanatory thank you

# ¿ Dec 25, 2014 04:38

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Olivil posted:

crossposting

# ¿ Dec 28, 2014 23:27

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

longview posted:

effortpost on single ended logic:
the real issue also involves the speed of signal transmission, the speed of light is finite in a wire (and in free space), in a pcb its around half the free space speed

if a digital line is 1 ns long (~5-6" in a PCB, or around 1 standard western dick) and you're driving a signal that takes 10 ns to move from 0 to 1, no problem, if it takes 100ps then you need to terminate the signal properly or the signal edge will reflect when it reaches the end of the line and come back, if the source isn't matched either it tends to keep bouncing back and forth until it settles.
series termination is preferred where possible since it's simple and just means adding a resistor to each line at the worst, sometimes AC termination is used but this tends to cause more problems than it solves in my experience
the voltage at the signal input may have oscillated a few times before settling, which can cause real problems if the voltage at the end of the line oscillates down to logic 0 before settling, fast logic may pick this up as a double clock, even if the actual clock speed is slow as balls

additionally the capacitance in the line needs to be charged at the slew rate (rate of voltage change) if there's a lot of inductance between the grounds of two devices then that fast edge will create a voltage between "true ground" and the driver and the receiver grounds, which further reduces the signal to noise ratio
this is why fast logic and solderless breadboards dont play nice together, the leads used for power and ground are just too long

for real fast poo poo the bond wires inside the package cause the same problem, which is why modern ICs often come with a big ground pad in the middle (QFNs, some QFPs etc.), DIP packages are usually right out since the pin spacing forces long bond wires inside the package that may actually make the IC unusable

CMOS logic basically connects each output to either VCC or ground, which also means that for most devices the current draw of a CMOS device is very low until you try to drive an output, when going from 0 to 1 on the output the driver will be connected from ground to VCC, the current going into the line (charging all that capacitance) has to come from the power supply, so the current waveform of a CMOS device will be a series of pulses with the same rise time and frequency as the sum of all the outputs, i.e. a series of very high frequency pulses
if you forget to put bypass caps near the IC then the inductance in a power supply lead will cause the supply voltage to sag during the transitions, this results in a lovely signal on the output, and may cause problems for the IC if the voltage drops below the minimum operation voltage

this is one of the many reasons LVDS and similar differential serial protocols are heavily used in modern designs, ground potential between devices matters a lot less when the signal is differential and ideally the sum of the current draw when two outputs are differential is more or less constant

v interesting, thanks

# ¿ Dec 30, 2014 00:42

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Bloody posted:

my usb datalink occasionally backpressures hard enough that the itty bitty fifo has to dump data on the floor. possible solutions:
fix the usb datalink to be more reliable
add a fuckoff big fifo

guess what im going to propose in the next rev of this prototype

wish you're posts were dumped on the floor

# ¿ Dec 7, 2015 21:50

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Bloody posted:

fpgas are horror stories so good choice

fpga the 13th

# ¿ Dec 17, 2015 20:32

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

JawnV6 posted:

https://docs.google.com/presentation/d/1x7syhRv8Kxi78fpbcp4vSsslriGOj5cuHUgCUuZcZ3U/edit#slide=id.p

was my determinism rant here or the Terrible thread

terrible thread

# ¿ Mar 4, 2016 23:32

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

movax posted:

also you can do PCIe over fiber

# ¿ Mar 11, 2016 18:56

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

hobbesmaster posted:

that's all thunderbolt is

Yeah but now you are graphics card can be a mile away

# ¿ Mar 12, 2016 19:12

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

ur job, hope u find a new one soon

# ¿ May 3, 2016 20:00

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

spankmeister posted:

you people are wizards

# ¿ May 22, 2016 05:08

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Mr Dog posted:

speaking of xilinx and altera etc

http://yosefk.com/blog/i-cant-believe-im-praising-tcl.html

solid domain name, p interesting article

# ¿ Jun 1, 2016 18:36

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

eschaton posted:

a synthesizer the likes of which the late 80s could barely imagine

make it vaporwave as gently caress

# ¿ Jul 14, 2016 13:46

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

BangersInMyKnickers posted:

In ad is there a way to manually assign a computer to a specific site through policy instead of IP mappings? I think the answer is no, but I'm trying to get sites set up so we can support RODCs and the people who run the servers are asking weird questions and trying to avoid doing any work

I only have one site, op

# ¿ Sep 29, 2016 01:38

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

gonadic io posted:

brb putting on my woollen jumper, playing with my cats and some balloons, moonwalking across my carpet and then working with this �50 chip

video pls

# ¿ Jan 7, 2017 08:45

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# ¿ Apr 29, 2024 09:00

Captain Foo: May 11, 2004; we vibin'
we slidin'
we breathin'
we dyin'

Bloody posted:

the 0 x y 5 case was the hypothetical one with the pull up n poo poo

More like 4 x y 20 lmao

# ¿ Feb 20, 2017 00:11

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > a thread about janitoring individual bits and using oscilloscopes and stuff