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AP_Airspeed: fixed I2C semaphore handling for I2C airspeed

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this affects MS4525DO on APM2
This commit is contained in:
Andrew Tridgell 2013-10-29 14:55:23 +11:00 committed by Randy Mackay
parent b4c8dd5a41
commit d4af757cbb
1 changed files with 18 additions and 3 deletions
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21
libraries/AP_Airspeed/AP_Airspeed_I2C.cpp
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@ -31,9 +31,17 @@ extern const AP_HAL::HAL& hal;
// probe and initialise the sensor
bool AP_Airspeed_I2C::init(void)
{
// get pointer to i2c bus semaphore
AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
// take i2c bus sempahore
if (!i2c_sem->take(200))
return false;
_measure();
hal.scheduler->delay(10);
_collect();
i2c_sem->give();
if (_last_sample_time_ms != 0) {
hal.scheduler->register_timer_process(AP_HAL_MEMBERPROC(&AP_Airspeed_I2C::_timer));
return true;
@ -45,16 +53,16 @@ bool AP_Airspeed_I2C::init(void)
void AP_Airspeed_I2C::_measure(void)
{
_measurement_started_ms = 0;
if (hal.i2c->writeRegisters(I2C_ADDRESS_MS4525DO, 0, 0, NULL) != 0) {
return;
if (hal.i2c->writeRegisters(I2C_ADDRESS_MS4525DO, 0, 0, NULL) == 0) {
_measurement_started_ms = hal.scheduler->millis();
}
_measurement_started_ms = hal.scheduler->millis();
}
// read the values from the sensor
void AP_Airspeed_I2C::_collect(void)
{
uint8_t data[4];
_measurement_started_ms = 0;
if (hal.i2c->read(I2C_ADDRESS_MS4525DO, 4, data) != 0) {
@ -82,8 +90,14 @@ void AP_Airspeed_I2C::_collect(void)
// 1kHz timer
void AP_Airspeed_I2C::_timer(void)
{
AP_HAL::Semaphore* i2c_sem = hal.i2c->get_semaphore();
if (!i2c_sem->take_nonblocking())
return;
if (_measurement_started_ms == 0) {
_measure();
i2c_sem->give();
return;
}
if ((hal.scheduler->millis() - _measurement_started_ms) > 10) {
@ -91,6 +105,7 @@ void AP_Airspeed_I2C::_timer(void)
// start a new measurement
_measure();
}
i2c_sem->give();
}
// return the current differential_pressure in Pascal