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Another excellent response. Do you think it is worth consolidating all this into an artice?
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Hello,
I use Arduino Uno to read the voltage change across a Thermistor terminals.
To read The temperature, I would use Steinhart–Hart equation:
I/T=A + B LnR + C (Ln R)^3 to convert voltage to temp, I can write this equation using C++ via Arduino IDE, then I'll get the Temperature.
My question is: how to do it without using the Arduino, I mean using only electronic components, what is the circuit design that can give me a Ln or cubic power?
Thank you
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The short answer is to start with Log amplifier - Wikipedia[^]. You can assemble a bunch of them to do the trick, but that is really doing tings the hard way. For limited temperature spans, there are simpler approximations for linearizing to a reasonable accuracy. Feed any search engine with "linearize thermistor"
Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012
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Thank you, your answer is helpful
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I’m trying to get a better understanding of how RAM memory works. I brought up this question before. This time I’m trying to find out a little bit more.
There is no optical fiber on the motherboard hence in the scenario where you want to place 32 bits in memory if you want to send them at one time you need 32 copper lines connecting the CPU socket to the memory slots. What happens if you want to send more information. Let’s say you want to send four 32 bit integers. Before sending the actual data does the CPU ( the Operating System) use the same 32 lines to instruct the memory slots where should the integers about to be sent be placed?
How does the memory know the address range in which it should place the four integers?
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CPU sockets of today has a tremendous number of 'pins' (they aren't really pins nowadays, but the name sticks), typically 1200-1500. Usually, far more than 32 of these carry data to/from RAM. More typical is 128 or 256, the length of a cache line. If you want to modify anything less (such as a single byte or a 32 bit word), the CPU must fetch the entire cache line from RAM, modify the part of it that you want to modify, and write the entire cache line back to memory.
The CPU uses another set of pins to indicate the RAM address to be read from or written to. Since the arrival of 32 bit CPUs, the CPU has rarely been built to handle as much RAM as the logical address space; the 386 did not have 32 address lines, you could not build a 386 PC with 4 GB memory. Nor does today's 64 bit CPUs have 64 address lines. The memory management system will map ("condense", if you like) the used memory pages spread over the entire 64 bit address space, even multiple 64 bit spaces - one for each process, down to the number of address pins required to cover the amount of physical RAM that you have got.
Note that when transfers between RAM and the CPU cache (inside the CPU chip) goes in units of an entire cache line of, say, 128 bits or 16 bytes, there is no need to tell the RAM which of the 16 byte(s) are actually used - they are transferred anyway. So there is no need to spend address lines for the lowermost 4 bits of byte address. The number of external pins is a significant cost factor in the production of a chip, so saving 4 bits gives an economic advantage.
In the old days, pins were even costlier, and you could see CPUs that first sent the memory address out on a set of pins during the first clock cycle. The memory circuits latched this address, for use in the next clock cycle, when the CPU transferred the data value to be written on the same pins as those used for the address. Or reading: In the first cycle, the CPU presents the address it wants to read; in the next cycle, the RAM returns the data on the combined address/data lines. There were even designs where the address was too long to be transferred in a single piece: In cycle 1, the high address were transferred, in cycle 2 the low address, and in cycle 3, data was transferred. (And in those days, you fetched/wrote a single byte at a time, and cache was rarely seen.)
This obviously put a cap on the machine speed, when you could retrieve/save another data byte no faster than one every two or three clock cycles. To win the speed race, general processors today have separate, wide address and data buses. I guess that you still can see multiplexed address/data buses in embedded processors (ask Honey about that!).
Your scenario with four 32 bit words to be saved: If they are placed at consecutive logical addresses, as if they were a 16 byte array, they might happen to fit into the same cache line. When the cache logic determines that it is necessary to write it back to RAM, one address is set up on the address lines, and a single transfer is made on the data lines. If the 16 bytes is not aligned with the cache borders, but spans two cache lines, each of the two parts are written to memory at different times, in two distinct operations. If the four words are located in distinct, no-coherent virtual addresses, they are written back to RAM in 4 distinct operations: 4 addresses on the address bus, each with a different cache line contents on the data bus. Note that the entire cache line is written in each of the write operations, and could include updates to other values in the same lines that hadn't yet made it to RAM.
Religious freedom is the freedom to say that two plus two make five.
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I get the picture, thank you
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I have been graciously given PCB with LED's to monitor SOME serial data. It has LED for DRX and DTX.
My current serial data code only sends and I have no connection to any "remote serial device" , but I can see both DRX and DTX flashing. Good.
BUT
why is DRX flashing?
Is is because my "serial data communication" is set for "local loop back"?
How do I verify my "modem" settings" AKA "AT" commands ?
Thanks
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jana_hus wrote: How do I verify my "modem" settings" AKA "AT" commands ?
