hal.c

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/*   Copyright (c) 2008, Swedish Institute of Computer Science
 *  All rights reserved. 
 *
 *  Additional fixes for AVR contributed by:
 *
 *	Colin O'Flynn [e-mail]
 *	Eric Gnoske [e-mail]
 *	Blake Leverett [e-mail]
 *	Mike Vidales [e-mail]
 *	Kevin Brown [e-mail]
 *	Nate Bohlmann [e-mail]
 *
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * 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.
 *   * Neither the name of the copyright holders nor the names of
 *     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 OWNER 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.
 *
 *  $Id: hal.c,v 1.2 2008/10/14 18:37:28 c_oflynn Exp $
*/

/**
 *   \addtogroup wireless
 *  @{
*/

/**
 *   \defgroup hal RF230 hardware level drivers
 *   @{
 */

/**
 *  \file
 *  This file contains low-level radio driver code.
 */



/*============================ INCLUDE =======================================*/
#include <stdlib.h>

#include "hal.h"
#include "at86rf230_registermap.h"
/*============================ MACROS ========================================*/

/*
 * Macros defined for the radio transceiver's access modes.
 *
 * These functions are implemented as macros since they are used very often.
 */
#define HAL_DUMMY_READ         (0x00) /**<  Dummy value for the SPI. */

#define HAL_TRX_CMD_RW         (0xC0) /**<  Register Write (short mode). */
#define HAL_TRX_CMD_RR         (0x80) /**<  Register Read (short mode). */
#define HAL_TRX_CMD_FW         (0x60) /**<  Frame Transmit Mode (long mode). */
#define HAL_TRX_CMD_FR         (0x20) /**<  Frame Receive Mode (long mode). */
#define HAL_TRX_CMD_SW         (0x40) /**<  SRAM Write. */
#define HAL_TRX_CMD_SR         (0x00) /**<  SRAM Read. */
#define HAL_TRX_CMD_RADDRM     (0x7F) /**<  Register Address Mask. */

#define HAL_CALCULATED_CRC_OK   (0) /**<  CRC calculated over the frame including the CRC field should be 0. */
/*============================ TYPDEFS =======================================*/
/*============================ VARIABLES =====================================*/
/** \brief This is a file internal variable that contains the 16 MSB of the
 *         system time.
 *
 *         The system time (32-bit) is the current time in microseconds. For the
 *         AVR microcontroller implementation this is solved by using a 16-bit
 *         timer (Timer1) with a clock frequency of 1MHz. The hal_system_time is
 *         incremented when the 16-bit timer overflows, representing the 16 MSB.
 *         The timer value it self (TCNT1) is then the 16 LSB.
 *
 *  \see hal_get_system_time
 */
static uint16_t hal_system_time = 0;

/*Flag section.*/
static uint8_t volatile hal_bat_low_flag; /**<  BAT_LOW flag. */
static uint8_t volatile hal_pll_lock_flag;   /**<  PLL_LOCK flag. */

/*Callbacks.*/

/** \brief This function is called when a rx_start interrupt is signaled.
 *
 *         If this function pointer is set to something else than NULL, it will
 *         be called when a RX_START event is signaled. The function takes two
 *         parameters: timestamp in IEEE 802.15.4 symbols (16 us resolution) and
 *         frame length. The event handler will be called in the interrupt domain,
 *         so the function must be kept short and not be blocking! Otherwise the
 *         system performance will be greatly degraded.
 *
 *  \see hal_set_rx_start_event_handler
 */
static hal_rx_start_isr_event_handler_t rx_start_callback;

/** \brief This function is called when a trx_end interrupt is signaled.
 *
 *         If this function pointer is set to something else than NULL, it will
 *         be called when a TRX_END event is signaled. The function takes one
 *         parameter: timestamp in IEEE 802.15.4 symbols (16 us resolution).
 *         The event handler will be called in the interrupt domain,
 *         so the function must not block!
 *
 *  \see hal_set_trx_end_event_handler
 */
static hal_trx_end_isr_event_handler_t trx_end_callback;
/*============================ PROTOTYPES ====================================*/
/*============================ IMPLEMENTATION ================================*/

/** \brief  This function initializes the Hardware Abstraction Layer.
 */
void
hal_init(void)
{
    /*Reset variables used in file.*/
    hal_system_time = 0;
    hal_reset_flags();

    /*IO Specific Initialization.*/
    DDR_SLP_TR |= (1 << SLP_TR); /* Enable SLP_TR as output. */
    DDR_RST    |= (1 << RST);    /* Enable RST as output. */

    /*SPI Specific Initialization.*/
    /* Set SS, CLK and MOSI as output. */
    HAL_DDR_SPI  |= (1 << HAL_DD_SS) | (1 << HAL_DD_SCK) | (1 << HAL_DD_MOSI);
    HAL_PORT_SPI |= (1 << HAL_DD_SS) | (1 << HAL_DD_SCK); /* Set SS and CLK high */
    /* Run SPI at max speed */
    SPCR         = (1 << SPE) | (1 << MSTR); /* Enable SPI module and master operation. */
    SPSR         = (1 << SPI2X); /* Enable doubled SPI speed in master mode. */

    /*TIMER1 Specific Initialization.*/
    TCCR1B = HAL_TCCR1B_CONFIG;       /* Set clock prescaler */
    TIFR1 |= (1 << ICF1);             /* Clear Input Capture Flag. */
    HAL_ENABLE_OVERFLOW_INTERRUPT(); /* Enable Timer1 overflow interrupt. */
    hal_enable_trx_interrupt();    /* Enable interrupts from the radio transceiver. */
}

