ChibiOS/EX: added support for HTS221 humidity and temperature MEMS

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@9806 35acf78f-673a-0410-8e92-d51de3d6d3f4

3 files changed, 974 insertions, 0 deletions

diff --git a/os/ex/ST/hts221.c b/os/ex/ST/hts221.c
new file mode 100644
index 000000000..762478f9b
--- /dev/null
+++ b/os/ex/ST/hts221.c
@@ -0,0 +1,560 @@
+/*

+    ChibiOS - Copyright (C) 2016 Rocco Marco Guglielmi

+

+    This file is part of ChibiOS.

+

+    ChibiOS is free software; you can redistribute it and/or modify

+    it under the terms of the GNU General Public License as published by

+    the Free Software Foundation; either version 3 of the License, or

+    (at your option) any later version.

+

+    ChibiOS is distributed in the hope that it will be useful,

+    but WITHOUT ANY WARRANTY; without even the implied warranty of

+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+    GNU General Public License for more details.

+

+    You should have received a copy of the GNU General Public License

+    along with this program.  If not, see <http://www.gnu.org/licenses/>.

+	

+*/

+

+/**

+ * @file    hts221.c

+ * @brief   HTS221 MEMS interface module code.

+ *

+ * @addtogroup hts221

+ * @{

+ */

+

+#include "hal.h"

+#include "hts221.h"

+

+/*===========================================================================*/

+/* Driver local definitions.                                                 */

+/*===========================================================================*/

+

+#define HTS221_SEL(mask, offset)    (int16_t)(mask << offset)

+

+/*===========================================================================*/

+/* Driver exported variables.                                                */

+/*===========================================================================*/

+

+/*===========================================================================*/

+/* Driver local variables and types.                                         */

+/*===========================================================================*/

+

+static float hts221_bias[2] = {0.0f, 0.0f};

+static float hts221_sens[2] = {0.0f, 0.0f};

+

+/*===========================================================================*/

+/* Driver local functions.                                                   */

+/*===========================================================================*/

+

+#if (HTS221_USE_I2C) || defined(__DOXYGEN__)

+/**

+ * @brief   Reads registers value using I2C.

+ * @pre     The I2C interface must be initialized and the driver started.

+ *

+ * @param[in]  i2cp      pointer to the I2C interface

+ * @param[in]  reg       first sub-register address

+ * @param[out] rxbuf     pointer to an output buffer

+ * @return               the operation status.

+ * @param[in]  n         number of consecutive register to read

+ * @notapi

+ */

+msg_t hts221I2CReadRegister(I2CDriver *i2cp, uint8_t reg, uint8_t* rxbuf,

+                             size_t n) {

+  uint8_t txbuf = reg;

+  if(n > 1)

+    txbuf |= HTS221_SUB_MS;

+

+  return i2cMasterTransmitTimeout(i2cp, HTS221_SAD, &txbuf, 1, rxbuf, n,

+                                  TIME_INFINITE);

+}

+

+/**

+ * @brief   Writes a value into a register using I2C.

+ * @pre     The I2C interface must be initialized and the driver started.

+ *

+ * @param[in] i2cp       pointer to the I2C interface

+ * @param[in] txbuf      buffer containing sub-address value in first position

+ *                       and values to write

+ * @param[in] n          size of txbuf less one (not considering the first

+ *                       element)

+ * @return               the operation status.

+ * @notapi

+ */

+msg_t hts221I2CWriteRegister(I2CDriver *i2cp, uint8_t* txbuf, size_t n) {

+  if (n > 1)

+    (*txbuf) |= HTS221_SUB_MS;

+

+  return i2cMasterTransmitTimeout(i2cp, HTS221_SAD, txbuf, n + 1, NULL, 0,

+                                  TIME_INFINITE);

+}

+#endif /* HTS221_USE_I2C */

+

+/**

+ * @brief   Compute biases and sensitivities starting from data stored in

+ *          calibration registers.

+ * @notapi

+ *

+ * @param[in] dev        pointer to the HTS221 interface

+ * @return               the operation status.

