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建立网站的英文短语,如何提高网站开发效率,wordpress suxing,优秀网站有哪些接前一篇文章#xff1a;ICM20948 DMP代码详解#xff08;14#xff09; 上一回开始对icm20948_sensor_setup函数中第3段代码即inv_icm20948_initialize函数进行解析。为了便于理解和回顾#xff0c;再次贴出其源码#xff0c;在EMD-Core\sources\Invn\Devices\Drivers\IC…接前一篇文章ICM20948 DMP代码详解14 上一回开始对icm20948_sensor_setup函数中第3段代码即inv_icm20948_initialize函数进行解析。为了便于理解和回顾再次贴出其源码在EMD-Core\sources\Invn\Devices\Drivers\ICM20948\Icm20948Setup.c中如下 int inv_icm20948_initialize(struct inv_icm20948 * s, const uint8_t dmp3_image, uint32_t dmp3_image_size) {if(s-serif.is_spi) {/ Hardware initialization /// No image to be loaded from flash, no pointer to pass.if (inv_icm20948_initialize_lower_driver(s, SERIAL_INTERFACE_SPI, dmp3_image, dmp3_image_size)) {return -1;}}else {/ Hardware initialization */// No image to be loaded from flash, no pointer to pass.if (inv_icm20948_initialize_lower_driver(s, SERIAL_INTERFACE_I2C, dmp3_image, dmp3_image_size)) {return -1;}}return 0; } 该函数主要是调用了inv_icm20948_initialize_lower_driver其在EMD-Core\sources\Invn\Devices\Drivers\ICM20948\Icm20948DataBaseDriver.c中代码如下 /** Should be called once on power up. Loads DMP3, initializes internal variables needed

• for other lower driver functions. */ int inv_icm20948_initialize_lower_driver(struct inv_icm20948 *s, enum SMARTSENSOR_SERIAL_INTERFACE type, const uint8_t dmp3_image, uint32_t dmp3_image_size) {int result 0;static unsigned char data;// set static variables-sAllowLpEn 1;s-s_compass_available 0;// ICM20948 do not support the proximity sensor for the moment.// s_proximity_available variable is nerver changess-s_proximity_available 0;// Set varialbes to default valuesmemset(s-base_state, 0, sizeof(s-base_state));s-base_state.pwr_mgmt_1 BIT_CLK_PLL;s-base_state.pwr_mgmt_2 BIT_PWR_ACCEL_STBY | BIT_PWR_GYRO_STBY | BIT_PWR_PRESSURE_STBY;s-base_state.serial_interface type;result | inv_icm20948_read_mems_reg(s, REG_USER_CTRL, 1, s-base_state.user_ctrl);result | inv_icm20948_wakeup_mems(s);result | inv_icm20948_read_mems_reg(s, REG_WHO_AM_I, 1, data);/ secondary cycle mode should be set all the time */data BIT_I2C_MST_CYCLE|BIT_ACCEL_CYCLE|BIT_GYRO_CYCLE;// Set default mode to low power moderesult | inv_icm20948_set_lowpower_or_highperformance(s, 0);// Disable Ivory DMP.if(s-base_state.serial_interface SERIAL_INTERFACE_SPI) s-base_state.user_ctrl BIT_I2C_IF_DIS;elses-base_state.user_ctrl 0;result | inv_icm20948_write_single_mems_reg(s, REG_USER_CTRL, s-base_state.user_ctrl);//Setup Ivory DMP.result | inv_icm20948_load_firmware(s, dmp3_image, dmp3_image_size);if(result)return result;elses-base_state.firmware_loaded 1;result | inv_icm20948_set_dmp_address(s);// Turn off all sensors on DMP by default.//result | dmp_set_data_output_control1(0); // FIXME in DMP, these should be off by default.result | dmp_icm20948_reset_control_registers(s);// set FIFO watermark to 80% of actual FIFO sizeresult | dmp_icm20948_set_FIFO_watermark(s, 800);// Enable Interrupts.data 0x2;result | inv_icm20948_write_mems_reg(s, REG_INT_ENABLE, 1, data); // Enable DMP Interruptdata 0x1;result | inv_icm20948_write_mems_reg(s, REG_INT_ENABLE_2, 1, data); // Enable FIFO Overflow Interrupt// TRACKING : To have accelerometers datas and the interrupt without gyro enables.data 0XE4;result | inv_icm20948_write_mems_reg(s, REG_SINGLE_FIFO_PRIORITY_SEL, 1, data);// Disable HW temp fixinv_icm20948_read_mems_reg(s, REG_HW_FIX_DISABLE,1,data);data | 0x08;inv_icm20948_write_mems_reg(s, REG_HW_FIX_DISABLE,1,data);// Setup MEMs properties.s-base_state.accel_averaging 1; //Change this value if higher sensor sample avergaing is required.s-base_state.gyro_averaging 1; //Change this value if higher sensor sample avergaing is required.inv_icm20948_set_gyro_divider(s, FIFO_DIVIDER); //Initial sampling rate 1125Hz/191 56Hz.inv_icm20948_set_accel_divider(s, FIFO_DIVIDER); //Initial sampling rate 1125Hz/191 56Hz.