mspi-drv.h

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/* Copyright (c) 2010, Ulf Kulau
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \addtogroup Drivers
 * @{
 *
 * \defgroup mspi_driver Master SPI Bus Driver (MSPI)
 *
 * <p>There are a lot of possibilities to realize a Serial Peripheral Interface (SPI) with the
 * ATmega1284p, but the hardware SPI is used by the transceiver chip AT86rf230. In combination
 * with contiki it is not possible to build up an SPI Bus with this hardware SPI.
 * A software SPI would be a solution, but the ATmega1284p provides another opportunity. The MSPI
 * (Maser SPI) is an alternative function of the USART. There are two independent hardware USART,
 *  so it is possible to use one for the default debug RS232 interface, while the other one is
 *  free to be used as an MSPI. The only difference between an normal SPI and the MSPI is, that
 *  MSPI only supports slaves on the bus.</p>
 * @{
 *
 */

/**
 * \file
 *              MSPI driver definitions
 * \author
 *      Ulf Kulau <kulau@ibr.cs.tu-bs.de>
 */


#ifndef MSPIDRV_H_
#define MSPIDRV_H_

#include <avr/io.h>
/*!
 * Enable or disable the MSPI-Bus Manager.
 *
 * \note The...
 */
#define MSPI_BUS_MANAGER        1
#if MSPI_BUS_MANAGER
#include "mspi-mgr.h"
#endif

#define MSPI_USART0                     0
#define MSPI_USART1                     1
/*\cond*/
#define MSPI_ENABLE                     (0xC0)
#define MSPI_DISABLE            (0x06)
#define MSPI_CS_DISABLE         0
#define MSPI_DUMMY_BYTE         0xFF
/*\endcond*/


#define MSPI_CS_PORT            PORTA
#define MSPI_CS_PORT_DDR        DDRA
#define MSPI_CS_PIN_0           PORTA5
#define MSPI_CS_PIN_1           PORTA6
#define MSPI_CS_PIN_2           PORTA7

/*!
 * This array holds the BCD for the 8 possible SPI devices, because the few amount
 * of port-pins made it necessary to use a BCD-Decimal-Encoder. The first item
 * (chip_select[0]) disables chip select. The other (chip_select[1] ...
 * chip_select[7]) holds the MSPI_SC_PORT information for the specific SPI device.
 *
 * \note This is a special solution for the raven based ibr sensor node. If you want
 * to use this driver for other applications, feel free to change the chip select
 * management
 */
static uint8_t cs_bcd[8] = {
                /*Chip Select Disable*/
                (0xFF & (0 << MSPI_CS_PIN_0) & (0 << MSPI_CS_PIN_1) & (0 << MSPI_CS_PIN_2)),
                /*Chip Select Enable for specific SPI device (1...7)*/
                (0x00 | (1 << MSPI_CS_PIN_0) | (0 << MSPI_CS_PIN_1) | (0 << MSPI_CS_PIN_2)), //1
                (0x00 | (0 << MSPI_CS_PIN_0) | (1 << MSPI_CS_PIN_1) | (0 << MSPI_CS_PIN_2)), //2
                (0x00 | (1 << MSPI_CS_PIN_0) | (1 << MSPI_CS_PIN_1) | (0 << MSPI_CS_PIN_2)), //3
                (0x00 | (0 << MSPI_CS_PIN_0) | (0 << MSPI_CS_PIN_1) | (1 << MSPI_CS_PIN_2)), //4
                (0x00 | (1 << MSPI_CS_PIN_0) | (0 << MSPI_CS_PIN_1) | (1 << MSPI_CS_PIN_2)), //5
                (0x00 | (0 << MSPI_CS_PIN_0) | (1 << MSPI_CS_PIN_1) | (1 << MSPI_CS_PIN_2)), //6
                (0x00 | (1 << MSPI_CS_PIN_0) | (1 << MSPI_CS_PIN_1) | (1 << MSPI_CS_PIN_2))  //7

};

/********************************************************************
 * MSPI mode:
 ********************************************************************/