+ */

+msg_t hts221Calibrate(HTS221Driver *devp) {

+  msg_t msg;

+  uint8_t calib[16], H0_rH_x2, H1_rH_x2, msb;

+  int16_t H0_T0_OUT, H1_T0_OUT, T0_degC_x8, T1_degC_x8, T0_OUT, T1_OUT;

+

+

+#if HTS221_SHARED_I2C

+  i2cAcquireBus(devp->config->i2cp);

+  i2cStart(devp->config->i2cp, devp->config->i2ccfg);

+#endif /* HTS221_SHARED_I2C */

+

+  /* Retrieving rH values from Calibration registers */

+	msg = hts221I2CReadRegister(devp->config->i2cp,

+                               HTS221_AD_CALIB_0, calib, 16);

+#if HTS221_SHARED_I2C

+    i2cReleaseBus(devp->config->i2cp);

+#endif /* HTS221_SHARED_I2C */

+															

+  H0_rH_x2 = calib[0];

+  H1_rH_x2 = calib[1];

+  H0_T0_OUT = calib[6];

+  H0_T0_OUT += calib[7] << 8;

+  H1_T0_OUT = calib[10];

+  H1_T0_OUT += calib[11] << 8;

+	

+  T0_degC_x8 = calib[2];

+  T1_degC_x8 = calib[3];

+

+  /* completing T0_degC_x8 value */

+  msb = (calib[5] & HTS221_SEL(0x03, 0));

+  if(msb & HTS221_SEL(0x01, 1)) {

+    msb |= HTS221_SEL(0x3F, 2);

+  }

+  T0_degC_x8 += msb << 8;

+

+  /* completing T1_degC_x8 value */

+  msb = ((calib[5] & HTS221_SEL(0x03, 2)) >> 2);

+  if(msb & HTS221_SEL(0x01, 1)) {

+    msb |= HTS221_SEL(0x3F, 2);

+  }

+  T1_degC_x8 += msb << 8;

+

+  T0_OUT = calib[12];

+  T0_OUT += calib[13] << 8;

+  T1_OUT = calib[14];

+  T1_OUT += calib[15] << 8;

+	

+

+  /* Storing data both in sensor data and in a reference variable used also

+     when user reset bias and sensitivity */

+  hts221_sens[0] = ((float)H1_rH_x2 - (float)H0_rH_x2) /

+                   (2.0f * ((float)H1_T0_OUT - (float)H0_T0_OUT));

+  devp->sensitivity[0] = hts221_sens[0];

+

+  hts221_bias[0] = (devp->sensitivity[0] * (float)H0_T0_OUT) -

+                   ((float)H0_rH_x2 / 2.0f);

+  devp->bias[0] = hts221_bias[0];

+

+  hts221_sens[1] = ((float)T1_degC_x8 - (float)T0_degC_x8) /

+                   (8.0f * ((float)T1_OUT - (float)T0_OUT));

+  devp->sensitivity[1] = hts221_sens[1];

+

+  hts221_bias[1] = (devp->sensitivity[1] * (float)T0_OUT) -

+                   ((float)T0_degC_x8 / 8.0f);

+  devp->bias[1] = hts221_bias[1];

+  return msg;

+}

+

+/*

+ * Interface implementation.

+ */

+static size_t hygro_get_axes_number(void *ip) {

+

+  osalDbgCheck(ip != NULL);

+  return HTS221_HYGRO_NUMBER_OF_AXES;

+}

+

+static size_t thermo_get_axes_number(void *ip) {

+

+  osalDbgCheck(ip != NULL);

+  return HTS221_THERMO_NUMBER_OF_AXES;

+}

+

+static size_t sens_get_axes_number(void *ip) {

+

+  osalDbgCheck(ip != NULL);

+  return (thermo_get_axes_number(ip) + hygro_get_axes_number(ip));

+}

+

+static msg_t hygro_read_raw(void *ip, int32_t axis[]) {

+  int16_t tmp;

+  uint8_t buff[2];

+  msg_t msg = MSG_OK;

+	

+  osalDbgCheck((ip != NULL) && (axis != NULL));

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY),

+              "hygro_read_raw(), invalid state");

+

+	*axis = 0.0f;

+#if HTS221_USE_I2C

+  osalDbgAssert((((HTS221Driver *)ip)->config->i2cp->state == I2C_READY),

+                "hygro_read_raw(), channel not ready");

+#if HTS221_SHARED_I2C

+  i2cAcquireBus(((HTS221Driver *)ip)->config->i2cp);

+  i2cStart(((HTS221Driver *)ip)->config->i2cp,

+           ((HTS221Driver *)ip)->config->i2ccfg);

+#endif /* HTS221_SHARED_I2C */

+

+

+  msg = hts221I2CReadRegister(((HTS221Driver *)ip)->config->i2cp,

+                              HTS221_AD_HUMIDITY_OUT_L, buff, 2);	

+#if HTS221_SHARED_I2C

+  i2cReleaseBus(((HTS221Driver *)ip)->config->i2cp);

+#endif /* HTS221_SHARED_I2C */

+#endif /* HTS221_USE_I2C */

+

+  if(msg == MSG_OK) {

+    tmp = buff[0] + (buff[1] << 8);

