tinySA/os/io/platforms/MSP430/serial_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file MSP430/serial_lld.c
 * @brief MSP430 low level serial driver code
 * @addtogroup MSP430_SERIAL
 * @{
 */

#include <ch.h>
#include <serial.h>

#include <signal.h>

#include "board.h"

#if USE_MSP430_USART0 || defined(__DOXYGEN__)
/** @brief USART0 serial driver identifier.*/
SerialDriver SD1;
#endif
#if USE_MSP430_USART1 || defined(__DOXYGEN__)
/** @brief USART1 serial driver identifier.*/
SerialDriver SD2;
#endif

/** @brief Driver default configuration.*/
static const SerialDriverConfig default_config = {
  UBR(DEFAULT_USART_BITRATE),
  0,
  CHAR
};

/*===========================================================================*/
/* Low Level Driver local functions.                                         */
/*===========================================================================*/

static void set_error(uint8_t urctl, SerialDriver *sdp) {
  sdflags_t sts = 0;

  if (urctl & OE)
    sts |= SD_OVERRUN_ERROR;
  if (urctl & PE)
    sts |= SD_PARITY_ERROR;
  if (urctl & FE)
    sts |= SD_FRAMING_ERROR;
  if (urctl & BRK)
    sts |= SD_BREAK_DETECTED;
  chSysLockFromIsr();
  sdAddFlagsI(sdp, sts);
  chSysUnlockFromIsr();
}

#if USE_MSP430_USART0 || defined(__DOXYGEN__)
static void notify1(void) {

  if (!(U0IE & UTXIE0)) {
    chSysLockFromIsr();
    U0TXBUF = (uint8_t)sdRequestDataI(&SD1);
    chSysUnlockFromIsr();
    U0IE |= UTXIE0;
  }
}

/**
 * @brief USART0 initialization.
 * @param[in] config the architecture-dependent serial driver configuration
 */
static void usart0_init(const SerialDriverConfig *config) {

  U0CTL = SWRST;                /* Resets the USART, it should already be.*/
  /* USART init */
  U0TCTL = SSEL0 | SSEL1;       /* SMCLK as clock source.*/
  U0MCTL = config->mod;         /* Modulator.*/
  U0BR1 = (uint8_t)(config->div >> 8);  /* Divider high.*/
  U0BR0 = (uint8_t)(config->div >> 0);  /* Divider low.*/
  /* Clear USART status.*/
  (void)U0RXBUF;
  U0RCTL = 0;
  /* USART enable.*/
  U0ME |= UTXE0 + URXE0;        /* Enables the USART.*/
  U0CTL = config->ctl & ~SWRST; /* Various settings, clears reset state.*/
  U0IE |= URXIE0;               /* Enables RX interrupt.*/
}

/**
 * @brief USART0 de-initialization.
 */
static void usart0_deinit(void) {

  U0IE &= ~URXIE0;
  U0CTL = SWRST;
}
#endif /* USE_MSP430_USART0 */

#if USE_MSP430_USART1 || defined(__DOXYGEN__)
static void notify2(void) {

  if (!(U1IE & UTXIE1)) {
    U1TXBUF = (uint8_t)sdRequestDataI(&SD2);
    U1IE |= UTXIE1;
  }
}

/**
 * @brief USART1 initialization.
 * @param[in] config the architecture-dependent serial driver configuration
 */
static void usart1_init(const SerialDriverConfig *config) {

  U1CTL = SWRST;                /* Resets the USART, it should already be.*/
  /* USART init.*/
  U1TCTL = SSEL0 | SSEL1;       /* SMCLK as clock source.*/
  U1MCTL = config->mod;         /* Modulator.*/
  U1BR1 = (uint8_t)(config->div >> 8);  /* Divider high.*/
  U1BR0 = (uint8_t)(config->div >> 0);  /* Divider low.*/
  /* Clear USART status.*/
  (void)U0RXBUF;
  U1RCTL = 0;
  /* USART enable.*/
  U1ME |= UTXE0 + URXE0;        /* Enables the USART.*/
  U1CTL = config->ctl & ~SWRST; /* Various settings, clears reset state.*/
  U1IE |= URXIE0;               /* Enables RX interrupt.*/
}

