[sensor]--bmi160-Accelerometer, Gyro sensor

Recently engaged in a project related to the accelerometer, so contact with more sensors, now write a summary, to prevent the later and I like to walk so many detours.
The first thing to see is the pin graph, if the driver should not first troubleshoot the hardware problem:
SPI Connection method

IIc Connection method

We then focus on a few registers:

sensor Name (read/write)	Register number	function
Chipid (R)	0x00	The ID of the chip, generally used to see if the driver is normal, fixed value 0xd1
Pmu_status (R)	0x03	Display the current power mode of each sensor, divided into three modes normal\low_power\suspend
Acc_conf (RW)	0x40	Set the output data rate, bandwidth, and acceleration sensor read mode
Acc_range	0x41	Allowable acceleration g range of choice
Gyr_conf (RW)	0x42	Set the output data rate, bandwidth, and gyro read mode in the sensor.
Gyr_range (RW)	0x43	Defining the BMI160 angular velocity measurement range
Int_en (RW)	0x50-0x52	Enable a variety of interrupts, including acceleration data, angular velocity data and a variety of special functions of the interrupt, so that can be mapped to the INT1 on the output, you can trigger the MCU external interrupt.
Int_out_ctrl (RW)	0x53	Output control, including output enable, trigger level, edge, and output mode (push-pull and open-drain)
Int_latch (RW)	0x54	Set the interrupt latch mode (not very understand, the first is the lock, so there is no interruption of output ..., and then turn it off)
CMD (R)	0x7E	The command register triggers operations such as Softreset, NVM programming, and so on. Special such as: Start_foc, Acc_set_pmu_mode, Gyr_set_pmu_mode, Mag_set_pmu_mode, PROG_NVM, Fifo_flush, Int_reset, Softreset, step _cnt_clr

Next is a variety of special function registers, not much to say, which configuration that can be
Focus on the function of the pedometer , now also compare fire:

sensor Name (read/write)	Register number	function
Step_conf (RW)	0x7a-0x7b	Configuration of step detection, including normal mode,sensitive Mode,robust mode three can also be configured
STEP_CNT (R)	0x78-0x79	Read the number of steps directly from the two registers, note that the range is -32768--32768

The following code slice is the initialization of the step, using the stm32f405:

void Bmi160_init (void) {uint8_t ui8status = 0;
    uint8_t ui8attempts = 20;

    uint8_t device_id;
    Bmi160_spi_init ();
    kprintf ("BMI160 Init ok.\n");            Bmi160_cs=1;

    SPI chip Select Cancel//Reset the BMI160 sensor Bmi160_reset ();
    Put Accel and Gyro in normal mode. while (ui8status! = 0x20 && ui8attempts--) {Bmi160_write_reg (am_devices_bmi160_cmd, 0x12);//Set acceleration                 
      Calculated as Low_power bmi160_write_reg (Am_devices_bmi160_cmd, 0x14);//Set gyroscope suspend Delay_ms (1);
   Ui8status = Bmi160_read_reg (am_devices_bmi160_pmu_status);//read acceleration and gyroscope initialized to Low_power suspend}
    BMI160 not in correct power mode if (!ui8attempts) {return;

        } kprintf ("pmu_status:0x%x \ r \ n", ui8status); Bmi160_write_reg (Am_devices_bmi160_step_conf_0, 0x15);//Pedometer function Bmi160_write_reg (am_devices_bmi160_step_conf_1, 0x0
    B); Bmi160_write_reg (Am_devices_bmi160_acc_range, 0x05);/Set Accelerometer +-4g//Read status register to clear it.
    Ui8status = Bmi160_read_reg (Am_devices_bmi160_err_reg);//Read error status Register clear Ui8status/Enable INT 1 output as active high Bmi160_write_reg (Am_devices_bmi160_int_out_ctrl, 0x0A);//output enable INT1 pin, high active//int1 Set//Map INT1 to the Step detection Interrupt Bmi160_write_reg (am_devices_bmi160_int_map_1, 0x80);//Map INT1 to watermark interrupt//Ena BLE INT 1 as FIFO Watermark Bmi160_write_reg (am_devices_bmi160_int_en_1, 0x10);//Enable Data-ready}//Get step number void bmi160

    _getstep (short *rawstep) {uint8_t buf[2];
    buf[0]= Bmi160_read_reg (am_devices_bmi160_step_cnt_1);

    buf[1]= Bmi160_read_reg (AM_DEVICES_BMI160_STEP_CNT_0);  
*rawstep= ((uint16_t) buf[0]<<8) |buf[1]; }

SPI initialization (I started with the EEPROM SPI configuration read and write, and so on, has not been able to drive, and then suddenly found that the problem is SPI):

The following is BMI160 driver////////////////////void bmi160_spi_init (void) {Gpio_inittypedef gpio_initstructure
  ;

