Diff: targets/hal/TARGET_STM/TARGET_STM32L4/spi_api.c

Revision:

144:ef7eb2e8f9f7

Parent:

0:9b334a45a8ff

--- a/targets/hal/TARGET_STM/TARGET_STM32L4/spi_api.c	Tue Aug 02 14:07:36 2016 +0000
+++ b/targets/hal/TARGET_STM/TARGET_STM32L4/spi_api.c	Fri Sep 02 15:07:44 2016 +0100
@@ -1,336 +1,342 @@
-/* mbed Microcontroller Library
- *******************************************************************************
- * Copyright (c) 2015, STMicroelectronics
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- * 3. Neither the name of STMicroelectronics nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *******************************************************************************
- */
-#include "mbed_assert.h"
-#include "spi_api.h"
-
-#if DEVICE_SPI
-
-#include <math.h>
-#include "cmsis.h"
-#include "pinmap.h"
-#include "mbed_error.h"
-#include "PeripheralPins.h"
-
-static SPI_HandleTypeDef SpiHandle;
-
-static void init_spi(spi_t *obj)
-{
-    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
-
-    __HAL_SPI_DISABLE(&SpiHandle);
-
-    SpiHandle.Init.Mode              = obj->mode;
-    SpiHandle.Init.BaudRatePrescaler = obj->br_presc;
-    SpiHandle.Init.Direction         = SPI_DIRECTION_2LINES;
-    SpiHandle.Init.CLKPhase          = obj->cpha;
-    SpiHandle.Init.CLKPolarity       = obj->cpol;
-    SpiHandle.Init.CRCCalculation    = SPI_CRCCALCULATION_DISABLE;
-    SpiHandle.Init.CRCPolynomial     = 7;
-    SpiHandle.Init.CRCLength         = SPI_CRC_LENGTH_8BIT;
-    SpiHandle.Init.DataSize          = obj->bits;
-    SpiHandle.Init.FirstBit          = SPI_FIRSTBIT_MSB;
-    SpiHandle.Init.TIMode            = SPI_TIMODE_DISABLE;
-    SpiHandle.Init.NSS               = obj->nss;
-    SpiHandle.Init.NSSPMode          = SPI_NSS_PULSE_DISABLE;
-
-    if (HAL_SPI_Init(&SpiHandle) != HAL_OK) {
-        error("Cannot initialize SPI\n");
-    }
-
-    __HAL_SPI_ENABLE(&SpiHandle);
-}
-
-void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
-{
-    // Determine the SPI to use
-    SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
-    SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
-    SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
-    SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
-
-    SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
-    SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
-
-    obj->spi = (SPIName)pinmap_merge(spi_data, spi_cntl);
-    MBED_ASSERT(obj->spi != (SPIName)NC);
-
-    // Enable SPI clock
-    if (obj->spi == SPI_1) {
-        __HAL_RCC_SPI1_CLK_ENABLE();
-    }
-    if (obj->spi == SPI_2) {
-        __HAL_RCC_SPI2_CLK_ENABLE();
-    }
-    if (obj->spi == SPI_3) {
-        __HAL_RCC_SPI3_CLK_ENABLE();
-    }
-
-    // Configure the SPI pins
-    pinmap_pinout(mosi, PinMap_SPI_MOSI);
-    pinmap_pinout(miso, PinMap_SPI_MISO);
-    pinmap_pinout(sclk, PinMap_SPI_SCLK);
-
-    // Save new values
-    obj->bits = SPI_DATASIZE_8BIT;
-    obj->cpol = SPI_POLARITY_LOW;
-    obj->cpha = SPI_PHASE_1EDGE;
-    obj->br_presc = SPI_BAUDRATEPRESCALER_256;
-
-    obj->pin_miso = miso;
-    obj->pin_mosi = mosi;
-    obj->pin_sclk = sclk;
-    obj->pin_ssel = ssel;
-
-    if (ssel == NC) { // SW NSS Master mode
-        obj->mode = SPI_MODE_MASTER;
-        obj->nss = SPI_NSS_SOFT;
-    } else { // Slave
-        pinmap_pinout(ssel, PinMap_SPI_SSEL);
-        obj->mode = SPI_MODE_SLAVE;
-        obj->nss = SPI_NSS_HARD_INPUT;
-    }
-
-    init_spi(obj);
-}
-
-void spi_free(spi_t *obj)
-{
-    // Reset SPI and disable clock
-    if (obj->spi == SPI_1) {
-        __HAL_RCC_SPI1_FORCE_RESET();
-        __HAL_RCC_SPI1_RELEASE_RESET();
-        __HAL_RCC_SPI1_CLK_DISABLE();
-    }
-
-    if (obj->spi == SPI_2) {
-        __HAL_RCC_SPI2_FORCE_RESET();
-        __HAL_RCC_SPI2_RELEASE_RESET();
-        __HAL_RCC_SPI2_CLK_DISABLE();
-    }
-
-    if (obj->spi == SPI_3) {
-        __HAL_RCC_SPI3_FORCE_RESET();
-        __HAL_RCC_SPI3_RELEASE_RESET();
