### Author Topic: Circuit design question.  (Read 1835 times)

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#### henrysin44

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##### Circuit design question.
« on: July 15, 2014, 12:49:28 am »
I have included a picture. In the picture i circled 3 things, my question is how do thees three things correspond to the atmega circuit?
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#### Rigby

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##### Re: Circuit design question.
« Reply #1 on: July 15, 2014, 02:15:21 am »
Schematics nowadays don't have to have everything connected in the diagram.

Example, everything that says 5V in that drawing is direcly connected to everything else that says 5V.

The "video" pin on the ATmega is connected directly to the "video" pin in the center blue circle.  The "clock" and "data" pins in the lower blue circle are connected to the "clock" and "data" pins on the ATmega.

Make sense?

#### dsc-pcb

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##### Re: Circuit design question.
« Reply #2 on: July 27, 2014, 11:37:05 am »
Agree on 1st floor. It is very typical in block schemetics. For example, the SYNC in the middle is connected to ATMEGA PD5 SYNC. 5V is just from DC supply. Data in the lower circuit you made, is connected to ATMEGA PD0 as input.
« Last Edit: July 27, 2014, 11:43:32 am by dsc-pcb »

#### Wilksey

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##### Re: Circuit design question.
« Reply #3 on: July 28, 2014, 10:36:09 am »
Those are net labels, a way of joining 2 or more nets together when placing "wires" around the schematic makes it look messy, also useful since the dawn of multiple sheets / hierarchy as you can have the same nets on different sheets quite easily.

Most if not all packages support this.  When it comes to PCB layout all of the nets with the same name are electrically connected and you can see this reflected in the rats nest.

Smf