[MMA8451Q] sensor toolbox question

[robinkim]

Hi, I am testing functions of MMA8451Q following user's guide and facing day1 problems...

1) Enabling Latch

the sensor does not work appropriately when the latch is enabled and Transient Interrupt is selected. My understanding is in the indicator light in the main screen shouldn't flip or stay red if the Transient detection tap is read.

figure1: Transient interrupt is sold red/flipping green (occassionally) as I shake the sensor (Threshold was set very low 0.6g).

2) Also, Directional Tap Low-Power with FIFO application never work. I set the values and ran active mode, tapped sensor, but nothing happens.. (Although tap is detected in Full System Evaluation application) .

figure2: Active mode and nothing appears (using MMA8451Q).

Can someone help me?

Thanks in advance for your time and help.

Robin

[troydaniel]

Hi Robin,

We have been doing some testing here and we believe the issue is a software (rather than hardware) issue.

We have been able to reproduce it on a machine here but we are still trying to figure out why it works on some machines and not others. I will let you know as soon as we make some progress but it may take some time as the issue is intermittent.

Thank you for your patience,

Troy

[robinkim]

Thanks Troy,

Can you please inform me when there's any update in software?

Robin

[troydaniel]

Hi Robin,

I will definitely let you know when we figure it out. It is proving annoyingly difficult to reproduce and resolve. I appreciate your patience.

Regards,

Troy

[troydaniel]

Hi Robin,

Just wanted to let you know that this is still on my plate.

Unfortunately I have been unable to reproduce this with any consistency. I can make it happen if I repeatedly switch between the Tap demo and the full system eval, but it seems that the issue may be in the embedded code (since the part stops sending data to the GUI) and I have no ability to debug that code (very old legacy code).

I honestly don't know what the difference is between the machines this is occurring on and ones that are working without error.

I'll continue to keep you up to date, but unless I make some sort of breakthrough I don't see this issue being resolved any time soon.

Regards,

Troy

[troydaniel]

Hi Robin,

The transient detection function is actually intended for the detection of "shake" events rather than 'tap" events, if you wish to detect single/double-tap events you may be better served by the "Pulse Detection" function of the demo.

Unfortunately the demo is not the best way to examine the Latch function. Since the Latch function holds the event active until the transient interrupt source register (TRANSIENT_SRC) is read (which it must be to toggle the indicator light in the GUI) the indicator will only toggle to green briefly (as the interrupt that toggles it also clears the bit and toggles it back to red), as such the Latch will never really be visible via the GUI.

I am currently unable to reproduce your issue with the Tap detection, I have tested it on two PCs here and both work out of the box with an 8451Q, do you have the latest version of the STB 4.2.1.17?

Hope this is helpful, please reply if you have any further questions or concerns.

Regards,

Troy

[robinkim]

Hi Troy,

Thanks for your suggestion on the Latch. I will check the function agian once I get to play with registers.

And about the "Directional Tap Low-Power with FIFO" application, the software version that I have (the one that I can download from the website) is STB 4.2.1.18, which I think is even a higher version. To appropriately check if this is not related to other hardware issue, can you please send me your version if possible?

Thanks much!

Robin

[troydaniel]

Hi Robin,

I unfortunately don't have an easy way to send you the earlier version I have (it is a large file as I do not have the installer for it anymore), but I have installed the newer version from the web and the tap demo continues to work for me. Also as a note, nothing about the MMA845xQ demo has been changed for many releases, so there should be no difference between .17 and .18.

The only significant difference between the Full System Eval and the Tap demo is that the Tap demo makes use of the on-board FIFO data structure. Unfortunately this means that I can't have you try it with any of the other boards as only the 8451 has a FIFO. Do you happen to have another 8451 board available that you might be able to try it with? This is honestly the first time an issue has cropped up in which a functionality worked in one demo but not another and on one PC but not another, so I am having difficulty directing you to a good test to determine root cause.

Out of curiosity, is the board connected directly to a USB port on your PC or connected via a USB hub? Other people have experienced issues when trying to connect via a hub in the past (though this was with connecting in the first place, rather than with a specific demo not working).

[robinkim]

Hi Troy,

Thanks for checking that for me. FIFO is not working yet. The board is powered directly through my PC and changed port with different ones as well.

We might plan to purchase 2nd one to see if this is a hardware issue.

If so, is there any way that we can get this replaced?

Many Thanks,

Robin