1 5 6 7 8 9 10 136 Replies Latest reply on Mar 31, 2020 5:54 AM by Fred27 Go to original post

Michael just a very quick note. here is a solution by the way very dangerous! Things will need.

1. DVM (two would be nice)
2. Paper and pen.
3. a very small transformer with 1.0 to 5.0 vac a wall wart will do, btw. (try to find one with a non-fractional output.

Heres the process. tools just paper and a pen and your DVM.

**** Major Hint If you have two sets of pins or wires most likely that one is primary and the other is secondary.

**** transformer primaries come in two forms one coil or two coils

So let's say that one side of your transformer has 4 wires ie most likely this is 110/200 split winding. check the windings label them A B C D, now with DVM check the resistance  and write it down from A to B, A to C, and A to D you should have some value of R between two of the wires, If not use B as the common again C as the common, and then D as the common.

Now do the same thing with the other side of the transformer.

Once the winding pairs have been identified now take your wall wart and hook it up to one of the windings. If you have chosen correctly you should see voltage on all pairs. As Transformers are expressed as Transformer

Wattage ::= Primary == Secondary. And we know what our input voltage was (say 10vac) and you hit a primary (woopie) by using 110vac as the norm your factor is 11 so let's say on one of the other windings about 1 volt you just found the 12 vac winding.

*****BUT*****

lets say you put that 10vac on the 12vac leads probing around could kill you as you will have now 110vac in the wild.

***

Fins use Barrier Strips.

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RF: antennas, distributed element circuits, filters, oscillators, etc
power and signal integrity.

photonics

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More about basics in AI... much  more!

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Memories. RAM, ROM and various types of memories. Memory in an IC and their implementation with address line and data lines. Interfacing of memory chips.

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Oh PLEASE, NO DRAMS TOO MUCH PROBLEMS,

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Given the large range of mcu.s available a course on some definitive way of selecting the best for a particular job. This should not necessarily go to the level of selecting a particular device but at least select a manufacturer taking into account the programming level, and language ie microchip for example program very simply at assembler level with few commands to learn Others require a knowledge of higher languages but once past the (sometimes steep) learning curve of the new language may prove far easier to use, perhaps better or not.

I have almost exclusively used microchip devices and assembler - yes Iam a bit old fasioned but in the end the devices have done what I wanted - perhaps not in the best way.and sometimes definately not the easiest It would be nice to have a wider selectionof devices sometimes but the learning path of any new assbler or new lanuage needs to be worthwhile

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How about a topic focused on Embedded Linux?  It could be an "Part II" extension to the existing Single Board Computers (SBC) learning module.

The topic could introduce different Embedded Linux build systems (Yocto, builtroot, OpenWRT, etc.), highlight their differences, suitability for different types of projects, relationship with hardware (device tree), boot process (including uboot), and more!

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robotics

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BTW there is really nothing mysterious about the term "embedded"  its way overused, it is just a smaller kernel and the small bords are getting bigger, look at a laptop is that embedded? Yes. the line is very burly. Get out your dousing rods or the wigi board.

I have a great working relationship with some of the projects as I have used them in one form or another. Basically, let us start with OpenWRT:  This just a group of very small images that can be used to flash routers, Like LinkSys. etc. It's all there. but not very useful for much else.

Yocto: Now this beast is a neat way to build a custom distro. So if you want for example like my RSS, and some other boxes that in my simulator, NexGen, I can add, remove things from my deliverables, Like things I need a full system when I do development and testing, but, on my release distro, I can remove a lot of things my system does not use, and other things it must have. for instance, I don't need, games, browser(s), compilers and a lot of other trash. But on the other hand, I need things like the full TCP/.IP stack (and there are parts not included like some routing protocols), LUA, Phyton(?), Java, and Seat Control (UNIX speak for users).  My Distro is built on 3  images:

1) The OS itself.

2) The extra stuff.

3) Deliverable Software.

on other things I just use grub!

Some of the servers use the boot system that has been around since before Windose! That is TFTP boot. If you wish to read more there is a very good write up here!

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Hi Cris, good observation and I agree that what is/isn't "embedded" is rather blurred.  I would have called a system embedded if it were a specific/tailored hardware platform that includes microcontroller vs mircoprocessor, that is, high level of integration of GPIO, peripherals, SRAM, flash, etc. into the main processing chip.  This is a very constrained view...now even Raspberry Pi can be considered an embedded platform and yet it is entire computer!  Definitely very blurred!

I like your suggestion to start with OpenWRT because its the most simplest framework...the easiest to understand.  Would be nice to include u-boot in the discussion (or cover it separately first) to understand the boot process from the very beginning.

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I included a link to uboot (unix) which is really tfpboot

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my bad! uboot and tftpboot are very similar where tftpboot asks the tftp server for its ip-adder etc and a small boot loader which invokes ftp if I remember correctly. uboot could be embedded into a chunk of flash which does things similarly to tftp. At some time they after they have their address and image info they both get it via ftp. in a Unix environment, your home directory  is stored on the server at

/export/home/uname and the client remotely mounts the directory via NFS

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