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InertialSensor: latch the data ready pin high on new data 

this ensures we don't miss a sample due to another source of delay
This commit is contained in:
Andrew Tridgell 2012-12-23 17:46:36 +11:00
parent fcb09c3993
commit 44ad850542
1 changed files with 6 additions and 2 deletions
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8
libraries/AP_InertialSensor/AP_InertialSensor_MPU6000.cpp
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@ -54,6 +54,7 @@ extern const AP_HAL::HAL& hal;
#define MPUREG_FIFO_EN 0x23 #define MPUREG_FIFO_EN 0x23
#define MPUREG_INT_PIN_CFG 0x37 #define MPUREG_INT_PIN_CFG 0x37
# define BIT_INT_RD_CLEAR 0x10 // clear the interrupt when any read occurs # define BIT_INT_RD_CLEAR 0x10 // clear the interrupt when any read occurs
# define BIT_LATCH_INT_EN 0x20 // latch data ready pin
#define MPUREG_INT_ENABLE 0x38 #define MPUREG_INT_ENABLE 0x38
// bit definitions for MPUREG_INT_ENABLE // bit definitions for MPUREG_INT_ENABLE
# define BIT_RAW_RDY_EN 0x01 # define BIT_RAW_RDY_EN 0x01
@ -470,7 +471,10 @@ void AP_InertialSensor_MPU6000::hardware_init(Sample_rate sample_rate)
register_write(MPUREG_INT_ENABLE, BIT_RAW_RDY_EN); // configure interrupt to fire when new data arrives register_write(MPUREG_INT_ENABLE, BIT_RAW_RDY_EN); // configure interrupt to fire when new data arrives
hal.scheduler->delay(1); hal.scheduler->delay(1);
register_write(MPUREG_INT_PIN_CFG, BIT_INT_RD_CLEAR); // clear interrupt on any read
// clear interrupt on any read, and hold the data ready pin high
// until we clear the interrupt
register_write(MPUREG_INT_PIN_CFG, BIT_INT_RD_CLEAR | BIT_LATCH_INT_EN);
hal.scheduler->delay(1); hal.scheduler->delay(1);
/* Pin 70 defined especially to hook /* Pin 70 defined especially to hook
@ -497,7 +501,7 @@ float AP_InertialSensor_MPU6000::get_gyro_drift_rate(void)
uint16_t AP_InertialSensor_MPU6000::num_samples_available() uint16_t AP_InertialSensor_MPU6000::num_samples_available()
{ {
if (_drdy_pin->read()) { if (_drdy_pin->read()) {
// a data interrupt has occurred - read the data. // data is available from the MPU6000 - read the data.
// Note that doing it this way means we doing the read out of // Note that doing it this way means we doing the read out of
// interrupt context, called from the main loop. This avoids // interrupt context, called from the main loop. This avoids
// all possible conflicts with the DataFlash SPI bus // all possible conflicts with the DataFlash SPI bus