# How do I make sense of schematic diagrams? [closed]

I was wondering if somebody could help in explaining to me what information the following two schematic diagrams show.

I am quite new to this so I would appreciate if someone could help me understanding the basics.

For example, why are the capacitors placed where they are?

What an MPU CLK? MPU SIMO ?

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## closed as not a real question by Nick Alexeev♦, Leon Heller, The Photon, Dave Tweed♦, Connor WolfDec 24 '12 at 8:24

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Did you try to type the part numbers for the IC's in Google and check the datasheet for them? MIC5219-3.0YML and MPU-6000 –  jippie Dec 23 '12 at 22:46
The entire data sheet is 6 pages. Should I put the whole thing on here? I guess my main question is how does someone go about putting the pieces together? –  user1068636 Dec 23 '12 at 23:20
@user1068636 Link to the datasheets somewhere (e.g. the sites where you took them from). –  Renan Dec 24 '12 at 0:48
Why did you flag your own question? Do you want to have it removed? You can also edit it, if you think it can be turned into a good question. Then we can also reopen it. –  clabacchio Dec 24 '12 at 10:52

I think your question is part of a much larger one - i.e. how to get started with datasheets and schematics in general (or something along those lines)

Basically, the answer is to read a lot, and re-read a lot too. Eventually you begin to recognise common pin names, functions, component uses (depending on context - components may have many uses depending on situation)

Acronyms you become familiar with are things like SIMO (Slave In, Master Out - you will also see MOSI, MISO, or SDI, SDO, SCK, etc - these all refer to the SPI standard. Check the first paragraph of link for naming conventions)
In this case the MPU_CLK is the SPI clock, we can tell because it is connected to the SCK pin, which is the SPI clock pin for the IC. The SIMO is connected to SDI, which means Serial Data In (the alternative naming convention to the MOSI/MISO mentioned above and in the Wiki link)

So, for the direct answer, everything is in the datasheets for the two chips, specifically these two tables:

You can see above that the CPOUT pin is the charge pump capacitor connection (this will be used for an internal boost circuit, often for generating the higher voltages necessary whilst programming e.g. a microcontroller/FPGA - in this case it seems it's supplying the X,Y and Z sections with a bias voltage, see clip below) So, this is why the cap is placed there (the datasheet will have details on the value to use.

The second part of your question is answered basically by the table above, this gives the pin number and description of function.

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Hi Oli - this is exactly what I needed. Awesome answer. –  user1068636 Dec 24 '12 at 4:09
Also, I'm just a little curious, how can I relate this to writing code for a specific schematic? –  user1068636 Dec 24 '12 at 4:13
@user1068636 - if you mean code for a microcontroller based schematic, then I would begin with a simple starter kit (e.g. PIC, Atmel, Arduino, MSP430, etc) and go through all the code examples step by step. Also get a breadboard and when you feel comfortable, build a circuit and do something like expand on one of the examples. When I was starting out I built my PIC circuits using veroboard/breadboard, and just experimented with stuff till I understood it. –  Oli Glaser Dec 24 '12 at 4:44
Also a general book "Pratical Electronics for Inventors" is worth grabbing - don't be put off by the title, it's an excellent intro to the world of electronics, and has very detailed sections on all the basic components, their variants, things to watch out for, etc. Have a search on here too, there are quite a few similar previous questions with good answers on this subject. If you still have specific questions, then just open another one (read the FAQ to make sure you get the best answers by asking a good question) –  Oli Glaser Dec 24 '12 at 4:48
Thanks so much for your comments! –  user1068636 Dec 24 '12 at 14:22

Your circuit diagrams are incomplete. Things like A1 MPU CLK are called net names, and all these labels with identical names are attached together ... somewhere ... It can be on the same drawing, it can be on another sheet. There is no way to know what is connected if you don't have the rest of the circuit diagrams.

For capacitor placement in the circuit diagram, it is pretty much convenience to the person who drew it. Some like it to resemble the physical PCB layout, some like it when the diagram just looks nice and tidy. Maybe this question is of some use: Rules and guidelines for drawing good schematics

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To make sense of the diagrams, you will need the datasheets for the devices in there and a larger part of the schematic (one which shows where MPU_CLK, MPU_SIMO etc... connect to). E.g. typing MPU-6000 into Google gives this.
Taking a stab at what's seen on the schematic: SIMO and SOMI are used for SPI communications (Slave In/Master Out and Slave Out/Master In respectively). CLK is the clock (presumably coming from the microcontroller/microprocessor being used) needed for the SPI communcation.