+    *axis = (int32_t)tmp;

+  }

+  return msg;

+}

+

+static msg_t thermo_read_raw(void *ip, int32_t axis[]) {

+  int16_t tmp;

+	uint8_t buff[2];

+  msg_t msg = MSG_OK;

+	

+  osalDbgCheck((ip != NULL) && (axis != NULL));

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY),

+              "thermo_read_raw(), invalid state");	

+	*axis = 0.0f;

+	

+#if HTS221_USE_I2C

+  osalDbgAssert((((HTS221Driver *)ip)->config->i2cp->state == I2C_READY),

+                "thermo_read_raw(), channel not ready");

+								

+#if HTS221_SHARED_I2C

+  i2cAcquireBus(((HTS221Driver *)ip)->config->i2cp);

+  i2cStart(((HTS221Driver *)ip)->config->i2cp,

+           ((HTS221Driver *)ip)->config->i2ccfg);

+#endif /* HTS221_SHARED_I2C */

+

+  msg = hts221I2CReadRegister(((HTS221Driver *)ip)->config->i2cp,

+                                  HTS221_AD_TEMP_OUT_L,

+                                  buff, 2);	

+																	

+#if HTS221_SHARED_I2C

+  i2cReleaseBus(((HTS221Driver *)ip)->config->i2cp);

+#endif /* HTS221_SHARED_I2C */

+#endif /* HTS221_USE_I2C */

+

+  if(msg == MSG_OK) {

+    tmp = buff[0] + (buff[1] << 8);

+    *axis = (int32_t)tmp;

+  }

+  return msg;

+}

+

+static msg_t sens_read_raw(void *ip, int32_t axes[]) {

+  int32_t* bp = axes;

+  msg_t msg;

+  msg = hygro_read_raw(ip, bp);

+  if (msg != MSG_OK){

+    return msg;

+  }

+  bp += HTS221_HYGRO_NUMBER_OF_AXES;

+  return thermo_read_raw(ip, bp);

+}

+

+static msg_t hygro_read_cooked(void *ip, float* axis) {

+  int32_t raw;

+  msg_t msg;

+

+  osalDbgCheck((ip != NULL) && (axis != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY),

+              "hygro_read_cooked(), invalid state");

+

+  msg = hygro_read_raw(ip, &raw);

+

+  *axis = raw * ((HTS221Driver *)ip)->sensitivity[0];

+  *axis -= ((HTS221Driver *)ip)->bias[0];

+  return msg;

+}

+

+static msg_t thermo_read_cooked(void *ip, float* axis) {

+  int32_t raw;

+  msg_t msg;

+

+  osalDbgCheck((ip != NULL) && (axis != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY),

+              "thermo_read_cooked(), invalid state");

+

+  msg = thermo_read_raw(ip, &raw);

+

+  *axis = raw * ((HTS221Driver *)ip)->sensitivity[1];

+  *axis -= ((HTS221Driver *)ip)->bias[1];

+  return msg;

+}

+

+static msg_t sens_read_cooked(void *ip, float axes[]) {

+  float *dp = axes;

+  msg_t msg;

+

+  osalDbgCheck((ip != NULL) && (axes != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY),

+              "sens_read_cooked(), invalid state");

+

+  msg = hygro_read_cooked(ip, dp);

+  if(msg != MSG_OK)

+    return msg;

+  dp += HTS221_THERMO_NUMBER_OF_AXES;

+  return thermo_read_cooked(ip, dp);

+}

+

+static msg_t hygro_set_bias(void *ip, float *bp) {

+  osalDbgCheck((ip != NULL) && (bp != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_set_bias(), invalid state");

+

+  ((HTS221Driver *)ip)->bias[0] = *bp;

+  return MSG_OK;

+}

+

+static msg_t thermo_set_bias(void *ip, float *bp) {

+  osalDbgCheck((ip != NULL) && (bp != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_set_bias(), invalid state");

+

+  ((HTS221Driver *)ip)->bias[1] = *bp;

+  return MSG_OK;

+}

+

+static msg_t hygro_reset_bias(void *ip) {

+  osalDbgCheck(ip != NULL);

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "hygro_reset_bias(), invalid state");

+

+  ((HTS221Driver *)ip)->bias[0] = 0;

+  return MSG_OK;

+}

+

+static msg_t thermo_reset_bias(void *ip) {

+  osalDbgCheck(ip != NULL);

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_reset_bias(), invalid state");

+

+  ((HTS221Driver *)ip)->bias[1] = 0;

+  return MSG_OK;

