mspi.h

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/*
 * Copyright (c) 2012, TU Braunschweig.
 * 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 the Institute 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 INSTITUTE 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
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/**
 * \file
 *              MSPI driver definitions
 * \author
 *      Ulf Kulau <kulau@ibr.cs.tu-bs.de>
 */

/**
 * \addtogroup inga_bus_driver
 * @{
 */

/**
 * \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>
 * @{
 */

#ifndef MSPIDRV_H_
#define MSPIDRV_H_

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

#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

/********************************************************************
 * 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;

/**
 * \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);

/** @} */ // mspi_driver
/** @} */ // inga_bus_driver

#endif /* MSPIDRV_H_ */