// Init the sample rate to 56 Hz for BAC,STEPC and B2Sdmp_icm20948_set_bac_rate(s, DMP_ALGO_FREQ_56);dmp_icm20948_set_b2s_rate(s, DMP_ALGO_FREQ_56);// FIFO Setup.result | inv_icm20948_write_single_mems_reg(s, REG_FIFO_CFG, BIT_SINGLE_FIFO_CFG); // FIFO Config. fixme do once? burst write?result | inv_icm20948_write_single_mems_reg(s, REG_FIFO_RST, 0x1f); // Reset all FIFOs.result | inv_icm20948_write_single_mems_reg(s, REG_FIFO_RST, 0x1e); // Keep all but Gyro FIFO in reset.result | inv_icm20948_write_single_mems_reg(s, REG_FIFO_EN, 0x0); // Slave FIFO turned off.result | inv_icm20948_write_single_mems_reg(s, REG_FIFO_EN_2, 0x0); // Hardware FIFO turned off.s-base_state.lp_en_support 1;if(s-base_state.lp_en_support 1)inv_icm20948_set_chip_power_state(s, CHIP_LP_ENABLE, 1);result | inv_icm20948_sleep_mems(s); return result; } 上一回讲了函数一开始的成员设置本回继续往下对该函数进行解析。当前来到以下代码片段 result | inv_icm20948_read_mems_reg(s, REG_USER_CTRL, 1, s-base_state.user_ctrl); inv_icm20948_read_mems_reg函数在EMD-Core\sources\Invn\Devices\Drivers\ICM20948\Icm20948Transport.c中代码如下 /**
• brief Read data from a register on MEMs.
• param[in] Register address
• param[in] Length of data
• param[in] Data to be written
• return 0 if successful. */ int inv_icm20948_read_mems_reg(struct inv_icm20948 *s, uint16_t reg, unsigned int length, unsigned char *data) {int result 0;unsigned int bytesRead 0;unsigned char regOnly (unsigned char)(reg 0x7F);unsigned char i, dat[INV_MAX_SERIAL_READ];unsigned char power_state inv_icm20948_get_chip_power_state(s);if((power_state CHIP_AWAKE) 0) // Wake up chip since it is asleepresult inv_icm20948_set_chip_power_state(s, CHIP_AWAKE, 1);if(check_reg_access_lp_disable(s, reg)) // Check if register needs LP_EN to be disabledresult | inv_icm20948_set_chip_power_state(s, CHIP_LP_ENABLE, 0); //Disable LP_ENresult | inv_set_bank(s, reg 7);while (bytesReadlength) {int thisLen min(INV_MAX_SERIAL_READ, length-bytesRead);if(s-base_state.serial_interface SERIAL_INTERFACE_SPI) {result | inv_icm20948_read_reg(s, regOnlybytesRead, dat[bytesRead], thisLen);} else {result | inv_icm20948_read_reg(s, regOnlybytesRead, data[bytesRead],thisLen);}if (result)return result;bytesRead thisLen;}if(s-base_state.serial_interface SERIAL_INTERFACE_SPI) {for (i0; i length; i) {data dat[i];data;}}if(check_reg_access_lp_disable(s, reg)) // Check if register needs LP_EN to be enabled result | inv_icm20948_set_chip_power_state(s, CHIP_LP_ENABLE, 1); //Enable LP_ENreturn result; }要弄懂这个函数必须先弄清楚其中的几个函数。一个一个来看。 1inv_icm20948_get_chip_power_state函数 inv_icm20948_get_chip_power_state函数在EMD-Core\sources\Invn\Devices\Drivers\ICM20948\Icm20948DataBaseDriver.c中代码如下 /!******************************************************************************* return Current wake status of the Ivory chip.*****************************************************************************/ uint8_t inv_icm20948_get_chip_power_state(struct inv_icm20948 s) {return s-base_state.wake_state; } 其实就是得到s-base_state.wake_state的值。前文书中曾讲到在inv_icm20948_initialize_lower_driver函数中对于s-base_state整个进行了清零因此这时的值必然是0。 2inv_icm20948_set_chip_power_state函数 inv_icm20948_set_chip_power_state函数也是在EMD-Core\sources\Invn\Devices\Drivers\ICM20948\Icm20948DataBaseDriver.c中代码如下 /!***************************************************************************** brief This function sets the power state of the Ivory chip * loop* param[in] Function - CHIP_AWAKE, CHIP_LP_ENABLE* param[in] On/Off - The functions are enabled if previously disabled and disabled if previously enabled based on the value of On/Off.