+}

+

+static msg_t hygro_set_sensitivity(void *ip, float *sp) {

+  osalDbgCheck((ip != NULL) && (sp != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_set_sensitivity(), invalid state");

+

+  ((HTS221Driver *)ip)->sensitivity[0] = *sp;

+  return MSG_OK;

+}

+

+static msg_t thermo_set_sensitivity(void *ip, float *sp) {

+  osalDbgCheck((ip != NULL) && (sp != NULL));

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_set_sensitivity(), invalid state");

+

+  ((HTS221Driver *)ip)->sensitivity[1] = *sp;

+  return MSG_OK;

+}

+

+static msg_t hygro_reset_sensitivity(void *ip) {

+  osalDbgCheck(ip != NULL);

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "hygro_reset_sensitivity(), invalid state");

+

+  ((HTS221Driver *)ip)->sensitivity[0] = HTS221_HYGRO_SENS;

+  return MSG_OK;

+}

+

+static msg_t thermo_reset_sensitivity(void *ip) {

+  osalDbgCheck(ip != NULL);

+

+  osalDbgAssert((((HTS221Driver *)ip)->state == HTS221_READY) ||

+                (((HTS221Driver *)ip)->state == HTS221_STOP),

+                "thermo_reset_sensitivity(), invalid state");

+

+  ((HTS221Driver *)ip)->sensitivity[1] = HTS221_THERMO_SENS;

+  return MSG_OK;

+}

+

+

+static const struct BaseSensorVMT vmt_basesensor = {

+  sens_get_axes_number, sens_read_raw, sens_read_cooked

+};

+

+static const struct BaseHygrometerVMT vmt_basehygrometer = {

+  hygro_get_axes_number, hygro_read_raw, hygro_read_cooked,

+  hygro_set_bias, hygro_reset_bias,

+  hygro_set_sensitivity, hygro_reset_sensitivity

+};

+

+static const struct BaseThermometerVMT vmt_basethermometer = {

+  thermo_get_axes_number, thermo_read_raw, thermo_read_cooked,

+  thermo_set_bias, thermo_reset_bias,

+  thermo_set_sensitivity, thermo_reset_sensitivity

+};

+

+/*===========================================================================*/

+/* Driver exported functions.                                                */

+/*===========================================================================*/

+

+/**

+ * @brief   Initializes an instance.

+ *

+ * @param[out] devp     pointer to the @p HTS221Driver object

+ *

+ * @init

+ */

+void hts221ObjectInit(HTS221Driver *devp) {

+

+  devp->vmt_basesensor = &vmt_basesensor;

+  devp->vmt_basehygrometer = &vmt_basehygrometer;

+  devp->vmt_basethermometer = &vmt_basethermometer;

+  devp->config = NULL;

+  devp->state  = HTS221_STOP;

+  devp->bias[0] = 0.0;

+  devp->bias[1] = 0.0;

+  devp->sensitivity[0] = 0.0;

+  devp->sensitivity[1] = 0.0;

+}

+

+/**

+ * @brief   Configures and activates HTS221 Complex Driver peripheral.

+ *

+ * @param[in] devp      pointer to the @p HTS221Driver object

+ * @param[in] config    pointer to the @p HTS221Config object

+ *

+ * @api

+ */

+void hts221Start(HTS221Driver *devp, const HTS221Config *config) {

+  uint8_t cr[2];

+  osalDbgCheck((devp != NULL) && (config != NULL));

+

+  osalDbgAssert((devp->state == HTS221_STOP) || (devp->state == HTS221_READY),

+              "hts221Start(), invalid state");			  

+

+  devp->config = config;

+

+#if HTS221_USE_I2C

+#if	HTS221_SHARED_I2C

+  i2cAcquireBus((devp)->config->i2cp);

+#endif /* HTS221_SHARED_I2C */

+  i2cStart((devp)->config->i2cp,

+           (devp)->config->i2ccfg);

+

+  /* Control register 1 configuration block.*/

+  {

+		cr[0] = HTS221_AD_CTRL_REG1;

+    cr[1] = devp->config->outputdatarate | HTS221_CTRL_REG1_PD;

+#if HTS221_USE_ADVANCED || defined(__DOXYGEN__)

+    cr[1] |= devp->config->blockdataupdate;

+

+#endif

+    hts221I2CWriteRegister(devp->config->i2cp, cr, 1);

+  }

+

+  /* Average register configuration block.*/

+  {

+		cr[0] = HTS221_AD_AV_CONF;

+    cr[1] = 0x05;

+#if HTS221_USE_ADVANCED || defined(__DOXYGEN__)

+    cr[1] = devp->config->reshumidity | devp->config->restemperature;