-        __HAL_RCC_SPI3_CLK_DISABLE();
-    }
-
-    // Configure GPIO
-    pin_function(obj->pin_miso, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
-    pin_function(obj->pin_mosi, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
-    pin_function(obj->pin_sclk, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
-    pin_function(obj->pin_ssel, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
-}
-
-void spi_format(spi_t *obj, int bits, int mode, int slave)
-{
-    // Save new values
-    if (bits == 16) {
-        obj->bits = SPI_DATASIZE_16BIT;
-    } else {
-        obj->bits = SPI_DATASIZE_8BIT;
-    }
-
-    switch (mode) {
-        case 0:
-            obj->cpol = SPI_POLARITY_LOW;
-            obj->cpha = SPI_PHASE_1EDGE;
-            break;
-        case 1:
-            obj->cpol = SPI_POLARITY_LOW;
-            obj->cpha = SPI_PHASE_2EDGE;
-            break;
-        case 2:
-            obj->cpol = SPI_POLARITY_HIGH;
-            obj->cpha = SPI_PHASE_1EDGE;
-            break;
-        default:
-            obj->cpol = SPI_POLARITY_HIGH;
-            obj->cpha = SPI_PHASE_2EDGE;
-            break;
-    }
-
-    if (slave == 0) {
-        obj->mode = SPI_MODE_MASTER;
-        obj->nss = SPI_NSS_SOFT;
-    } else {
-        obj->mode = SPI_MODE_SLAVE;
-        obj->nss = SPI_NSS_HARD_INPUT;
-    }
-
-    init_spi(obj);
-}
-
-void spi_frequency(spi_t *obj, int hz)
-{
-    // Values depend of PCLK1 and PCLK2: 80 MHz if MSI or HSI is used, 48 MHz if HSE is used
-    if (SystemCoreClock == 80000000) { // MSI or HSI
-        if (hz < 600000) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 313 kHz
-        } else if ((hz >= 600000) && (hz < 1000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 625 kHz
-        } else if ((hz >= 1000000) && (hz < 2000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 1.25 MHz (default)
-        } else if ((hz >= 2000000) && (hz < 5000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 2.5 MHz
-        } else if ((hz >= 5000000) && (hz < 10000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 5 MHz
-        } else if ((hz >= 10000000) && (hz < 20000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 10 MHz
-        } else if ((hz >= 20000000) && (hz < 40000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 20 MHz
-        } else { // >= 40000000
-            obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 40 MHz
-        }
-    } else { // 48 MHz - HSE
-        if (hz < 350000) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_256; // 188 kHz
-        } else if ((hz >= 350000) && (hz < 750000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_128; // 375 kHz
-        } else if ((hz >= 750000) && (hz < 1000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_64; // 750 kHz
-        } else if ((hz >= 1000000) && (hz < 3000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_32; // 1.5 MHz (default)
-        } else if ((hz >= 3000000) && (hz < 6000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_16; // 3 MHz
-        } else if ((hz >= 6000000) && (hz < 12000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_8; // 6 MHz
-        } else if ((hz >= 12000000) && (hz < 24000000)) {
-            obj->br_presc = SPI_BAUDRATEPRESCALER_4; // 12 MHz
-        } else { // >= 24000000
-            obj->br_presc = SPI_BAUDRATEPRESCALER_2; // 24 MHz
-        }
-    }
-
-    init_spi(obj);
-}
-
-static inline int ssp_readable(spi_t *obj)
-{
-    int status;
-    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
-    // Check if data is received
-    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_RXNE) != RESET) ? 1 : 0);
-    return status;
-}
-
-static inline int ssp_writeable(spi_t *obj)
-{
-    int status;
-    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
-    // Check if data is transmitted
-    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_TXE) != RESET) ? 1 : 0);