*******************************************************************************/ int inv_icm20948_set_chip_power_state(struct inv_icm20948 *s, unsigned char func, unsigned char on_off) {int status 0;switch(func) {case CHIP_AWAKE: if(on_off){if((s-base_state.wake_state CHIP_AWAKE) 0) {// undo sleep_ens-base_state.pwr_mgmt_1 ~BIT_SLEEP;status inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state | CHIP_AWAKE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}} else {if(s-base_state.wake_state CHIP_AWAKE) {// set sleep_ens-base_state.pwr_mgmt_1 | BIT_SLEEP;status inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state ~CHIP_AWAKE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}}break;case CHIP_LP_ENABLE:if(s-base_state.lp_en_support 1) {if(on_off) {if( (inv_icm20948_get_lpen_control(s)) ((s-base_state.wake_state CHIP_LP_ENABLE) 0)){s-base_state.pwr_mgmt_1 | BIT_LP_EN; // lp_en ONstatus inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state | CHIP_LP_ENABLE;}} else {if(s-base_state.wake_state CHIP_LP_ENABLE){s-base_state.pwr_mgmt_1 ~BIT_LP_EN; // lp_en offstatus inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state ~CHIP_LP_ENABLE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}}}break;default:break;}// end switchreturn status; } 这要结合inv_icm20948_read_mems_reg函数中的调用来看代码片段如下 if((power_state CHIP_AWAKE) 0) // Wake up chip since it is asleepresult inv_icm20948_set_chip_power_state(s, CHIP_AWAKE, 1);if(check_reg_access_lp_disable(s, reg)) // Check if register needs LP_EN to be disabledresult | inv_icm20948_set_chip_power_state(s, CHIP_LP_ENABLE, 0); //Disable LP_EN 一共两次调用一次是CHIP_AWAKE另一次是CHIP_LP_ENABLE。正好对应inv_icm20948_set_chip_power_state函数中switch的两个case。依次看一下这两个分支 1case CHIP_AWAKE 相应代码片段如下 case CHIP_AWAKE: if(on_off){if((s-base_state.wake_state CHIP_AWAKE) 0) {// undo sleep_ens-base_state.pwr_mgmt_1 ~BIT_SLEEP;status inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state | CHIP_AWAKE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}} else {if(s-base_state.wake_state CHIP_AWAKE) {// set sleep_ens-base_state.pwr_mgmt_1 | BIT_SLEEP;status inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state ~CHIP_AWAKE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}}break; 如果inv_icm20948_set_chip_power_state函数的第3个参数unsigned char on_off传入的值为1同时状态与本次设置不同则清除s-base_state.pwr_mgmt_1中的BIT_SLEEP位写入ICM20948的REG_PWR_MGMT_1寄存器之后将s-base_state.wake_state中的CHIP_AWAKE置位并延时100us。 如果on_off传入的值为0同时状态与本次设置不同则置位s-base_state.pwr_mgmt_1中的BIT_SLEEP位写入ICM20948的REG_PWR_MGMT_1寄存器之后清除s-base_state.wake_state中的CHIP_AWAKE位并延时100us。 2case CHIP_LP_ENABLE 相应代码片段如下 case CHIP_LP_ENABLE:if(s-base_state.lp_en_support 1) {if(on_off) {if( (inv_icm20948_get_lpen_control(s)) ((s-base_state.wake_state CHIP_LP_ENABLE) 0)){s-base_state.pwr_mgmt_1 | BIT_LP_EN; // lp_en ONstatus inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state | CHIP_LP_ENABLE;}} else {if(s-base_state.wake_state CHIP_LP_ENABLE){s-base_state.pwr_mgmt_1 ~BIT_LP_EN; // lp_en offstatus inv_icm20948_write_single_mems_reg_core(s, REG_PWR_MGMT_1, s-base_state.pwr_mgmt_1);s-base_state.wake_state ~CHIP_LP_ENABLE;inv_icm20948_sleep_100us(1); // after writing the bit wait 100 Micro Seconds}}}break; 在s-base_state.lp_en_support设置的情况下判断体代码才有效。此时并未设置过还是之前在inv_icm20948_initialize_lower_driver函数中设置的清零状态。 不过这里也先解析一下免得以后还得回来再解析。 如果inv_icm20948_set_chip_power_state函数的第3个参数unsigned char on_off传入的值为1同时状态与本次设置不同则置位s-base_state.pwr_mgmt_1中的BIT_LP_EN位写入ICM20948的REG_PWR_MGMT_1寄存器之后将s-base_state.wake_state中的CHIP_LP_ENABLE置位并延时100us。 如果on_off传入的值为0同时状态与本次设置不同则清除s-base_state.pwr_mgmt_1中的BIT_LP_EN位写入ICM20948的REG_PWR_MGMT_1寄存器之后清除s-base_state.wake_state中的CHIP_LP_ENABLE位并延时100us。 inv_icm20948_set_chip_power_state函数中还有三个函数要讲一下分别是 1inv_icm20948_write_single_mems_reg_core函数 2inv_icm20948_get_lpen_control函数 3inv_icm20948_sleep_100us函数 对于这三个函数的解析请看下回。