+

+#endif

+		hts221I2CWriteRegister(devp->config->i2cp, cr, 1);

+  }

+

+#if	HTS221_SHARED_I2C

+  i2cReleaseBus((devp)->config->i2cp);

+#endif /* HTS221_SHARED_I2C */  

+#endif /* HTS221_USE_I2C */

+

+  hts221Calibrate(devp);

+

+  if(devp->config->sensitivity != NULL) {

+    /* Taking Sensitivity from user configurations */

+    devp->sensitivity[0] = devp->config->sensitivity[0];

+    devp->sensitivity[1] = devp->config->sensitivity[1];

+  }

+

+  if(devp->config->bias != NULL) {

+    /* Taking Bias from user configurations */

+    devp->bias[0] = devp->config->bias[0];

+    devp->bias[1] = devp->config->bias[1];

+  }

+

+  /* This is the MEMS transient recovery time */

+  osalThreadSleepMilliseconds(5);

+

+  devp->state = HTS221_READY;

+} 

+

+/**

+ * @brief   Deactivates the HTS221 Complex Driver peripheral.

+ *

+ * @param[in] devp       pointer to the @p HTS221Driver object

+ *

+ * @api

+ */

+void hts221Stop(HTS221Driver *devp) {

+  uint8_t cr[2];

+

+  osalDbgCheck(devp != NULL);

+

+  osalDbgAssert((devp->state == HTS221_STOP) || (devp->state == HTS221_READY),

+                "hts221Stop(), invalid state");

+

+#if (HTS221_USE_I2C)

+  if (devp->state == HTS221_STOP) {

+#if	HTS221_SHARED_I2C

+    i2cAcquireBus((devp)->config->i2cp);

+    i2cStart((devp)->config->i2cp,

+             (devp)->config->i2ccfg);

+#endif /* HTS221_SHARED_I2C */

+

+  /* Control register 1 configuration block.*/

+  {

+    cr[0] = HTS221_AD_CTRL_REG1;

+    cr[1] = 0;

+    hts221I2CWriteRegister(devp->config->i2cp, cr, 1);

+  }

+	

+    i2cStop((devp)->config->i2cp);

+#if	HTS221_SHARED_I2C

+    i2cReleaseBus((devp)->config->i2cp);

+#endif /* HTS221_SHARED_I2C */    

+  }			  

+#endif /* HTS221_USE_I2C */

+  devp->state = HTS221_STOP;

+}

+/** @} */

diff --git a/os/ex/ST/hts221.h b/os/ex/ST/hts221.h
new file mode 100644
index 000000000..58c4af956
--- /dev/null
+++ b/os/ex/ST/hts221.h
@@ -0,0 +1,408 @@
+/*

+    ChibiOS - Copyright (C) 2016 Rocco Marco Guglielmi

+

+    This file is part of ChibiOS.

+

+    ChibiOS is free software; you can redistribute it and/or modify

+    it under the terms of the GNU General Public License as published by

+    the Free Software Foundation; either version 3 of the License, or

+    (at your option) any later version.

+

+    ChibiOS is distributed in the hope that it will be useful,

+    but WITHOUT ANY WARRANTY; without even the implied warranty of

+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+    GNU General Public License for more details.

+

+    You should have received a copy of the GNU General Public License

+    along with this program.  If not, see <http://www.gnu.org/licenses/>.

+	

+*/

+

+/**

+ * @file    hts221.h

+ * @brief   HTS221 MEMS interface module header.

+ *

+ * @{

+ */

+#ifndef _HTS221_H_

+#define _HTS221_H_

+

+#include "hal_hygrometer.h"

+#include "hal_thermometer.h"

+

+/*===========================================================================*/

+/* Driver constants.                                                         */

+/*===========================================================================*/

+

+/**

+ * @name    Version identification

+ * @{

+ */

+/**

+ * @brief   HTS221 driver version string.

+ */

+#define EX_HTS221_VERSION           "1.0.0"

+

+/**

+ * @brief   HTS221 driver version major number.

+ */

+#define EX_HTS221_MAJOR             1

+

+/**

+ * @brief   HTS221 driver version minor number.

+ */

+#define EX_HTS221_MINOR             0

+

+/**

+ * @brief   HTS221 driver version patch number.