-    return status;
-}
-
-static inline void ssp_write(spi_t *obj, int value)
-{
-    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
-    while (!ssp_writeable(obj));
-    //spi->DR = (uint16_t)value;
-    if (obj->bits == SPI_DATASIZE_8BIT) {
-        // Force 8-bit access to the data register
-        uint8_t *p_spi_dr = 0;
-        p_spi_dr = (uint8_t *) & (spi->DR);
-        *p_spi_dr = (uint8_t)value;
-    } else { // SPI_DATASIZE_16BIT
-        spi->DR = (uint16_t)value;
-    }
-}
-
-static inline int ssp_read(spi_t *obj)
-{
-    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
-    while (!ssp_readable(obj));
-    //return (int)spi->DR;
-    if (obj->bits == SPI_DATASIZE_8BIT) {
-        // Force 8-bit access to the data register
-        uint8_t *p_spi_dr = 0;
-        p_spi_dr = (uint8_t *) & (spi->DR);
-        return (int)(*p_spi_dr);
-    } else {
-        return (int)spi->DR;
-    }
-}
-
-static inline int ssp_busy(spi_t *obj)
-{
-    int status;
-    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
-    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_BSY) != RESET) ? 1 : 0);
-    return status;
-}
-
-int spi_master_write(spi_t *obj, int value)
-{
-    ssp_write(obj, value);
-    return ssp_read(obj);
-}
-
-int spi_slave_receive(spi_t *obj)
-{
-    return (ssp_readable(obj) ? 1 : 0);
-};
-
-int spi_slave_read(spi_t *obj)
-{
-    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
-    while (!ssp_readable(obj));
-    //return (int)spi->DR;
-    if (obj->bits == SPI_DATASIZE_8BIT) {
-        // Force 8-bit access to the data register
-        uint8_t *p_spi_dr = 0;
-        p_spi_dr = (uint8_t *) & (spi->DR);
-        return (int)(*p_spi_dr);
-    } else {
-        return (int)spi->DR;
-    }
-}
-
-void spi_slave_write(spi_t *obj, int value)
-{
-    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
-    while (!ssp_writeable(obj));
-    //spi->DR = (uint16_t)value;
-    if (obj->bits == SPI_DATASIZE_8BIT) {
-        // Force 8-bit access to the data register
-        uint8_t *p_spi_dr = 0;
-        p_spi_dr = (uint8_t *) & (spi->DR);
-        *p_spi_dr = (uint8_t)value;
-    } else { // SPI_DATASIZE_16BIT
-        spi->DR = (uint16_t)value;
-    }
-}
-
-int spi_busy(spi_t *obj)
-{
-    return ssp_busy(obj);
-}
-
-#endif
+/* mbed Microcontroller Library
+ *******************************************************************************
+ * Copyright (c) 2015, STMicroelectronics
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of STMicroelectronics nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *******************************************************************************
+ */
+#include "mbed_assert.h"
+#include "spi_api.h"
+
+#if DEVICE_SPI
+
+#include <math.h>
+#include "cmsis.h"
+#include "pinmap.h"
+#include "mbed_error.h"
+#include "PeripheralPins.h"
+
+static SPI_HandleTypeDef SpiHandle;
+
+static void init_spi(spi_t *obj)
+{
+    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
+
+    __HAL_SPI_DISABLE(&SpiHandle);
+
+    SpiHandle.Init.Mode              = obj->mode;
+    SpiHandle.Init.BaudRatePrescaler = obj->br_presc;
+    SpiHandle.Init.Direction         = SPI_DIRECTION_2LINES;
+    SpiHandle.Init.CLKPhase          = obj->cpha;
+    SpiHandle.Init.CLKPolarity       = obj->cpol;
+    SpiHandle.Init.CRCCalculation    = SPI_CRCCALCULATION_DISABLE;
+    SpiHandle.Init.CRCPolynomial     = 7;
+    SpiHandle.Init.CRCLength         = SPI_CRC_LENGTH_8BIT;
+    SpiHandle.Init.DataSize          = obj->bits;
+    SpiHandle.Init.FirstBit          = SPI_FIRSTBIT_MSB;
+    SpiHandle.Init.TIMode            = SPI_TIMODE_DISABLE;
+    SpiHandle.Init.NSS               = obj->nss;
+    SpiHandle.Init.NSSPMode          = SPI_NSS_PULSE_DISABLE;
+
+    if (HAL_SPI_Init(&SpiHandle) != HAL_OK) {
+        error("Cannot initialize SPI\n");
+    }
+
+    __HAL_SPI_ENABLE(&SpiHandle);
+}
+
+void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
