Revision 9:1f35e8bf427b, committed 2015-10-14

Comitter:

davide aliprandi <>

Date:

Wed Oct 14 16:50:22 2015 +0200

Parent:

8:527e203b709b

Child:

10:da29b5403ca1

Commit message:

"DevSPI" helper class added to handle SPI communication.

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/DevSPI/DevSPI.h	Wed Oct 14 16:50:22 2015 +0200
@@ -0,0 +1,199 @@
+/**
+ ******************************************************************************
+ * @file    DevSPI.h
+ * @author  AST / Software Platforms and Cloud
+ * @version V0.0.1
+ * @date    September 24th, 2015
+ * @brief   Header file for a special SPI class DevSPI which provides some
+ *          helper function for on-board communication.
+ ******************************************************************************
+ * @attention
+ *
+ * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
+ *
+ * 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.
+ *
+ ******************************************************************************
+ */
+
+/* Define to prevent from recursive inclusion --------------------------------*/
+#ifndef __DEV_SPI_H
+#define __DEV_SPI_H
+
+/* Includes ------------------------------------------------------------------*/
+#include "mbed.h"
+
+/* Classes -------------------------------------------------------------------*/
+/** Helper class DevSPI providing functions for multi-register SPI communication
+ *  common for a series of SPI devices.
+ */
+class DevSPI : public SPI
+{
+ public:
+    /*
+     * Create a DevSPI interface.
+     * @param mosi pin name of the MOSI pin of the SPI device to be used for communication.
+     * @param miso pin name of the MISO pin of the SPI device to be used for communication.
+     * @param sclk pin name of the SCLK pin of the SPI device to be used for communication.
+     */
+    DevSPI(PinName mosi, PinName miso, PinName sclk) : SPI(mosi, miso, sclk)
+    {
+        bits = 9;
+        mode = 0;
+        frequency_hz = 1E6;
+        setup_done = false;
+    }
+
+    /*
+     * Setup the spi.
+     * Typically:
+     *  + 8 bit data;
+     *  + high steady state clock;
+     *  + second edge capture;
+     *  + 1MHz clock rate.
+     *
+     * @param bits         Number of bits per SPI frame (4 - 16)
+     * @param mode         Clock polarity and phase mode (0 - 3)
+     * @param frequency_hz SCLK frequency in hz (default = 1MHz)
+     *
+     * @code
+     * mode | POL PHA
+     * -----+--------
+     *   0  |  0   0
+     *   1  |  0   1
+     *   2  |  1   0
+     *   3  |  1   1
+     * @endcode
+     */
+    void setup(int bits, int mode = 0, int frequency_hz = 1E6)
+    {
+        format(bits, mode);
+        frequency(frequency_hz);
+        setup_done = true;
+    }
+
+    /**
+     * @brief      Writes a buffer to the SPI peripheral device.
+     * @param[in]  pBuffer pointer to the buffer of data to send.
+     * @param[in]  ssel GPIO of the SSEL pin of the SPI device to be used for communication.
+     * @param[in]  NumBytesToWrite number of bytes to write.
+     * @retval     0 if ok.
+     * @note       When using the SPI in Interrupt-mode, remember to disable interrupts
+     *             before calling this function and to enable them again after.
+     */
+    int spi_write(uint8_t* pBuffer, DigitalOut ssel, uint16_t NumBytesToWrite)
+    {
+        /* Setup. */
+        if (!setup_done)
+        {
+            ssel = 1;
+            setup(8, 3, 1E6);
+            setup_done = true;
+        }
+
+        /* Select the chip. */
+        ssel = 0;
+        
+        /* Write data. */
+        for (int i = 0; i < NumBytesToWrite; i++)
+            write(pBuffer[i]);
+
+        /* Unselect the chip. */
+        ssel = 1;
+
+        return 0;
+    }
+
+    /**
+     * @brief      Reads a buffer from the SPI peripheral device.
+     * @param[out] pBuffer pointer to the buffer to read data into.
+     * @param[in]  ssel GPIO of the SSEL pin of the SPI device to be used for communication.
+     * @param[in]  NumBytesToRead number of bytes to read.
+     * @retval     0 if ok.
+     * @note       When using the SPI in Interrupt-mode, remember to disable interrupts
+     *             before calling this function and to enable them again after.
+     */
+    int spi_read(uint8_t* pBuffer, DigitalOut ssel, uint16_t NumBytesToRead)
+    {
+        /* Setup. */
+        if (!setup_done)
+        {
+            ssel = 1;
+            setup(8, 3, 1E6);
+            setup_done = true;
+        }
+
+        /* Select the chip. */
+        ssel = 0;
+        
+        /* Read data. */
+        for (int i = 0; i < NumBytesToRead; i++)
+            pBuffer[i] = write(0x00);
+
+        /* Unselect the chip. */
+        ssel = 1;
+
+        return 0;
+    }
+
+    /**
+     * @brief      Reads and write a buffer from/to the SPI peripheral device at the same time.
+     * @param[out] pBufferToRead pointer to the buffer to read data into.
+     * @param[in]  pBufferToWrite pointer to the buffer of data to send.
+     * @param[in]  ssel GPIO of the SSEL pin of the SPI device to be used for communication.
+     * @param[in]  NumBytes number of bytes to read and write.
+     * @retval     0 if ok.
+     * @note       When using the SPI in Interrupt-mode, remember to disable interrupts
+     *             before calling this function and to enable them again after.
+     */
+    int spi_read_write(uint8_t* pBufferToRead, uint8_t* pBufferToWrite, DigitalOut ssel, uint16_t NumBytes)
+    {
+        /* Setup. */
+        if (!setup_done)
+        {
+            ssel = 1;
+            setup(8, 3, 1E6);
+            setup_done = true;
+        }
+
+        /* Select the chip. */
+        ssel = 0;
+        
+        /* Read and write data at the same time. */
+        for (int i = 0; i < NumBytes; i++)
+            pBufferToRead[i] = write(pBufferToWrite[i]);
+
+        /* Unselect the chip. */
+        ssel = 1;
+
+        return 0;
+    }
+
+ protected:
+    bool setup_done;
+    int bits;
+    int mode;
+    int frequency_hz;
+};
+
+#endif /* __DEV_SPI_H */