+ */

+#define EX_HTS221_PATCH             0

+/** @} */

+

+/**

+ * @brief   HTS221 characteristics.
+ *

+ * @{

+ */
+#define HTS221_HYGRO_NUMBER_OF_AXES         1U
+#define HTS221_THERMO_NUMBER_OF_AXES        1U

+

+#define HTS221_HYGRO_SENS                   256.0f    /**< LSB/%rH          */

+#define HTS221_THERMO_SENS                  64.0f     /**< LSB/°C           */
+/** @} */
+
+/**
+ * @name    HTS221 communication interfaces related bit masks
+ * @{
+ */
+#define HTS221_DI_MASK              0xFF        /**< Data In mask           */
+#define HTS221_DI(n)                (1 << n)    /**< Data In bit n          */
+#define HTS221_AD_MASK              0x3F        /**< Address Data mask      */
+#define HTS221_AD(n)                (1 << n)    /**< Address Data bit n     */
+#define HTS221_MS                   (1 << 6)    /**< Multiple read write    */
+#define HTS221_RW                   (1 << 7)    /**< Read Write selector    */

+

+#define HTS221_SUB_MS               (1 << 7)    /**< Multiple RW in I2C mode*/

+

+#define HTS221_SAD                  0x5F        /**< Slave Address          */
+/** @} */
+
+/**
+ * @name    HTS221 register addresses
+ * @{
+ */

+#define HTS221_AD_WHO_AM_I          0x0F

+#define HTS221_AD_AV_CONF           0x10
+#define HTS221_AD_CTRL_REG1         0x20
+#define HTS221_AD_CTRL_REG2         0x21
+#define HTS221_AD_CTRL_REG3         0x22

+#define HTS221_AD_STATUS_REG        0x27
+#define HTS221_AD_HUMIDITY_OUT_L    0x28
+#define HTS221_AD_HUMIDITY_OUT_H    0x29
+#define HTS221_AD_TEMP_OUT_L        0x2A
+#define HTS221_AD_TEMP_OUT_H        0x2B

+#define HTS221_AD_CALIB_0           0x30

+#define HTS221_AD_CALIB_1           0x31

+#define HTS221_AD_CALIB_2           0x32

+#define HTS221_AD_CALIB_3           0x33

+#define HTS221_AD_CALIB_4           0x34

+#define HTS221_AD_CALIB_5           0x35

+#define HTS221_AD_CALIB_6           0x36

+#define HTS221_AD_CALIB_7           0x37

+#define HTS221_AD_CALIB_8           0x38

+#define HTS221_AD_CALIB_9           0x39

+#define HTS221_AD_CALIB_A           0x3A

+#define HTS221_AD_CALIB_B           0x3B

+#define HTS221_AD_CALIB_C           0x3C

+#define HTS221_AD_CALIB_D           0x3D

+#define HTS221_AD_CALIB_E           0x3E

+#define HTS221_AD_CALIB_F           0x3F
+/** @} */
+
+/**
+ * @name    HTS221_CTRL_REG1 register bits definitions
+ * @{
+ */
+#define HTS221_CTRL_REG1_MASK               0x87       
+#define HTS221_CTRL_REG1_ODR0               (1 << 0)
+#define HTS221_CTRL_REG1_ODR1               (1 << 1) 
+#define HTS221_CTRL_REG1_BDU                (1 << 2)
+#define HTS221_CTRL_REG1_PD                 (1 << 7)
+/** @} */
+
+/**

+ * @name    HTS221_CTRL_REG2 register bits definitions

+ * @{

+ */

+#define HTS221_CTRL_REG2_MASK               0x83       

+#define HTS221_CTRL_REG2_ONE_SHOT           (1 << 0)

+#define HTS221_CTRL_REG2_HEATER             (1 << 1) 

+#define HTS221_CTRL_REG2_BOOT               (1 << 7)

+/** @} */
+
+/**

+ * @name    HTS221_CTRL_REG3 register bits definitions

+ * @{

+ */

+#define HTS221_CTRL_REG3_MASK               0xC4       

+#define HTS221_CTRL_REG3_DRDY               (1 << 2) 

+#define HTS221_CTRL_REG3_PP_OD              (1 << 6)

+#define HTS221_CTRL_REG3_INT_H_L            (1 << 7)

