Wiring a VL53L1X Breakout board, the datasheet (attached) confuses me

[JamesTheEighth]

Hi,
I bought a VL53L1X Breakout board ToF sensor that I want to connect to a Raspberry Pi 3.
I need to connect the VIN, GND, SDA and SCL.
The documentation shows which pins are what, but it confuses me, as the layout in the documentation seems to be different than the boards itself.

Of the 10 pin holes on the board, one hole has a square around it, indiciating that would be pin 1. Across would be pin 2, and then on to the next row for the rest.
The square is on the outside column of the board.
However in the documentation pin 1 is on the inside column of the board.

What is the correct way to connect this?
VIN isn't specified on the board, does it have adifferent name?

I'm new to all of this, so I'm sorry if I ask the obvious.
Any help much appreciated.

[Andrew Neil]

You mean this: https://www.st.com/en/evaluation-tools/vl53l1x-satel.html ?

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@JamesTheEighth wrote:

Of the 10 pin holes on the board, one hole has a square around it, indiciating that would be pin 1. Across would be pin 2, and then on to the next row for the rest.

Indeed.

Also, looking at the board & carrying on with that counting would say that pin 6 must be ground:

Which corresponds to the Data Brief:

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@JamesTheEighth wrote:

However in the documentation pin 1 is on the inside column of the board.

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Which document are you referring to?

I only see that DB3555 Data Brief, and the only board layout in that is the photo:

[JamesTheEighth]

Thank you for responding so swiftly.
I am indeed referencing the DB 3555 Rev2 manual, it has the diagram on page 3.

I read about the pin order and the little square on Chatgpt, so I want to double check:
Is the square indeed  on all PCB's always number 1, and is number two always next to it?

You said you could tell 6 is the ground by looking at the board. Is that because of the four tiny dots around it?

Thanks!

[John E KVAM · Accepted solution]

In Andrew Neil's reply remove the question marks. He's exactly right. 

There is a user manual:

How to use the VL53L1 with STMicroelectronics' X-CUBE-TOF1 Time-of-Flight sensor software packages for STM32CubeMX - User manual

that shows:

We built those satellite boards to fit directly onto the X-Nucleo boards.

the datasheet of the X-Nucleo board shows:

And that should make it clearer. 

- john

[JamesTheEighth]

I forgot to confirm, it's indeed about the part that you linked at the beginning of your message.

[Andrew Neil]

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@JamesTheEighth wrote:

I am indeed referencing the DB 3555 Rev2 manual, it has the diagram on page 3.

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you mean this:

That's a schematic - there's nothing on that which specifies physical positioning.

Schematics are about connections - not physical layout.

They are topological - not topographical.

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@JamesTheEighth wrote:

Is the square indeed  on all PCB's always number 1

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It is a common practice.

[Andrew Neil]

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@John E KVAM wrote:

He's exactly right. 

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Thanks!

ST are by no means the only ones guilty of this - this is an all too common documentation fail.

Pin numbering needs to be explicitly and clearly defined:

• Where is pin one?
• How does the numbering go from there?

[Andrew Neil]

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@JamesTheEighth wrote:

You said you could tell 6 is the ground by looking at the board. Is that because of the four tiny dots around it?

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If you look closely, you can see that they're not just dots - they are connections to the ground plane:

[JamesTheEighth]

okay that's very clear thank you

[JamesTheEighth]

amazing, learned something new!