MSP430FR2355: detecting the orientation

SAli BEN SULEIMAN

Dear all

I have a circuit that contains msp430fr2355, this circuit reads and writes signals from the MCU to an electronic device and vise versa, I designed a pcb for this circuit and I should connect 9 pcb together as 3x3 matrix, these 9 pcb should interact to read write signals between them, until here there is no problem but if I change the orientation of any pcb the signal processing must differ inside the MCU , so how to tell the MCU about the orientation?

Thank you

over 7 years ago

0 Mike Tooma over 7 years ago

Genius 3255 points

Typically this is handled in many ways that include:
* Dip switches that indicate where in the matrix the PCB is.
* Communication packets that set the orientation.

0 SAli BEN SULEIMAN over 7 years ago in reply to Mike Tooma

Intellectual 780 points

Thanks for your reply, is it an automatic or adjusted manually? I'm looking for an automatic solution so there should not be any human interference.

0 Mike Tooma over 7 years ago in reply to SAli BEN SULEIMAN

Genius 3255 points

Dip switches are adjusted manually; packets can be automatic depending on your algorithm.
You will have to devise an algorithm to do this. The algorithm must handle different scenarios that can include the following:
* None of the devices has an address.
* A new device without an address is connected to other devices that have an address.

0 Yiding Luo over 7 years ago

TI__Expert 5490 points

You can also use 4 pins on the PCB goes to 4 directions to indicate the orientation and on the MCU side depends on which pin is connected to the MCU it can tell the orientation of the PCB.

Thanks,
Yiding

0 SAli BEN SULEIMAN over 7 years ago in reply to Yiding Luo

Intellectual 780 points

Thanks Yiding for your reply, I got your idea, but if I rotate the pcb 90 degrees clockwise or counter clockwise, the new side which is facing now the MCU should be treated as the previous side before the rotation, so I'm looking for something which tell the MCU the dynamic orientation or direction of the pcb

0 SAli BEN SULEIMAN over 7 years ago in reply to Mike Tooma

Intellectual 780 points

Thanks Mike for your reply, I'll look about this solution.

0 Yiding Luo over 7 years ago in reply to SAli BEN SULEIMAN

TI__Expert 5490 points

With the 4 different pins from the PCB on 4 directions, MCU should be able to tell which side was facing the MCU at any given time. Maybe I do not fully understand the end result you would like to achieve. Hope this helps.

Thanks,
Yiding

0 SAli BEN SULEIMAN over 7 years ago in reply to Yiding Luo

Intellectual 780 points

Thanks Yiding for your reply, so for example if we imagine the pcb is a square so I should use an extra pin in each side to tell the orientation, am I right ? so if we call the sides of this square as following: upper,east,lower,west side, and the corresponding pins as 1,2,3,4 respectively, and the MCU is now at the left side of this pcb by means that the west side of the pcb is facing the MCU which has a pin with a value 4, so if I rotate the pcb 90 degrees clockwise, the lower side will become the west side with its pin whuch has a value of 3 so the MCU still does not know that the lower becomes a west, so how to change the pin value from 3 to 4?

0 SAli BEN SULEIMAN over 7 years ago

Intellectual 780 points

Part Number: MSP430FR2355

Dear all,

I have a small square pcb 2cmX2cm that has the mentioned MCU, I'm looking for something that I can include it in this pcb to detect its position in a matrix of 3X3 PCBs, any idea?

Thanks

0 Yiding Luo over 7 years ago in reply to SAli BEN SULEIMAN

TI__Expert 5490 points

Hello SAli,

Maybe I did not understand this clearly. If you know the initial direction of the PCB and you assign a direction to a specific pin then when the pin is connected to the MCU the MCU will know which direction is facing the MCU which can be used to figure out the rest three directions right?

Thanks,
Yiding

0 SAli BEN SULEIMAN over 7 years ago in reply to Yiding Luo

Intellectual 780 points

Thanks Yiding Luo for your reply, it does not have an initial direction, what I'm doing now is trying to fix some parameters so if the PCB rotates in any direction it will not have any issue.

Thank you again

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430FR2355: detecting the orientation