+/** @} */

+

+/*===========================================================================*/
+/* Driver pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/**
+ * @name    Configuration options
+ * @{
+ */
+/**
+ * @brief   HTS221 SPI interface switch.
+ * @details If set to @p TRUE the support for SPI is included.
+ * @note    The default is @p FALSE.
+ */
+#if !defined(HTS221_USE_SPI) || defined(__DOXYGEN__)
+#define HTS221_USE_SPI                      FALSE
+#endif
+
+/**
+ * @brief   HTS221 I2C interface switch.
+ * @details If set to @p TRUE the support for I2C is included.
+ * @note    The default is @p TRUE.
+ */
+#if !defined(HTS221_USE_I2C) || defined(__DOXYGEN__)
+#define HTS221_USE_I2C                      TRUE
+#endif
+
+/**
+ * @brief   HTS221 advanced configurations switch.
+ * @details If set to @p TRUE more configurations are available.
+ * @note    The default is @p FALSE.
+ */
+#if !defined(HTS221_USE_ADVANCED) || defined(__DOXYGEN__)
+#define HTS221_USE_ADVANCED                 FALSE
+#endif
+
+/**
+ * @brief   HTS221 shared I2C switch.
+ * @details If set to @p TRUE the device acquires I2C bus ownership
+ *          on each transaction.
+ * @note    The default is @p FALSE. Requires I2C_USE_MUTUAL_EXCLUSION
+ */
+#if !defined(HTS221_SHARED_SPI) || defined(__DOXYGEN__)
+#define HTS221_SHARED_I2C                   FALSE
+#endif
+/** @} */
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+#if !(HTS221_USE_SPI ^ HTS221_USE_I2C)
+#error "HTS221_USE_SPI and HTS221_USE_I2C cannot be both true or both false"
+#endif
+
+#if HTS221_USE_SPI && !HAL_USE_SPI
+#error "HTS221_USE_SPI requires HAL_USE_SPI"
+#endif
+

+#if HTS221_USE_SPI

+#error "HTS221 over SPI still not supported"

+#endif

+
+#if HTS221_USE_I2C && !HAL_USE_I2C
+#error "HTS221_USE_I2C requires HAL_USE_I2C"
+#endif
+
+#if HTS221_SHARED_I2C && !I2C_USE_MUTUAL_EXCLUSION
+#error "HTS221_SHARED_I2C requires I2C_USE_MUTUAL_EXCLUSION"
+#endif

+

+/*

+ * TODO: Add SPI support.

+ */
+
+/*===========================================================================*/
+/* Driver data structures and types.                                         */
+/*===========================================================================*/
+
+/**
+ * @name    HTS221 data structures and types.
+ * @{
+ */

+/**
+ * @brief   HTS221 output data rate and bandwidth.
+ */
+typedef enum {

+  HTS221_ODR_ONE_SHOT = 0x00,       /**< One shot.                          */
+  HTS221_ODR_1HZ = 0x01,            /**< Output data rate 1 Hz.             */
+  HTS221_ODR_7HZ = 0x02,            /**< Output data rate 7 Hz.             */
+  HTS221_ODR_12P5HZ = 0x03,         /**< Output data rate 12.5 Hz.          */
+}hts221_odr_t;
+

+/**

+ * @brief   HTS221 humidity resolution.

+ */

+typedef enum {

+  HTS221_AVGH_4 = 0x00,             /**< Number of internal average is 4.   */

+  HTS221_AVGH_8 = 0x01,             /**< Number of internal average is 8.   */

+  HTS221_AVGH_16 = 0x02,            /**< Number of internal average is 16.  */

+  HTS221_AVGH_32 = 0x03,            /**< Number of internal average is 32.  */

+  HTS221_AVGH_64 = 0x04,            /**< Number of internal average is 64.  */

+  HTS221_AVGH_128 = 0x05,           /**< Number of internal average is 128. */

+  HTS221_AVGH_256 = 0x06,           /**< Number of internal average is 256. */

+  HTS221_AVGH_512 = 0x07            /**< Number of internal average is 512. */

+}hts221_avgh_t;

+

+/**

+ * @brief   HTS221 temperature resolution.

+ */

+typedef enum {

+  HTS221_AVGT_2 = 0x00,             /**< Number of internal average is 2.   */

+  HTS221_AVGT_4 = 0x08,             /**< Number of internal average is 4.   */

+  HTS221_AVGT_8 = 0x10,             /**< Number of internal average is 8.   */

+  HTS221_AVGT_16 = 0x18,            /**< Number of internal average is 16.  */

+  HTS221_AVGT_32 = 0x20,            /**< Number of internal average is 32.  */

+  HTS221_AVGT_64 = 0x28,            /**< Number of internal average is 64.  */

+  HTS221_AVGT_128 = 0x30,           /**< Number of internal average is 128. */

+  HTS221_AVGT_256 = 0x38,           /**< Number of internal average is 256. */

+}hts221_avgt_t;

+
+/**
+ * @brief   HTS221 block data update.
+ */
+typedef enum {
+  HTS221_BDU_CONTINUOUS = 0x00,     /**< Block data continuously updated.   */
+  HTS221_BDU_BLOCKED = 0x40         /**< Block data updated after reading.  */
+}hts221_bdu_t;
+
+/**
+ * @brief   Driver state machine possible states.
+ */
+typedef enum {
+  HTS221_UNINIT = 0,                /**< Not initialized.                   */
+  HTS221_STOP = 1,                  /**< Stopped.                           */
+  HTS221_READY = 2,                 /**< Ready.                             */
+} hts221_state_t;
+

