nrf52 with MPU9255

[kirt]

Hi ,I am using nrf52 DK with mpu9255.I am using source code given here here.of this link,I have taken  'nrf5-ble-data-ready-interrupts' example .code  builts fine in keil v5 though.I am not getting accel values.

help will be appreciated.

[MartinBL]

Hi, 

I have pushed an updated 'nrf5-ble-data-ready-interrupts' example to github that I have tested with a PCA10056 and an MPU9255. 

Note that to use pin 17, 19, 20, and 21 on the PCA10056 you will need to cut some solder bridges and do some soldering as these pins are not actually connected to the P24 header on the kit by default (as is described in the image you have posted): Solder bridge configuration. 

[kirt]

Hi MartinBL,

I amnot using PCA 10056.I am using PCA10040.can you share link of updated git hub example

thank you

[MartinBL]

Then why did you post an image of the pin documentation for the PCA10056? The PCA10040 version on github should work out of the box. Have you tried the example with the default pins? You can't use pin 21 on the kit. Refer to the silkscreen below the kit to see why.

[kirt]

Yes,I cant use pin 21.

which pins of nrf52 dk do i need to use defualt pins  4,28,3,29 given in nrf_drv_mpu_spi.c ?

[kirt]

yes,I tried with default pins.

i didnot get accel values.I even tried to print on jlink  RTT viewer by giving some logs in main() function  .but nothing printed on jlink  RTT.

[kirt]

hi ,

Default pins   specified in nrf_drv_mpu_spi.c are  pin 4,28,3,29.do I  need to connect these 4 wires as shown in image 

[MartinBL]

Hi,

Can you try download a fresh copy of the examples from github and try again: Please use the pin described in the example:

In nrf_drv_mpu_spi.c:

#define MPU_SPI_MISO_PIN    28 // MPU SDO. 'AD0' on MPU breakout board silk screen
#define MPU_SPI_MOSI_PIN    4  // MPU SDI. 'SDA' on MPU breakout board silk screen
#define MPU_SPI_SCL_PIN     3  // MPU SCLK. 'SCL' on MPU breakout board silk screen
#define MPU_SPI_CS_PIN      29 // MPU nCS. 'NCS' on MPU breakout board silk screen

In main.c

#define MPU_MPU_INT_PIN     30

And remember to program the Softdevice in addition to the application. 

It should work straight out of the box. If it doesn't there must be something wrong with your kit, sensor, or wiring. 

[kirt]

hi,

I tried with fresh code form github.i am not able to see accel values .but before getting values i should get MPU BLE device in nrf connect Application.But i dont see such device under 'SCANNER' option in nrf connect (downloaded from nordic website).

i am using default pins as given in example.I am connecting pins as shown in image.Please have a look and correct me if wrong .

I have programmed nrf52 with softdevice s132.I have checked supply for MPU9255 (5v w.r.t GND) as shown in image and its 5 V dc 

[MartinBL]

Hi,

Have you remembered to program the Softdevice?

Can you program the attached test.hex file. That contains the softdevice and the application and should work. If not there is something wrong with your HW or wiring. 

test.hex

[kirt]

Hi

Yes,as mentioned earlier ,I have programmEd nrf52 dk with soft device s132 then loaded dk with example code.

Can you share your 52dk interfacing with mpu9255 diagram/image ?

[MartinBL]

Here you go:

Did you try my test hex file?

Note that I have bypassed the voltage regulator on my MPU9255 breakout board with a solder bridge. Hence I can feed it with VDD from my nRF52DK, and not 5V as it seems like you do.