diff --git a/libraries/AP_Baro/AP_Baro.cpp b/libraries/AP_Baro/AP_Baro.cpp
index 53a8743c21..aa30482eeb 100644
--- a/libraries/AP_Baro/AP_Baro.cpp
+++ b/libraries/AP_Baro/AP_Baro.cpp
@@ -100,11 +100,11 @@ void AP_Baro::calibrate()
     // the MS5611 reads quite a long way off for the first second,
     // leading to about 1m of error if we don't wait
     for (uint8_t i = 0; i < 10; i++) {
-        uint32_t tstart = hal.scheduler->millis();
+        uint32_t tstart = AP_HAL::millis();
         do {
             update();
-            if (hal.scheduler->millis() - tstart > 500) {
-                hal.scheduler->panic("PANIC: AP_Baro::read unsuccessful "
+            if (AP_HAL::millis() - tstart > 500) {
+                AP_HAL::panic("PANIC: AP_Baro::read unsuccessful "
                         "for more than 500ms in AP_Baro::calibrate [2]\r\n");
             }
             hal.scheduler->delay(10);
@@ -120,11 +120,11 @@ void AP_Baro::calibrate()
     const uint8_t num_samples = 5;
 
     for (uint8_t c = 0; c < num_samples; c++) {
-        uint32_t tstart = hal.scheduler->millis();
+        uint32_t tstart = AP_HAL::millis();
         do {
             update();
-            if (hal.scheduler->millis() - tstart > 500) {
-                hal.scheduler->panic("PANIC: AP_Baro::read unsuccessful "
+            if (AP_HAL::millis() - tstart > 500) {
+                AP_HAL::panic("PANIC: AP_Baro::read unsuccessful "
                         "for more than 500ms in AP_Baro::calibrate [3]\r\n");
             }
         } while (!healthy());
@@ -152,7 +152,7 @@ void AP_Baro::calibrate()
             return;
         }
     }
-    hal.scheduler->panic("AP_Baro: all sensors uncalibrated");
+    AP_HAL::panic("AP_Baro: all sensors uncalibrated");
 }
 
 /*
@@ -170,7 +170,7 @@ void AP_Baro::update_calibration()
         sensors[i].ground_temperature.set(get_calibration_temperature(i));
 
         // don't notify the GCS too rapidly or we flood the link
-        uint32_t now = hal.scheduler->millis();
+        uint32_t now = AP_HAL::millis();
         if (now - _last_notify_ms > 10000) {
             sensors[i].ground_pressure.notify();
             sensors[i].ground_temperature.notify();
@@ -245,7 +245,7 @@ float AP_Baro::get_climb_rate(void)
 void AP_Baro::set_external_temperature(float temperature)
 {
     _external_temperature = temperature;
-    _last_external_temperature_ms = hal.scheduler->millis();
+    _last_external_temperature_ms = AP_HAL::millis();
 }
 
 /*
@@ -254,7 +254,7 @@ void AP_Baro::set_external_temperature(float temperature)
 float AP_Baro::get_calibration_temperature(uint8_t instance) const
 {
     // if we have a recent external temperature then use it
-    if (_last_external_temperature_ms != 0 && hal.scheduler->millis() - _last_external_temperature_ms < 10000) {
+    if (_last_external_temperature_ms != 0 && AP_HAL::millis() - _last_external_temperature_ms < 10000) {
         return _external_temperature;
     }
     // if we don't have an external temperature then use the minimum
@@ -324,7 +324,7 @@ void AP_Baro::init(void)
     }
 #endif
     if (_num_drivers == 0 || _num_sensors == 0 || drivers[0] == NULL) {
-        hal.scheduler->panic("Baro: unable to initialise driver");
+        AP_HAL::panic("Baro: unable to initialise driver");
     }
 }
 
@@ -342,7 +342,7 @@ void AP_Baro::update(void)
 