/*!
 * MSPI Mode 0
 * \note <ul>
 *               <li> Leading Edge: Sample (Rising Edge)
 *               <li> Trailing Edge: Setup (Falling Edge)
 *               </ul>
 */
#define MSPI_MODE_0                     (0x00)
/*!
 * MSPI Mode 1
 * \note <ul>
 *               <li> Leading Edge: Setup (Rising Edge)
 *               <li> Trailing Edge: Sample (Falling Edge)
 *               </ul>
 */
#define MSPI_MODE_1                     (0x02)
/*!
 * MSPI Mode 2
 * \note <ul>
 *               <li> Leading Edge: Sample (Falling Edge)
 *               <li> Trailing Edge: Setup (Rising Edge)
 *               </ul>
 */
#define MSPI_MODE_2                     (0x01)
/*!
 * MSPI Mode 3
 * \note <ul>
 *               <li> Leading Edge: Setup (Falling Edge)
 *               <li> Trailing Edge: Sample (Rising Edge)
 *               </ul>
 */
#define MSPI_MODE_3                     (0x03)

/********************************************************************
 * MSPI BAUD Rate:
 ********************************************************************/

/*!
 * Maximum MSPI Baud Rate [bps]
 * \note The maximum baud rate is f_osc/2
 */
#define MSPI_BAUD_MAX           (0x00)
/*!
 * 2Mbps MSPI Baud Rate
 * \note Assumption: f_osc = 8 MHz
 */
#define MSPI_BAUD_2MBPS         (0x01)
/*!
 * 1Mbps MSPI Baud Rate
 * \note Assumption: f_osc = 8 MHz
 */
#define MSPI_BAUD_1MBPS         (0x03)


typedef struct {
 /*!
  * MSPI Baud Rate Register (USART0/USART1)
  */
  volatile uint16_t * UBRRn;
 /*!
  * MSPI Serial Clock Pin Data Direction Register (USART0/USART1)
  */
  volatile uint8_t * XCKn_DDR; //Uart0 = DDRB //Uart1 = DDRD
 /*!
  * MSPI Serial Clock Pin (USART0/USART1)
  */
  volatile uint8_t XCKn; //Uart0 = PORTB0 //Uart1 = PORTD4
 /*!
  * MSPIM Control and Status Register A (USART0/USART1)
  */
  volatile uint8_t * UCSRnA;
 /*!
  * MSPIM Control and Status Register B (USART0/USART1)
  */
  volatile uint8_t * UCSRnB;
 /*!
  * MSPIM Control and Status Register C (USART0/USART1)
  */
  volatile uint8_t * UCSRnC;
  /*!
   * MSPI I/O Data Register (USART0/USART1)
   */
  volatile uint8_t * UDRn;
} usart_t;

static usart_t usart_ports[2] = {
  {   // MSPI UART0
    &UBRR0,
    &DDRB,
     PORTB0,
    &UCSR0A,
    &UCSR0B,
    &UCSR0C,
    &UDR0
  },

  {  // MSPI UART1
        &UBRR1,
        &DDRD,
         PORTD4,
        &UCSR1A,
        &UCSR1B,
        &UCSR1C,
        &UDR1
  }
};

/**
 * \brief Initialize the selected USART in the MSPI mode
 *
 * \param mode Select the (M)SPI mode (MSPI_MODE_0 ...
 *            MSPI_MODE_3)
 * \param baud The MSPI BAUD rate. Sometimes it is necessary
 *        to reduce the SCK. Use MSPI_BAUD_MAX in common case.
 *
 */
void mspi_init(uint8_t cs, uint8_t mode, uint16_t baud);

/**
 * \brief This function can be use either to transmit or receive
 *        data via spi.
 *
 * \param data <ul>
 *                         <li>When use this function to transmit: Data byte, which
 *                         has to be transmit.
 *                         <li>When use this function to receive: Data value don't
 *                         care. (Dummy Byte, e.g. 0xFF)
 *                         </ul>
 * \return     <li>When use this function to transmit: The return value
 *                         doesn't care
 *             <li>When use this function to receive: Received data
 *             from the spi slave
 *             </ul>
 *
 * \note The various devices along the SPI Bus are separated by the
 *  Chip Select (cs). The assignment of the SPI-devices depends on
 *  the hardware wiring. The correct chip select an spi configuration
 *  will be done by the spi-bus.manager. Otherwise please ensure,
 *  which Chip Select and spi bus configuration belong to which
 *  SPI device.
 */
uint8_t mspi_transceive(uint8_t data);

/**
 * \brief This function enables the chip select by setting the
 *        needed I/O pins (BCD-Code)
 *
 * \param cs   Chip Select: Device ID
 */
void mspi_chip_select(uint8_t cs);

/**
 * \brief This function disables the chip select
 *
 * \param cs   Chip Select: Device ID
 */
void mspi_chip_release(uint8_t cs);

/**
 * \brief This function will set all MSPI registers to their
 *        default values.
 */
void mspi_deinit(void);

#endif /* MSPIDRV_H_ */