Specific question gets a list of sites that can help you.
modem at commands - Google Search[^].
modified 10-Sep-24 16:14pm.
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FROM https://e-junction.co.jp/share/Cat-1_AT_Commands_Manual_rev1.1.pdf:
Quote: 2.29. Controls the setting of eDRX parameters +CEDRXS
Syntax
Command Possible Responses(s)
+CEDRXS=[<mode>,[,<acttype>[,<requested_edrx_value>]]]
+CME ERROR: <err>
+CEDRXS? [+CEDRXS: <acttype>,<requested_edrx_value>[<cr><lf>
+CEDRXS: <act-type>,<requested_edrx_value>[...]]]
+CEDRXS=? +CEDRXS: (list of supported <mode>s),(list of supported
<act-type>s),(list of supported <requested_edrx_value>s)
Description
The set command controls the setting of the UEs eDRX parameters. The command controls whether
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thanks for the reply.
I probably did not formulate my question correctly. I was not asking about AT commands.
I was trying to verify if some serial port parameters are being used to put the USB port itself into "loopback mode". Actually I am not sure if Linux serial port can use AT commands at all.
I guess I need to look if Linux has "default modem" anything.
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Hi Jana,
Can you try these
DRX Flashing (Local Loopback)
DRX flashing could be due to local loopback. Check and disable it with:
stty -F /dev/ttyUSB0 -echo
Use minicom to send AT commands:
sudo apt-get install minicom
Open your serial port:
sudo minicom -D /dev/ttyUSB0
Type AT to check response (OK if working).
I hope this will work for you and resolve your issue....... 
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So, over the last 20+ years, I think I'm on my 4th laptop. I buy them for development, and I specifically look for expandability and reliability. I rarely toss them (I'm working with my therapist on this). I used to buy Dell, but they got squirrely with their consumer brands (xps1530 was excellent except for the motherboard graphics chip set). The last Dell I bought was a precision M4700 and it's a beast. I've moved on to Eluktronics - sort of a custom maker, but damn good hardware. Just watch out when they solder ram to the motherboard, but that's on me. Anyway, back to the 4700...
So, not the thinnest or lightest, but excellent display, great keyboard, add SATA SSDs and it will just go. But I had this quirky issue where it would blue screen and weird random times. This has been happening for over 5 years. Cleaning it up, it needed a new battery - $40 later done. no more complaints about charges, but boom blue screen. On reboot, it kept fussing about losing it's BIOS settings. Now, when any computer says this, the battery backup on the motherboard is dead. I had never thought of this. These are $2 from your grocery store. $5 if dealing with Dell's stupid stuff.
The laptop has been sitting there running for 2 weeks, all issues resolved.
When in doubt, go for the simple solution.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
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Okay, I would like ideas from people that are smarter than I am about my next great USB plan.
THE PROBLEM...
I find that I keep on having these mysterious behaviors Which cost me over an hour to locate, and it always turns out to be that the USB hub has just plain and simply worn out physically.
MY NEXT SCHEME...
- Build my own computer
- Install a specific USB Expansion Controller Card Adapter (The more ports, the better)
- When I buy that card adapter, I will buy two or three (identical) replacements for the future when its jacks wear out
- Use the same cheap hubs that wear out after a year or two, And plug them into a specific Jack on the controller card.
Put this all together, and I'm wondering if this will provide me a workable solution until the time that USB goes away and is replaced with the next Disco Baboon Technology of the future
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C-P-User-3 wrote: I keep on having these mysterious behaviors Which cost me over an hour to locate, and it always turns out to be that the USB hub has just plain and simply worn out physically.
That description suggests this is not a hardware problem. Hubs should not really be breaking a lot.
Perhaps it is a usage problem.
Perhaps you throw your hubs, literally, into the back of a van when you go somewhere.
Maybe you are using the cable itself to pull out plugs. And at odd angles.
Maybe you are custom wiring something and the final product is a little rough around the edges.
At any rate for situations like that you should look at how you are treating the hub.
Alternatively you are running a business and you deliver systems and support them. And the hubs 'seem' to keep breaking.
Several possibilities there.
You have an employee that doesn't know what they are doing.
You should probably spend a bit more on the hubs that you buy. Cheap general means cheaper parts and construction.
Your customers are messing with something that probably shouldn't (see prior list for possibilities.)
One general solution if you do have something that you unplug and then plug back in a lot is to use a short extender cable. Plug that into the hub and leave it there. Then the other device is only plugged into the extender. If anything breaks then it is the extender.
And depending on the situation for the prior there are usb switches. Leave everything plugged in but use the switch to go back and forth.
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as jschell replied, need more details especially the type of failures.