  Spi_inittypedef spi_initstructure; Rcc_ahb1periphclockcmd (Rcc_ahb1periph_gpioa, enable);//enable Gpioa clock Rcc_apb2periphclockcmd (RCC_APB2PERIPH_SPI1, enable); SPI1 clock//GPIOF9,F10 initialization setting Gpio_initstructure.gpio_pin = gpio_pin_5| gpio_pin_6| Gpio_pin_7;//pb3~5 multiplexing function Output Gpio_initstructure.gpio_mode = gpio_mode_af;//multiplexing function Gpio_initstructure.gpio_otype = GPIO_OTy pe_pp;//push-Pull output gpio_initstructure.gpio_speed = Gpio_speed_50mhz;//100mhz GPIO_INITSTRUCTURE.GPIO_PUPD = GPIO_PuPd_UP;/ /Pull Gpio_init (Gpioa, &gpio_initstructure);//Initialize Gpio_pinafconfig (GPIOA,GPIO_PINSOURCE5,GPIO_AF_SPI1); PI1 for SPI1 gpio_pinafconfig (GPIOA,GPIO_PINSOURCE6,GPIO_AF_SPI1); PI2 for SPI1 gpio_pinafconfig (GPIOA,GPIO_PINSOURCE7,GPIO_AF_SPI1); PI3 multiplexing for SPI1//Here only for SPI Port initialization rcc_apb2periphresetcmd (rcc_apb2periph_spi1,enable);//Reset SPI1 Rcc_apb2periphreset CMD (Rcc_apb2periph_spi1,disable);//Stop Reset SPI1 spi_i2s_deinit (SPI1);  Spi_initstructure.spi_direction = Spi_direction_2lines_fullduplex;       Set SPI unidirectional or bidirectional data mode: SPI set to double-line bidirectional full duplex spi_initstructure.spi_mode = Spi_mode_master;       Set SPI operating mode: set to primary SPI spi_initstructure.spi_datasize = spi_datasize_8b;     Set the data size of the SPI: SPI send receive 8-bit frame structure Spi_initstructure.spi_cpol = Spi_cpol_high;    The idle state of the serial Sync clock is high spi_initstructure.spi_cpha = Spi_cpha_2edge;       The second hop edge (up or down) data of the serial synchronization clock is sampled spi_initstructure.spi_nss = Spi_nss_soft; NSS signals are managed by hardware (NSS pins) or software (using SSI bits): internal NSS signal with SSI bit control Spi_initstructure.spi_baudrateprescaler = spi_baudrateprescaler_64     ;  Defines the value of the baud rate Prescaler: The baud rate prescaler value is Spi_initstructure.spi_firstbit = SPI_FIRSTBIT_MSB;    Specifies whether the data transfer begins with the MSB bit or the LSB bit: The data transfer begins with the MSB bit spi_initstructure.spi_crcpolynomial = 7;  Polynomial spi_init of CRC value calculation (SPI1, &spi_initstructure); Initializes the peripheral Spix register spi_cmd (SPI1, ENABLE) based on the parameters specified in the spi_initstruct; Enable SPI peripheral spi1_readwritebyte (0xff);//Start transmission}//spi1 SpeedDegree set function//spi speed =fapb2/divide factor//@ref spi_baudrate_prescaler:spi_baudrateprescaler_2~spi_baudrateprescaler_256// The fAPB2 clock is generally 84mhz:void spi1_setspeed (U8 spi_baudrateprescaler) {Assert_param (Is_spi_baudrate_prescaler (SPI_   Baudrateprescaler));//validity spi1->cr1&=0xffc7;//bit 3-5 cleared to set the baud rate spi1->cr1|=spi_baudrateprescaler; Set SPI1 speed Spi_cmd (spi1,enable); Enable SPI1}//spi1 read and write a byte//txdata: bytes to write//return value: bytes read U8 spi1_readwritebyte (U8 txdata) {U8 Result,retry=0;//result: return Back to SPI Read and write results;
        Retry: Failed retry count while (Spi_i2s_getflagstatus (SPI1,SPI_I2S_FLAG_TXE) ==reset) {retry++;
    if (retry>200) return 0;
    } spi_i2s_senddata (SPI1, TxData);
        while (Spi_i2s_getflagstatus (spi1,spi_i2s_flag_rxne) ==reset) {retry++;
    if (retry>200) return 0;
    } return Spi_i2s_receivedata (SPI1);
Spi_i2s_clearflag (SPI1,SPI_I2S_FLAG_RXNE);     
  }//Read SPI Register value//reg: Register to read U8 Bmi160_read_reg (U8 reg) {U8 reg_val;     Bmi160_cs = 0;     Enable SPI to transmit Delay_ms (1);   Spi1_readwritebyte (reg|0x80); 1. Send register number//ored with "read request" bit reg_val=spi1_readwritebyte (0XFF);//Read register contents//Send a value of 0 to read the F  
    Irst byte Returned:delay_ms (1);          Bmi160_cs = 1;           Disable SPI transmission return (REG_VAL);  
  Return status Value}//SPI write register//reg: Specify register Address//value: Write value U8 bmi160_write_reg (U8 reg,u8 value) {U8 status;                 bmi160_cs=0;      Enable SPI to transmit status =spi1_readwritebyte (reg&0x7f);//2. Send register number Spi1_readwritebyte (value);                 The value of the write register is Bmi160_cs=1;                   Disable SPI transmission return (status); Return status Value}