+{
+    // Determine the SPI to use
+    SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
+    SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
+    SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
+    SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
+
+    SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
+    SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
+
+    obj->spi = (SPIName)pinmap_merge(spi_data, spi_cntl);
+    MBED_ASSERT(obj->spi != (SPIName)NC);
+
+    // Enable SPI clock
+    if (obj->spi == SPI_1) {
+        __HAL_RCC_SPI1_CLK_ENABLE();
+    }
+#if defined(SPI2_BASE)
+    if (obj->spi == SPI_2) {
+        __HAL_RCC_SPI2_CLK_ENABLE();
+    }
+#endif
+    if (obj->spi == SPI_3) {
+        __HAL_RCC_SPI3_CLK_ENABLE();
+    }
+
+    // Configure the SPI pins
+    pinmap_pinout(mosi, PinMap_SPI_MOSI);
+    pinmap_pinout(miso, PinMap_SPI_MISO);
+    pinmap_pinout(sclk, PinMap_SPI_SCLK);
+
+    // Save new values
+    obj->bits = SPI_DATASIZE_8BIT;
+    obj->cpol = SPI_POLARITY_LOW;
+    obj->cpha = SPI_PHASE_1EDGE;
+    obj->br_presc = SPI_BAUDRATEPRESCALER_256;
+
+    obj->pin_miso = miso;
+    obj->pin_mosi = mosi;
+    obj->pin_sclk = sclk;
+    obj->pin_ssel = ssel;
+
+    if (ssel == NC) { // SW NSS Master mode
+        obj->mode = SPI_MODE_MASTER;
+        obj->nss = SPI_NSS_SOFT;
+    } else { // Slave
+        pinmap_pinout(ssel, PinMap_SPI_SSEL);
+        obj->mode = SPI_MODE_SLAVE;
+        obj->nss = SPI_NSS_HARD_INPUT;
+    }
+
+    init_spi(obj);
+}
+
+void spi_free(spi_t *obj)
+{
+    // Reset SPI and disable clock
+    if (obj->spi == SPI_1) {
+        __HAL_RCC_SPI1_FORCE_RESET();
+        __HAL_RCC_SPI1_RELEASE_RESET();
+        __HAL_RCC_SPI1_CLK_DISABLE();
+    }
+
+#if defined(SPI2_BASE)
+    if (obj->spi == SPI_2) {
+        __HAL_RCC_SPI2_FORCE_RESET();
+        __HAL_RCC_SPI2_RELEASE_RESET();
+        __HAL_RCC_SPI2_CLK_DISABLE();
+    }
+#endif
+
+    if (obj->spi == SPI_3) {
+        __HAL_RCC_SPI3_FORCE_RESET();
+        __HAL_RCC_SPI3_RELEASE_RESET();
+        __HAL_RCC_SPI3_CLK_DISABLE();
+    }
+
+    // Configure GPIO
+    pin_function(obj->pin_miso, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    pin_function(obj->pin_mosi, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    pin_function(obj->pin_sclk, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+    pin_function(obj->pin_ssel, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
+}
+
+void spi_format(spi_t *obj, int bits, int mode, int slave)
+{
+    // Save new values
+    if (bits == 16) {
+        obj->bits = SPI_DATASIZE_16BIT;
+    } else {
+        obj->bits = SPI_DATASIZE_8BIT;
+    }
+
+    switch (mode) {
+        case 0:
+            obj->cpol = SPI_POLARITY_LOW;
+            obj->cpha = SPI_PHASE_1EDGE;
+            break;
+        case 1:
+            obj->cpol = SPI_POLARITY_LOW;
+            obj->cpha = SPI_PHASE_2EDGE;
+            break;
+        case 2:
+            obj->cpol = SPI_POLARITY_HIGH;
+            obj->cpha = SPI_PHASE_1EDGE;
+            break;
+        default:
+            obj->cpol = SPI_POLARITY_HIGH;
+            obj->cpha = SPI_PHASE_2EDGE;
+            break;
+    }
+
+    if (slave == 0) {
+        obj->mode = SPI_MODE_MASTER;
+        obj->nss = SPI_NSS_SOFT;
+    } else {
+        obj->mode = SPI_MODE_SLAVE;
+        obj->nss = SPI_NSS_HARD_INPUT;
+    }
+
+    init_spi(obj);
+}
+
+static const uint16_t baudrate_prescaler_table[] =	{SPI_BAUDRATEPRESCALER_2,
+                                                    SPI_BAUDRATEPRESCALER_4,
+                                                    SPI_BAUDRATEPRESCALER_8,
+                                                    SPI_BAUDRATEPRESCALER_16,
+                                                    SPI_BAUDRATEPRESCALER_32,
+                                                    SPI_BAUDRATEPRESCALER_64,
+                                                    SPI_BAUDRATEPRESCALER_128,