/*----------------------------------------------------------------------------*/
/** \brief  This function reset the interrupt flags and interrupt event handlers
 *          (Callbacks) to their default value.
 */
void
hal_reset_flags(void)
{
    AVR_ENTER_CRITICAL_REGION();

    /* Reset Flags. */
    hal_bat_low_flag     = 0;
    hal_pll_lock_flag    = 0;

    /* Reset Associated Event Handlers. */
    rx_start_callback = NULL;
    trx_end_callback  = NULL;

    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  This function returns the current value of the BAT_LOW flag.
 *
 *  The BAT_LOW flag is incremented each time a BAT_LOW event is signaled from the
 *  radio transceiver. This way it is possible for the end user to poll the flag
 *  for new event occurances.
 */
uint8_t
hal_get_bat_low_flag(void)
{
    return hal_bat_low_flag;
}

/*----------------------------------------------------------------------------*/
/** \brief  This function clears the BAT_LOW flag.
 */
void
hal_clear_bat_low_flag(void)
{
    AVR_ENTER_CRITICAL_REGION();
    hal_bat_low_flag = 0;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  This function is used to set new TRX_END event handler, overriding
 *          old handler reference.
 */
hal_trx_end_isr_event_handler_t
hal_get_trx_end_event_handler(void)
{
    return trx_end_callback;
}

/*----------------------------------------------------------------------------*/
/** \brief  This function is used to set new TRX_END event handler, overriding
 *          old handler reference.
 */
void
hal_set_trx_end_event_handler(hal_trx_end_isr_event_handler_t trx_end_callback_handle)
{
    AVR_ENTER_CRITICAL_REGION();
    trx_end_callback = trx_end_callback_handle;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  Remove event handler reference.
 */
void
hal_clear_trx_end_event_handler(void)
{
    AVR_ENTER_CRITICAL_REGION();
    trx_end_callback = NULL;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  This function returns the active RX_START event handler
 *
 *  \return Current RX_START event handler registered.
 */
hal_rx_start_isr_event_handler_t
hal_get_rx_start_event_handler(void)
{
    return rx_start_callback;
}

/*----------------------------------------------------------------------------*/
/** \brief  This function is used to set new RX_START event handler, overriding
 *          old handler reference.
 */
void
hal_set_rx_start_event_handler(hal_rx_start_isr_event_handler_t rx_start_callback_handle)
{
    AVR_ENTER_CRITICAL_REGION();
    rx_start_callback = rx_start_callback_handle;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  Remove event handler reference.
 */
void
hal_clear_rx_start_event_handler(void)
{
    AVR_ENTER_CRITICAL_REGION();
    rx_start_callback = NULL;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  This function returns the current value of the PLL_LOCK flag.
 *
 *  The PLL_LOCK flag is incremented each time a PLL_LOCK event is signaled from the
 *  radio transceiver. This way it is possible for the end user to poll the flag
 *  for new event occurances.
 */
uint8_t
hal_get_pll_lock_flag(void)
{
    return hal_pll_lock_flag;
}

/*----------------------------------------------------------------------------*/
/** \brief  This function clears the PLL_LOCK flag.
 */
void
hal_clear_pll_lock_flag(void)
{
    AVR_ENTER_CRITICAL_REGION();
    hal_pll_lock_flag = 0;
    AVR_LEAVE_CRITICAL_REGION();
}

/*----------------------------------------------------------------------------*/
/** \brief  This function reads data from one of the radio transceiver's registers.
 *
 *  \param  address Register address to read from. See datasheet for register
 *                  map.
 *
 *  \see Look at the at86rf230_registermap.h file for register address definitions.
 *
 *  \returns The actual value of the read register.
 */
uint8_t
hal_register_read(uint8_t address)
{
    /* Add the register read command to the register address. */
    address &= HAL_TRX_CMD_RADDRM;
    address |= HAL_TRX_CMD_RR;

    uint8_t register_value = 0;

    AVR_ENTER_CRITICAL_REGION();

    HAL_SS_LOW(); /* Start the SPI transaction by pulling the Slave Select low. */

    /*Send Register address and read register content.*/
    SPDR = address;
    while ((SPSR & (1 << SPIF)) == 0) {;}
    register_value = SPDR;

    SPDR = register_value;
    while ((SPSR & (1 << SPIF)) == 0) {;}
    register_value = SPDR;

    HAL_SS_HIGH(); /* End the transaction by pulling the Slave Select High. */

    AVR_LEAVE_CRITICAL_REGION();

    return register_value;
}

/*----------------------------------------------------------------------------*/
/** \brief  This function writes a new value to one of the radio transceiver's
 *          registers.
 *
 *  \see Look at the at86rf230_registermap.h file for register address definitions.
 *
 *  \param  address Address of register to write.
 *  \param  value   Value to write.
 */
void
hal_register_write(uint8_t address, uint8_t value)
{
    /* Add the Register Write command to the address. */
    address = HAL_TRX_CMD_RW | (HAL_TRX_CMD_RADDRM & address);

    AVR_ENTER_CRITICAL_REGION();

    HAL_SS_LOW(); /* Start the SPI transaction by pulling the Slave Select low. */

    /*Send Register address and write register content.*/
    SPDR = address;
    while ((SPSR & (1 << SPIF)) == 0) {;}
    uint8_t dummy_read = SPDR;

    SPDR = value;
    while ((SPSR & (1 << SPIF)) == 0) {;}
    dummy_read = SPDR;

    HAL_SS_HIGH(); /* End the transaction by pulling the Slave Slect High. */

    AVR_LEAVE_CRITICAL_REGION();
}