Over the past 20+ years, I have worked with usb hubs and have had 0 failures. I lost a couple, but that's a different issue. On my banker's/lawyer's desk, I have two USB hubs that have been double stick taped there for at least 10 years. One is USB 2.0, because for a long time I have had to support an Xp development environment. The other is USB 3.0. because I support a Window 10/11 environment that uses newer usb hardware. The only problem I have found is dealing with USB adapters - serial devices, ethernet, and I mix them up.
Now I build my own machines. The BS from OEMs and the shortcuts they take, I just don't do that anymore. Would I install something in my desktop? Based on my experience, no. I'd daisy chain to an external hub.
The one thing that I have found that drives me as a developer near insane is the stupidity of Microsoft. It's starting to creep into Unix, but we shall see. Microsoft decided to help save power, so there are default setting that turn off your USB devices. OS update? Let's turn it off. Wait the user explicitly said not to do that - meh, f' the user, climate change. And their goes my 6 month soak test.
I have 15 years of h/w - laptops - around me. Almost all of my cycles (insert/remove/insert) are on the laptops. No failures. This leads me to suspect that something else is going on.
Charlie Gilley
“They who can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.” BF, 1759
Has never been more appropriate.
modified 27-Aug-24 8:28am.
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Where can I get and download CodeProject version 2.0.8 for my Windows 7 computer with Blue Iris? I've read that this version works well on Win 7. I want to try this version because the newer versions do not install properly.
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Greetings Kind Regards
I stupidly attempted to charge a hand held vacuum cleaner via one of the USB ports on my PC. Since then the screen has been blanking momentarily out periodically id est approximately 2-3m. Did I destroy this machine?
Thank You Kindly
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I would doubt that is the cause of the problem. USB provides limited power. The device can't suck out anything else. But if it did then it would more likely be a problem with the computer (poor design) and now the computer has a problem.
You didn't mention how old the computer/monitor is. They do fail. I have a failed monitor sitting on the floor next to my desk. That specific brand fries capacitors every couple of years. So I just need to break out the soldering iron open it up and replace them.
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Thank you for your kind and informative reply. The monitor is an ONN brand. The computer is a refurbished DELL OptiPlex 7040. Each are approximately 2y old as best as I recall. Oddly enough after turning the computer open side down to shake out any roaches which may have made a home inside the problem has not reappeared for several hours now. This also coincided w/ reading of the fix to the CrowdStrike outage which I assume does not affect me though it seems to have affected my doctors' office as they canceled my appointment for today for that stated reason.
Thank You Again Most Kindly
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BernardIE5317 wrote: The computer is a refurbished DELL OptiPlex 7040. Each are approximately 2y old as best as I recall.
The OptiPlex 7040 was introduced in 2015, so you are talking about a 9 year old computer, not a 2 year old.
If the problem manifests as the screen blanking out, and this disappeared after "shaking" the computer, I would suspect a soldering that has gone bad after nine years - not so bad that there is no connection ever, but vibrations can make it crack up, breaking contact, another shaking might bring the pieces together again. (Isn't that Gyro Gearloose who fixes cars by giving them a proper kick in the right place?  )
I agree with jschell: This probably has nothing to do with your USB Power Delivery. Even in USB 2.x, there was a negotiation between the consumer and the USB controller, the consumer asking for so-and-so many units. If this is within the capacity of the USB Host, there is no problem. If the request exceeds what is available, the host says: Sorry Dave, I'm afraid I can't do that, and it simply won't deliver what it can't deliver.
In any case, a USB interface has so little to do with your display interface that there is little probability that a problem with one would affect the other. I can imagine a poorly designed USB circuit not handling overload properly, causing other USB devices to fail - but not the display interface.
Religious freedom is the freedom to say that two plus two make five.
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trønderen wrote: The OptiPlex 7040 was introduced in 2015, so you are talking about a 9 year old computer, not a 2 year old.
Not to be picky, but maybe he bought it after 2015? Is it possible that they made that model for a few years?
The difficult we do right away...
...the impossible takes slightly longer.
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I am on a Windows 7 64 bit OS and have been using AOEMI BackUP ver 4.6.0 (old version)
I have created a Bootable Media and Incremental BackUP's on a External USB Hard Drive
The last backup was with a Asus PA248 Monitor which has decided to go south after 11 years
Now I have a Asus PA279CRV with no driver support for Windows 7 so I am using the driver from the Asus PA248
I have the screen resolution on the new monitor set to 1920 X 1200 same as the old monitor
Question: If I do a incremental backup now and in the future need to do a complete system restore
will the current incremental backup's think it is running the old monitor ?
Thus it might try to find a Asus PA248 and fail because that is no longer connected to the computer.
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Instead of "continuing" to do "incremental" backups, take a "full" backup now (or after any "changes"); then, continue with incremental backups (for that "full" backup).
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
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