About Anatol

Hi  BSTRobin.  1. Yes, I edited those functions implementing Arduino "Wire" library into them, it worked well polling separate readings. I guess the main problem is that library has buffer 32 bytes only, but to read fifo I need 2000+ bytes in a burst read. I tried several others I2C libraries but no luck, they either has the buffer length defined as 8 bits variable so limiting to 256 bytes (including Wire lib), or linked to others libraries and doesn't compile without them. If anyone could point out an Arduino solution to read 2000 bytes in burst - it would be appretiated very much. 2. ODR is 50 Hz, so fifo is defenitely overflown. ... View more

I tried to parse the signal manually, got: 0x68, write, ack, 0x1D (INT_STATUS_1), write, ack 0.9 ms 0x68, read, ack, 0xC1 bin 1100 0001 (?), nack, 0(?) 0.9 ms 0x68, write, ack, 0x24 (FIFO_LENGTH_0), write, ack 0.8 ms 0x68, read, ack, bin 11100000 ack 00000 (?) 2.5 ms 0x68, write, ack, 0x26 (FIFO_DATA), write, ack 2.5 ms 0x68, write??, ack, 0x48 (FIFO_CONFIG_0), write, ack 1.2 ms 0x68, read, ACK, bin 0000 0010 1100 0000 1(nack?) 1110 1000 0 0000 1110 000 (?) 1 ms 0x68, read, ACK, bin 0000 0000 ack 1100 0001 1(nack?) 0(?) ... View more

Below is the function called each 2 seconds to read FIFO. I believe it should work the same way as called by an interrupt? I mean to read the whole FIFO length, no matter owerflow or no overflow the data is? void readFifo(){ uint8_t index; // rslt = bmi2_get_fifo_length(&fifo_length, &bmi2_dev); rslt = bmi2_get_fifo_length(&fifo_length, &bmi2); // bmi2_error_codes_print_result(rslt); //fifo_length = 170; //Serial.println(fifo_length); accel_frame_length = BMI2_FIFO_ACCEL_FRAME_COUNT; gyro_frame_length = BMI2_FIFO_GYRO_FRAME_COUNT; /* Updating FIFO length to be read based on available length and dummy byte updation */ fifoframe.length = fifo_length + bmi2_dev.dummy_byte; printf("\nFIFO data bytes available : %d \n", fifo_length); printf("\nFIFO data bytes requested : %d \n", fifoframe.length); /* Read FIFO data. */ rslt = bmi2_read_fifo_data(&fifoframe, &bmi2); // bmi2_error_codes_print_result(rslt); /* Read FIFO data on interrupt. */ rslt = bmi2_get_int_status(&int_status, &bmi2); // bmi2_error_codes_print_result(rslt); if (rslt == BMI2_OK) { printf("\nFIFO accel frames requested : %d \n", accel_frame_length); /* Parse the FIFO data to extract accelerometer data from the FIFO buffer. */ rslt = bmi2_extract_accel(fifo_accel_data, &accel_frame_length, &fifoframe, &bmi2); printf("\nFIFO accel frames extracted : %d \n", accel_frame_length); printf("\nFIFO gyro frames requested : %d \n", gyro_frame_length); /* Parse the FIFO data to extract gyro data from the FIFO buffer. */ rslt = bmi2_extract_gyro(fifo_gyro_data, &gyro_frame_length, &fifoframe, &bmi2); printf("\nFIFO gyro frames extracted : %d \n", gyro_frame_length); printf("\nExtracted accel frames\n"); /* Print the parsed accelerometer data from the FIFO buffer. for (index = 0; index < accel_frame_length; index++) { printf("ACCEL[%d] X : %d\t Y : %d\t Z : %d\n", index, fifo_accel_data[index].x, fifo_accel_data[index].y, fifo_accel_data[index].z); } printf("\nExtracted gyro frames\n"); for (index = 0; index < gyro_frame_length; index++) { printf("GYRO[%d] X : %d\t Y : %d\t Z : %d\n", index, fifo_gyro_data[index].x, fifo_gyro_data[index].y, fifo_gyro_data[index].z); } */ } // try++; }   ... View more

Hello SterlingMinsha , thank you in advance. Meanwhile, I tried another, better damper with 3 Hz resonance frequency (instead of previous 11 Hz). Also, I found Cross Axis Sensetivity being about 2% instead of 0.2% in datasheet, onto Y axis so Gyroscope Data Post Processing described in part 4.6 of datasheet would not help, as I understand. Also, I found a too big influence of a static tilt around X and Z axis onto Y axis gyro readings, about ten times more than I estimate in thery. All that I tried to compensate in software, adjusting coefficients experimentally. Now results are substantially better, but I still have about 0.5 deg error (random) of angular position (angular speed integrated) after a couple of seconds of a pretty slow movement and that is still too much for me. Also I discovered errors are about 2 times less when I suspend the experimental bench on strings instead of moving on the table. In the last case there is no vibrations from friction and movements are smoother. I would appretiate very much any data what precision of angular position and speed was achieved in reality, for slow movements. My goal is to achieve about 5 cm/sec velosity error after couple of seconds of movement at about 10 cm/sec and 10 deg/sec, little vibrations. And I got doubt if it is possible for BMI270. ... View more