+/**
+ * @brief   HTS221 configuration structure.
+ */
+typedef struct {
+
+#if HTS221_USE_SPI || defined(__DOXYGEN__)
+  /**
+   * @brief SPI driver associated to this HTS221.
+   */
+  SPIDriver                 *spip;
+  /**
+   * @brief SPI configuration associated to this HTS221.
+   */
+  const SPIConfig           *spicfg;
+#endif /* HTS221_USE_SPI */
+#if HTS221_USE_I2C || defined(__DOXYGEN__)
+  /**
+   * @brief I2C driver associated to this HTS221.
+   */
+  I2CDriver                 *i2cp;
+  /**
+   * @brief I2C configuration associated to this HTS221.
+   */
+  const I2CConfig           *i2ccfg;
+#endif /* HTS221_USE_I2C */
+  /**
+   * @brief HTS221 initial sensitivity.

+   * @note  Value are respectively related to hygrometer

+   *        and thermometer.
+   */
+  float*                    sensitivity;
+  /**
+   * @brief HTS221 initial bias.

+   * @note  Value are respectively related to hygrometer

+   *        and thermometer.
+   */
+  float*                    bias;
+  /**
+   * @brief HTS221 output data rate selection.
+   */
+  hts221_odr_t              outputdatarate;
+#if HTS221_USE_ADVANCED || defined(__DOXYGEN__)
+  /**
+   * @brief HTS221 block data update.
+   */
+  hts221_bdu_t              blockdataupdate;

+  /**

+   * @brief   HTS221 humidity resolution.

+   */

+  hts221_avgh_t             reshumidity;

+  /**

+   * @brief   HTS221 temperature resolution.

+   */

+  hts221_avgt_t             restemperature;
+#endif
+} HTS221Config;
+
+/**
+ * @brief   Structure representing a HTS221 driver.
+ */
+typedef struct HTS221Driver HTS221Driver;
+
+/**
+ * @brief   @p HTS221Driver specific data.
+ */
+#define _hts221_data                                                        \
+  _base_hygrometer_data                                                     \

+  _base_thermometer_data                                                    \
+  /* Driver state.*/                                                        \
+  hts221_state_t            state;                                          \
+  /* Current configuration data.*/                                          \
+  const HTS221Config        *config;                                        \
+  /* Current sensitivity data.*/                                            \
+  float                     sensitivity[HTS221_HYGRO_NUMBER_OF_AXES +       \

+                                        HTS221_THERMO_NUMBER_OF_AXES];      \
+  /* Current Bias data.*/                                                   \
+  float                     bias[HTS221_HYGRO_NUMBER_OF_AXES +              \

+                                 HTS221_THERMO_NUMBER_OF_AXES];
+
+/**
+ * @extends BaseGyroscope
+ *
+ * @brief   HTS221 3-axis barometer class.
+ * @details This class extends @p BaseGyroscope by adding physical
+ *          driver implementation.
+ */
+struct HTS221Driver {
+  /** @brief BaseSensor Virtual Methods Table. */
+  const struct BaseSensorVMT *vmt_basesensor;
+  /** @brief BaseHygrometer Virtual Methods Table. */
+  const struct BaseHygrometerVMT *vmt_basehygrometer;

+	  /** @brief BaseThermometer Virtual Methods Table. */

+  const struct BaseThermometerVMT *vmt_basethermometer;
+  _hts221_data
+};
+/** @} */
+
+/*===========================================================================*/
+/* Driver macros.                                                            */
+/*===========================================================================*/
+       
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void hts221ObjectInit(HTS221Driver *devp);
+  void hts221Start(HTS221Driver *devp, const HTS221Config *config);
+  void hts221Stop(HTS221Driver *devp);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _HTS221_H_ */
+
+/** @} */
+
diff --git a/os/ex/ST/hts221.mk b/os/ex/ST/hts221.mk
new file mode 100644
index 000000000..7e8c8d7e4
--- /dev/null
+++ b/os/ex/ST/hts221.mk
@@ -0,0 +1,6 @@
+# List of all the HTS221 device files.

+HTS221SRC := $(CHIBIOS)/os/ex/ST/hts221.c

+

+# Required include directories

+HTS221INC := $(CHIBIOS)/os/hal/lib/peripherals/sensors \

+             $(CHIBIOS)/os/ex/ST
\ No newline at end of file