     // consider a sensor as healthy if it has had an update in the
     // last 0.5 seconds
-    uint32_t now = hal.scheduler->millis();
+    uint32_t now = AP_HAL::millis();
     for (uint8_t i=0; i<_num_sensors; i++) {
         sensors[i].healthy = (now - sensors[i].last_update_ms < 500) && !is_zero(sensors[i].pressure);
     }
@@ -398,7 +398,7 @@ void AP_Baro::accumulate(void)
 uint8_t AP_Baro::register_sensor(void)
 {
     if (_num_sensors >= BARO_MAX_INSTANCES) {
-        hal.scheduler->panic("Too many barometers");
+        AP_HAL::panic("Too many barometers");
     }
     return _num_sensors++;
 }
diff --git a/libraries/AP_Baro/AP_Baro_BMP085.cpp b/libraries/AP_Baro/AP_Baro_BMP085.cpp
index 502d4801b7..8343bfcb65 100644
--- a/libraries/AP_Baro/AP_Baro_BMP085.cpp
+++ b/libraries/AP_Baro/AP_Baro_BMP085.cpp
@@ -35,7 +35,7 @@ extern const AP_HAL::HAL& hal;
 // Temp conversion time is 4.5ms
 // Pressure conversion time is 25.5ms (for OVERSAMPLING=3)
 #define BMP085_EOC -1
-#define BMP_DATA_READY() (BMP085_State == 0 ? hal.scheduler->millis() > (_last_temp_read_command_time + 5) : hal.scheduler->millis() > (_last_press_read_command_time + 26))
+#define BMP_DATA_READY() (BMP085_State == 0 ? AP_HAL::millis() > (_last_temp_read_command_time + 5) : AP_HAL::millis() > (_last_press_read_command_time + 26))
 #else
 #define BMP_DATA_READY() hal.gpio->read(BMP085_EOC)
 #endif
@@ -64,7 +64,7 @@ AP_Baro_BMP085::AP_Baro_BMP085(AP_Baro &baro) :
 
     // take i2c bus sempahore
     if (!i2c_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
-        hal.scheduler->panic("BMP085: unable to get semaphore");
+        AP_HAL::panic("BMP085: unable to get semaphore");
     }
 
     // End Of Conversion (PC7) input
@@ -74,7 +74,7 @@ AP_Baro_BMP085::AP_Baro_BMP085(AP_Baro &baro) :
 
     // We read the calibration data registers
     if (hal.i2c->readRegisters(BMP085_ADDRESS, 0xAA, 22, buff) != 0) {
-        hal.scheduler->panic("BMP085: bad calibration registers");
+        AP_HAL::panic("BMP085: bad calibration registers");
     }
 
     ac1 = ((int16_t)buff[0] << 8) | buff[1];
@@ -164,7 +164,7 @@ void AP_Baro_BMP085::Command_ReadPress()
     // Mode 0x34+(OVERSAMPLING << 6) is osrs=3 when OVERSAMPLING=3 => 25.5ms conversion time
     hal.i2c->writeRegister(BMP085_ADDRESS, 0xF4,
                            0x34+(OVERSAMPLING << 6));
-    _last_press_read_command_time = hal.scheduler->millis();
+    _last_press_read_command_time = AP_HAL::millis();
 }
 
 // Read Raw Pressure values
@@ -173,7 +173,7 @@ bool AP_Baro_BMP085::ReadPress()
     uint8_t buf[3];
 
     if (hal.i2c->readRegisters(BMP085_ADDRESS, 0xF6, 3, buf) != 0) {
-        _retry_time = hal.scheduler->millis() + 1000;
+        _retry_time = AP_HAL::millis() + 1000;
         hal.i2c->setHighSpeed(false);
         return false;
     }
@@ -188,7 +188,7 @@ bool AP_Baro_BMP085::ReadPress()
 void AP_Baro_BMP085::Command_ReadTemp()
 {
     hal.i2c->writeRegister(BMP085_ADDRESS, 0xF4, 0x2E);
-    _last_temp_read_command_time = hal.scheduler->millis();
+    _last_temp_read_command_time = AP_HAL::millis();
 }
 