+                                                    SPI_BAUDRATEPRESCALER_256};
+
+void spi_frequency(spi_t *obj, int hz)
+{
+	int spi_hz = 0;
+	uint8_t prescaler_rank = 0;
+
+	/* Get source clock depending on SPI instance */
+    switch ((int)obj->spi) {
+        case SPI_1:
+    			/* SPI_1. Source CLK is PCKL2 */
+    			spi_hz = HAL_RCC_GetPCLK2Freq();
+    			break;
+#if defined(SPI2_BASE)
+    		case SPI_2:
+#endif
+    		case SPI_3:
+    			/* SPI_2, SPI_3. Source CLK is PCKL1 */
+    			spi_hz = HAL_RCC_GetPCLK1Freq();
+    			break;
+    		default:
+    			error("SPI instance not set");
+    }
+
+	/* Define pre-scaler in order to get highest available frequency below requested frequency */
+	while ((spi_hz > hz) && (prescaler_rank < sizeof(baudrate_prescaler_table)/sizeof(baudrate_prescaler_table[0]))){
+		spi_hz = spi_hz / 2;
+		prescaler_rank++;
+	}
+
+	if (prescaler_rank <= sizeof(baudrate_prescaler_table)/sizeof(baudrate_prescaler_table[0])) {
+		obj->br_presc = baudrate_prescaler_table[prescaler_rank-1];
+	} else {
+		error("Couldn't setup requested SPI frequency");
+	}
+
+    init_spi(obj);
+}
+
+static inline int ssp_readable(spi_t *obj)
+{
+    int status;
+    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
+    // Check if data is received
+    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_RXNE) != RESET) ? 1 : 0);
+    return status;
+}
+
+static inline int ssp_writeable(spi_t *obj)
+{
+    int status;
+    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
+    // Check if data is transmitted
+    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_TXE) != RESET) ? 1 : 0);
+    return status;
+}
+
+static inline void ssp_write(spi_t *obj, int value)
+{
+    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
+    while (!ssp_writeable(obj));
+    //spi->DR = (uint16_t)value;
+    if (obj->bits == SPI_DATASIZE_8BIT) {
+        // Force 8-bit access to the data register
+        uint8_t *p_spi_dr = 0;
+        p_spi_dr = (uint8_t *) & (spi->DR);
+        *p_spi_dr = (uint8_t)value;
+    } else { // SPI_DATASIZE_16BIT
+        spi->DR = (uint16_t)value;
+    }
+}
+
+static inline int ssp_read(spi_t *obj)
+{
+    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
+    while (!ssp_readable(obj));
+    //return (int)spi->DR;
+    if (obj->bits == SPI_DATASIZE_8BIT) {
+        // Force 8-bit access to the data register
+        uint8_t *p_spi_dr = 0;
+        p_spi_dr = (uint8_t *) & (spi->DR);
+        return (int)(*p_spi_dr);
+    } else {
+        return (int)spi->DR;
+    }
+}
+
+static inline int ssp_busy(spi_t *obj)
+{
+    int status;
+    SpiHandle.Instance = (SPI_TypeDef *)(obj->spi);
+    status = ((__HAL_SPI_GET_FLAG(&SpiHandle, SPI_FLAG_BSY) != RESET) ? 1 : 0);
+    return status;
+}
+
+int spi_master_write(spi_t *obj, int value)
+{
+    ssp_write(obj, value);
+    return ssp_read(obj);
+}
+
+int spi_slave_receive(spi_t *obj)
+{
+    return (ssp_readable(obj) ? 1 : 0);
+};
+
+int spi_slave_read(spi_t *obj)
+{
+    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
+    while (!ssp_readable(obj));
+    //return (int)spi->DR;
+    if (obj->bits == SPI_DATASIZE_8BIT) {
+        // Force 8-bit access to the data register
+        uint8_t *p_spi_dr = 0;
+        p_spi_dr = (uint8_t *) & (spi->DR);
+        return (int)(*p_spi_dr);
+    } else {
+        return (int)spi->DR;
+    }
+}
+
+void spi_slave_write(spi_t *obj, int value)
+{
+    SPI_TypeDef *spi = (SPI_TypeDef *)(obj->spi);
+    while (!ssp_writeable(obj));
+    //spi->DR = (uint16_t)value;
+    if (obj->bits == SPI_DATASIZE_8BIT) {
+        // Force 8-bit access to the data register
+        uint8_t *p_spi_dr = 0;
+        p_spi_dr = (uint8_t *) & (spi->DR);
+        *p_spi_dr = (uint8_t)value;
+    } else { // SPI_DATASIZE_16BIT
+        spi->DR = (uint16_t)value;
+    }
+}
+
+int spi_busy(spi_t *obj)
+{
+    return ssp_busy(obj);
+}
+
+#endif