/**
 * @brief USART1 de-initialization.
 */
static void usart1_deinit(void) {

  U1IE &= ~URXIE0;
  U1CTL = SWRST;
}
#endif /* USE_MSP430_USART1 */

/*===========================================================================*/
/* Low Level Driver interrupt handlers.                                      */
/*===========================================================================*/

#if USE_MSP430_USART0 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(USART0TX_VECTOR) {
  msg_t b;

  CH_IRQ_PROLOGUE();

  chSysLockFromIsr();
  b = sdRequestDataI(&SD1);
  chSysUnlockFromIsr();
  if (b < Q_OK)
    U0IE &= ~UTXIE0;
  else
    U0TXBUF = b;

  CH_IRQ_EPILOGUE();
}

CH_IRQ_HANDLER(USART0RX_VECTOR) {
  uint8_t urctl;

  CH_IRQ_PROLOGUE();

  if ((urctl = U0RCTL) & RXERR)
    set_error(urctl, &SD1);
  chSysLockFromIsr();
  sdIncomingDataI(&SD1, U0RXBUF);
  chSysUnlockFromIsr();

  CH_IRQ_EPILOGUE();
}
#endif /* USE_MSP430_USART0 */

#if USE_MSP430_USART1 || defined(__DOXYGEN__)
CH_IRQ_HANDLER(USART1TX_VECTOR) {
  msg_t b;

  CH_IRQ_PROLOGUE();

  chSysLockFromIsr();
  b = sdRequestDataI(&SD2);
  chSysUnlockFromIsr();
  if (b < Q_OK)
    U1IE &= ~UTXIE1;
  else
    U1TXBUF = b;

  CH_IRQ_EPILOGUE();
}

CH_IRQ_HANDLER(USART1RX_VECTOR) {
  uint8_t urctl;

  CH_IRQ_PROLOGUE();

  if ((urctl = U1RCTL) & RXERR)
    set_error(urctl, &SD2);
  chSysLockFromIsr();
  sdIncomingDataI(&SD2, U1RXBUF);
  chSysUnlockFromIsr();

  CH_IRQ_EPILOGUE();
}
#endif /* USE_MSP430_USART1 */

/*===========================================================================*/
/* Low Level Driver exported functions.                                      */
/*===========================================================================*/

/**
 * Low level serial driver initialization.
 */
void sd_lld_init(void) {

#if USE_MSP430_USART0
  sdObjectInit(&SD1, NULL, notify1);
  /* I/O pins for USART0.*/
  P3SEL |= BV(4) + BV(5);
#endif

#if USE_MSP430_USART1
  sdObjectInit(&SD2, NULL, notify2);
  /* I/O pins for USART1.*/
  P3SEL |= BV(6) + BV(7);
#endif
}

/**
 * @brief Low level serial driver configuration and (re)start.
 *
 * @param[in] sdp pointer to a @p SerialDriver object
 * @param[in] config the architecture-dependent serial driver configuration.
 *                   If this parameter is set to @p NULL then a default
 *                   configuration is used.
 */
void sd_lld_start(SerialDriver *sdp, const SerialDriverConfig *config) {

  if (config == NULL)
    config = &default_config;

#if USE_MSP430_USART0
  if (&SD1 == sdp) {
    usart0_init(config);
    return;
  }
#endif
#if USE_MSP430_USART1
  if (&SD2 == sdp) {
    usart1_init(config);
    return;
  }
#endif
}

/**
 * @brief Low level serial driver stop.
 * @details De-initializes the USART, stops the associated clock, resets the
 *          interrupt vector.
 *
 * @param[in] sdp pointer to a @p SerialDriver object
 */
void sd_lld_stop(SerialDriver *sdp) {

#if USE_MSP430_USART0
  if (&SD1 == sdp) {
    usart0_deinit();
    return;
  }
#endif
#if USE_MSP430_USART1
  if (&SD2 == sdp) {
    usart1_deinit();
    return;
  }
#endif
}

/** @} */