 // Read Raw Temperature values
diff --git a/libraries/AP_Baro/AP_Baro_Backend.cpp b/libraries/AP_Baro/AP_Baro_Backend.cpp
index 2d165206fd..ae662457b8 100644
--- a/libraries/AP_Baro/AP_Baro_Backend.cpp
+++ b/libraries/AP_Baro/AP_Baro_Backend.cpp
@@ -19,5 +19,5 @@ void AP_Baro_Backend::_copy_to_frontend(uint8_t instance, float pressure, float
     }
     _frontend.sensors[instance].pressure = pressure;
     _frontend.sensors[instance].temperature = temperature;
-    _frontend.sensors[instance].last_update_ms = hal.scheduler->millis();
+    _frontend.sensors[instance].last_update_ms = AP_HAL::millis();
 }
diff --git a/libraries/AP_Baro/AP_Baro_MS5611.cpp b/libraries/AP_Baro/AP_Baro_MS5611.cpp
index b8e08c5712..543ffc2e1f 100644
--- a/libraries/AP_Baro/AP_Baro_MS5611.cpp
+++ b/libraries/AP_Baro/AP_Baro_MS5611.cpp
@@ -69,11 +69,11 @@ void AP_SerialBus_SPI::init()
 {
     _spi = hal.spi->device(_device);
     if (_spi == NULL) {
-        hal.scheduler->panic("did not get valid SPI device driver!");
+        AP_HAL::panic("did not get valid SPI device driver!");
     }
     _spi_sem = _spi->get_semaphore();
     if (_spi_sem == NULL) {
-        hal.scheduler->panic("AP_SerialBus_SPI did not get valid SPI semaphroe!");
+        AP_HAL::panic("AP_SerialBus_SPI did not get valid SPI semaphroe!");
     }
     _spi->set_bus_speed(_speed);
 }
@@ -129,7 +129,7 @@ void AP_SerialBus_I2C::init()
 {
     _i2c_sem = _i2c->get_semaphore();
     if (_i2c_sem == NULL) {
-        hal.scheduler->panic("AP_SerialBus_I2C did not get valid I2C semaphore!");
+        AP_HAL::panic("AP_SerialBus_I2C did not get valid I2C semaphore!");
     }
 }
 
@@ -192,7 +192,7 @@ AP_Baro_MS56XX::AP_Baro_MS56XX(AP_Baro &baro, AP_SerialBus *serial, bool use_tim
     hal.scheduler->suspend_timer_procs();
 
     if (!_serial->sem_take_blocking()){
-        hal.scheduler->panic("PANIC: AP_Baro_MS56XX: failed to take serial semaphore for init");
+        AP_HAL::panic("PANIC: AP_Baro_MS56XX: failed to take serial semaphore for init");
     }
 
     _serial->write(CMD_MS5611_RESET);
@@ -208,12 +208,12 @@ AP_Baro_MS56XX::AP_Baro_MS56XX(AP_Baro &baro, AP_SerialBus *serial, bool use_tim
     _C6 = _serial->read_16bits(CMD_MS5611_PROM_C6);
 
     if (!_check_crc()) {
-        hal.scheduler->panic("Bad CRC on MS5611");
+        AP_HAL::panic("Bad CRC on MS5611");
     }
 
     // Send a command to read Temp first
     _serial->write(ADDR_CMD_CONVERT_D2);
-    _last_timer = hal.scheduler->micros();
+    _last_timer = AP_HAL::micros();
     _state = 0;
 
     _s_D1 = 0;
@@ -286,7 +286,7 @@ bool AP_Baro_MS56XX::_check_crc(void)
 void AP_Baro_MS56XX::_timer(void)
 {
     // Throttle read rate to 100hz maximum.
-    if (hal.scheduler->micros() - _last_timer < 10000) {
+    if (AP_HAL::micros() - _last_timer < 10000) {
         return;
     }
 
@@ -349,7 +349,7 @@ void AP_Baro_MS56XX::_timer(void)
         }
     }
 
-    _last_timer = hal.scheduler->micros();
+    _last_timer = AP_HAL::micros();
     _serial->sem_give();
 }