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I was looking at the schematic of the LPCXPRESSO LPC1769 board from NXP and I couldn't figure out what they meant by "not mounted" which appears on the left corner of the following picture. not_mounted

Here's a link to the full pdf document (page 3): http://www.lpcware.com/system/files/LPCXpressoLPC1769revB.pdf

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'which you have not got ...' ... :-) – Russell McMahon Jun 28 '14 at 3:02
up vote 3 down vote accepted

Neither the bypass capacitor C34 nor the SPI flash chip U3 has been populated on the board (since they're both inside the dashed box).

The footprints for both are there, and you could add them yourself (look for the designators C34 and U3). Be sure to add the bypass capacitor C34, if it's not already there, should you decide to add the flash chip.

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It means that if you bought the board from NXP, the SPI flash chip would not be soldered to the board but there would be PCB provision for it to be fitted should you wish to buy it and fit it yourself.

That's how I read it anyway.

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"Not mounted" mean that components are expected on board but are not populated on sales board. Developer usually add "not mounted " (or NM) component on sales board because it is very helpfull. For example, flash component is helpfull for testing or reparing step, but not needed for sale version of board. just think to different version of same product (for example same pc, one with wi-fi module and one without).Manufacture just produce only one pcb (decrease cost!) and then assembly only required part on different version

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