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ADIS16375 with ADIS16IMU/PCBZ , problem in getting output

Question asked by paulstavrou on Mar 27, 2015
Latest reply on May 5, 2015 by NevadaMark



I have installed the ADIS16375IMU (ADIS16375BMLZ) onto the ADIS16IMU/PCBZ board in order to interface it to a TI Tiva micro-controller via SPI.


Having read relative posts on the AD forum concerning the start-up behaviour of the IMU and respective interfacing issues I am still a bit puzzled on how to solve my issue.


First and foremost, following the wiki page for ADIS16IMU/PCBZ I have install the JP1 jumper , but the C1 and C2 are not populated. Since I am a software engineer , I am confused as to if I should install capacitors on the PCB in order to achieve correct operation. I am not interested on the RTC functionality of the IMU itself.


I have developed the SPI driver, using MODE_3 and 16bit length , MSB first , running at a CLK of 12 MHZ (also tested lower clock speeds). I can successfully read the PROD_ID, TEMP_OUT register every time without an issue. But when I attempt to read the ACCEL_OUT and GYRO_OUT registers I get inconsistent output.


I am powering the PCB from a power supply unit, and have twisted the cables as discussed in previous posts. The unit seems to be drawing a current of 0.16 A at 3.46 Volts.



Below you can see an example of the data I am getting ( btw I use the interrupt on DIO2 in order to commence data reading and have also tried reading data without using the interrupt, just with proper timing between writes and reads). Values are printed out both in decimal and hex for reference.


27/03/2015 13:12:25.943 [RX] -

ACC_X_OUT : -24832 0x9f00

ACC_Y_OUT : 1746 0x6d2

ACC_Z_OUT : 19641 0x4cb9

GYRO_X_OUT : -15392 0xc3e0

GYRO_Y_OUT : -23096 0xa5c8

GYRO_Z_OUT : 29869 0x74ad


27/03/2015 13:12:26.320 [RX] -

ACC_X_OUT : 9089 0x2381

ACC_Y_OUT : -21731 0xab1d

ACC_Z_OUT : 9142 0x23b6

GYRO_X_OUT : -4406 0xeeca

GYRO_Y_OUT : 16218 0x3f5a

GYRO_Z_OUT : -29740 0x8bd4


27/03/2015 13:12:30.816 [RX] - Temp : 0xff20 23.734400

27/03/2015 13:12:31.378 [RX] - Temp : 0xff1e 23.723100

27/03/2015 13:12:31.972 [RX] - Temp : 0xff23 23.751350

27/03/2015 13:12:32.488 [RX] - Temp : 0xff21 23.740050


I am also attaching some pictures of from the board connections.


I have also tried installing a capacitor (max 10V, 1500uF) in the VDD and GND connection but that did not have any effect.


Could you provide me with some insight as to what might be the problem or what to do in order to figure it out.


Thank you in advance,