Question on VDD and VSS internal connection

[OLAMIDESET]

Should each vdd pin of the stm32f407zgt6 read continuity like the blue pill on multimeter, are they internally connected within the chip or separated? Similary for all the vss pins are they also all connected vss inside stm32f407zgt6

Thanks

[mƎALLEm]

Hello @OLAMIDESET and welcome to the ST community,

All VDD and VSS pins should be connected outside the chip (if this is the background of your question).

[OLAMIDESET]

I appreciate your prompt response. I know that all the vdd and vss pins should be connected and grounded with 100nf ceramic capacitor but what I'm saying is that before connecting any component at all, should each vdd pin read continuity on a multimeter and same thing with vss(are all vss internally grounded)?

[mƎALLEm]

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@OLAMIDESET wrote:

should each vdd pin read continuity on a multimeter and same thing with vss(are all vss internally grounded)?

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What is the background of that question? is that quiet important information to know?

[OLAMIDESET]

I'm making a custom-built board and want to clear any doubts before powering it up.

Can you assist with the answer on if the vdd pins are internally connected within the stm32f407zgt6 chip and same thing with each vss pin if they are internally connected and thus should read continuity. I don't mean any vdd reading continuity with any vss pin but vdd to vdd and vss to vss within the 144 pins.

I hope it's clear now.

[mƎALLEm · Accepted solution]

You can't rely on the continuity test for that as not all VDD pins are internally connected together. Same case for VSS.

I've just tested it in a free chip.

Hope I answered your question.

[OLAMIDESET]

Thank you, you did. Many of the vdd pins didn't beep internal connection same as vss pins and that confused me here too that's why I came to seek clarification from the forum especially when a customer care agent told me each vdd pin should read continuity and each vss pin against another vss pin for new chip.

I hope it's the result is right.

Thank you.

[mƎALLEm]

Ok if my previous post answered your question please accept it as solution.

Thank you

[Andrew Neil]

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@OLAMIDESET wrote:

I'm making a custom-built board and want to clear any doubts before powering it up..

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The instructions given are clear: When designing a PCB, you must ensure that all VSS pins are connected, and all VDD pins are connected - no room for any doubts in that!

https://www.st.com/resource/en/datasheet/stm32f407zg.pdf#page=79 

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@OLAMIDESET wrote:

like the blue pill.

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The blue pill is a board - not a chip.

[OLAMIDESET]

Yes I will but can you please provide a screenshot of the vdd pins that read continuity and vss pins that beep continuity on free stm32f407zgt6 chip? Thanks