diff --git a/libraries/AP_ADC/AP_ADC_ADS1115.cpp b/libraries/AP_ADC/AP_ADC_ADS1115.cpp
index 68ec2f82eb..6cbf60f6f5 100644
--- a/libraries/AP_ADC/AP_ADC_ADS1115.cpp
+++ b/libraries/AP_ADC/AP_ADC_ADS1115.cpp
@@ -7,7 +7,9 @@
 #define ADS1115_ADDRESS_ADDR_VDD    0x49 // address pin high (VCC)
 #define ADS1115_ADDRESS_ADDR_SDA    0x4A // address pin tied to SDA pin
 #define ADS1115_ADDRESS_ADDR_SCL    0x4B // address pin tied to SCL pin
-#define ADS1115_DEFAULT_ADDRESS     ADS1115_ADDRESS_ADDR_GND
+
+#define ADS1115_I2C_ADDR            ADS1115_ADDRESS_ADDR_GND
+#define ADS1115_I2C_BUS             1
 
 #define ADS1115_RA_CONVERSION       0x00
 #define ADS1115_RA_CONFIG           0x01
@@ -106,9 +108,9 @@ static const uint16_t mux_table[ADS1115_CHANNELS_COUNT] = {
 };
 
 
-AP_ADC_ADS1115::AP_ADC_ADS1115():
-    _dev(hal.i2c_mgr->get_device(0, ADS1115_DEFAULT_ADDRESS)),
-    _channel_to_read(0)
+AP_ADC_ADS1115::AP_ADC_ADS1115()
+    : _dev(hal.i2c_mgr->get_device(ADS1115_I2C_BUS, ADS1115_I2C_ADDR))
+    , _channel_to_read(0)
 {
     _samples = new adc_report_s[_channels_number];
 }
@@ -127,22 +129,17 @@ bool AP_ADC_ADS1115::init()
 
 bool AP_ADC_ADS1115::_start_conversion(uint8_t channel)
 {
-    struct {
+    struct PACKED {
         uint8_t reg;
-        uint16_t w;
+        be16_t val;
     } config;
 
-    config.w = ADS1115_OS_ACTIVE | _gain | mux_table[channel] |
-    ADS1115_MODE_SINGLESHOT | ADS1115_COMP_QUE_DISABLE | ADS1115_RATE_250;
-
     config.reg = ADS1115_RA_CONFIG;
-    config.w = htobe16(config.w);
+    config.val = htobe16(ADS1115_OS_ACTIVE | _gain | mux_table[channel] |
+                         ADS1115_MODE_SINGLESHOT | ADS1115_COMP_QUE_DISABLE |
+                         ADS1115_RATE_250);
 
-    if (_dev->transfer((uint8_t *)&config, sizeof(config), nullptr, 0)) {
-        return false;
-    }
-
-    return true;
+    return _dev->transfer((uint8_t *)&config, sizeof(config), nullptr, 0);
 }
 
 size_t AP_ADC_ADS1115::read(adc_report_s *report, size_t length) const
@@ -202,32 +199,32 @@ void AP_ADC_ADS1115::_update()
         return;
     }
 
-    uint16_t word, config;
+    uint8_t config[2];
+    be16_t val;
 
     if (!_dev->get_semaphore()->take_nonblocking()) {
         return;
     }
 
-    if (!_dev->read_registers(ADS1115_RA_CONFIG, (uint8_t *)&config, sizeof(config))) {
+    if (!_dev->read_registers(ADS1115_RA_CONFIG, config, sizeof(config))) {
         error("i2c->read_registers failed in ADS1115");
         _dev->get_semaphore()->give();
         return;
     }
 
     /* check rdy bit */
-    if ((config & 0x80) != 0x80 ) {
+    if ((config[1] & 0x80) != 0x80 ) {
         _dev->get_semaphore()->give();
         return;
     }
 
-    if (!_dev->read_registers(ADS1115_RA_CONVERSION, (uint8_t *)&word,  sizeof(word))) {
+    if (!_dev->read_registers(ADS1115_RA_CONVERSION, (uint8_t *)&val,  sizeof(val))) {
         _dev->get_semaphore()->give();
         return;
     }
 
-    word = htobe16(word);
 
-    float sample = _convert_register_data_to_mv(word);
+    float sample = _convert_register_data_to_mv(be16toh(val));
 
     _samples[_channel_to_read].data = sample;
     _samples[_channel_to_read].id = _channel_to_read;