I would greatly appreciate any help on the following problem:
I have a running application for the MPU-6050 with MPL1. It works with a silicon revision that is commented as "(A2/C2-1)" in mldl_cfg.c (index = 6). We only got three chips with this silicon revision, afterwards we got a number of chips that have prod_ver=4 and prod_rev=1 (see mldl_cfg.c of MPL2).
While communication with the chips work the values I get are incorrect.
I have attached screenshots of debug data that shows the FIFO, the decoded values and so on. The chip was lying horizontally with no motion applied. I also attached a graph of several values over time.
I assume that there is some configuration or decoding problem so please give me hints.
Many thanks in advance.
This is the content of the FIFO (breakpoint in inv_process_fifo_packet):
These are the decoded values from fifo_obj:
These are the offsets from fifo_obj:
These are other values from fifo_obj:
These are several values over time:
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Re: Re: MPL2 with MPU-6050 incorrect values
Can you let us know which silicon revision you are using. The letter on the bottom right of the device package indicates the revision code.
The data you have sent is difficult to read on the forum. Can you send the data as an attachment to developers@invensense.com so that we can look into this issue.
Re: Re: MPL2 with MPU-6050 incorrect values
Hi,
I have already sent you two e-mails with the information. It would be very nice if you could give me a hint, it is already VERY urgent.
Many thanks in advance.
Re: Re: MPL2 with MPU-6050 incorrect values
The reason you are reading incorrect values is because you may be using the incorrect version (A2) of the Embedded MotionApps library. The correct library you should be using is version B1.
Re: Re: MPL2 with MPU-6050 incorrect values
First of all many thanks for your help.
I downloaded the B1 version and integrated it. However, a file comparison showed that the only difference was some changes in mldl_cfg.c to support new product and silicon revisions.
As this didn't change anything I analyzed the registers according to the "Register Map And Descriptions Revision 3.2".
I directly read the registers to get gyro and acceleration values and these are the results:
Gyro without self test (GYRO_CONFIG = 0x18)
0x0550 = 1360 = 83 °/s
0xF9A9 = -1623 = -99 °/s
0xFFF6 = -10 = 0.6 °/s
Gyro with self test (GYRO_CONFIG = 0xF8)
0x0689 = 1673 = 102,11 °/s
0xF807 = -2041 = -124,57 °/s
0xFFF2 = -14 = 0,85 °/s
Gyro 250°/s (GYRO_CONFIG = 0x00)
0x2AD6 = 10966 = 83 °/s
0xCDB7 = -12873 = -98 °/s
0x0082 = 130 = 0.99 °/s
Accel without self test (ACCEL_CONFIG = 0x00)
0x30F2 = 12530 = 0,76 g
0x2E88 = 11912 = 0,72 g
0x7FFF = 32767 = 2 g
Accel with self test (ACCEL_CONFIG = 0xE0)
0x1A46 = 6726 = = 0,41 g
0x0DBC = 3516 = 0,21 g
0x7FFF = 32767 = 2 g
Temperature:
0xF85E = -1954 = 32,15
If I understood the description of the self test feature for gyro and acceleroemeter correctly that would mean that this chip does not pass the self test.
Also I attached screenshots of the whole register list. I sent these screenshots to the developers e-mail address also.
Tomorrow I will have access to other boards with MPU-6050 and will make the same tests on them. I know that we have two other boards which exhibit a similar behaviour as the one the tests above were done with, but we still have more boards and maybe I just really had bad luck with the boards I took from the series.
However, I would really appreciate it greatly if you could tell me if the measurement results above indeed indicate that the chip under test has some hardware problem or not.
Many thanks in advance.
Re: Re: MPL2 with MPU-6050 incorrect values
The X and Y self test values of the gyro and accelerometer that you are reading are correct and as expected. Please refer to page 12 and page 13 of the MPU 6050 product spec for the gyro and accelerometer self test response limits.
The Z self test response of the gyro and accelerometer deos not seem to change. Can you let us know if you enabled the self test feature of the gyro and accelerometer for the Z-axis.