Subversion Repositories openrisc_2011-10-31

//==========================================================================

//

//      h8300_sci_serial.c

//

//      H8/300 Serial SCI I/O Interface Module (interrupt driven)

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos 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

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// 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

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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

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//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   jskov

// Contributors:gthomas, jskov

// Date:        1999-05-24

// Purpose:     H8/300 Serial I/O module (interrupt driven version)

// Description: 

//

// Note: Since interrupt sources from the same SCI channel share the same

//       interrupt level, there is no risk of races when altering the

//       channel's control register from ISRs and DSRs. However, when 

//       altering the control register from user-level code, interrupts

//       must be disabled while the register is being accessed.

//

// FIXME: Receiving in polled mode prevents duplex transfers from working for

//        some reason.

//####DESCRIPTIONEND####

//==========================================================================

#include <pkgconf/io_serial.h>

#include <pkgconf/io.h>

// FIXME: This is necessary since the SCIF driver may be overriding

// CYGDAT_IO_SERIAL_DEVICE_HEADER. Need a better way to include two

// different drivers.

#include <pkgconf/io_serial_h8300_sci.h>

#include <cyg/io/io.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/io/devtab.h>

#include <cyg/infra/diag.h>

#include <cyg/io/serial.h>

#ifdef CYGDAT_IO_SERIAL_H8300_SCI

// The SCI controller register layout on the SH3/7708.

#define SCI_SCSMR                0      // serial mode register

#define SCI_SCBRR                1      // bit rate register

#define SCI_SCSCR                2      // serial control register

#define SCI_SCTDR                3      // transmit data register

#define SCI_SCSSR                4      // serial status register

#define SCI_SCRDR                5      // receive data register

#define SCI_SCSPTR               -4     // serial port register

static short select_word_length[] = {

    -1,

    -1,

    CYGARC_REG_SCSMR_CHR,               // 7 bits

};

static short select_stop_bits[] = {

    -1,

    0,                                  // 1 stop bit

    -1,

    CYGARC_REG_SCSMR_STOP               // 2 stop bits

};

static short select_parity[] = {

    0,                                  // No parity

    CYGARC_REG_SCSMR_PE,                // Even parity

    CYGARC_REG_SCSMR_PE|CYGARC_REG_SCSMR_OE, // Odd parity

    -1,

    -1

};

static unsigned short select_baud[] = {

    0,    // Unused

    CYGARC_SCBRR_CKSx(50)<<8 | CYGARC_SCBRR_N(50),

    CYGARC_SCBRR_CKSx(75)<<8 | CYGARC_SCBRR_N(75),

    CYGARC_SCBRR_CKSx(110)<<8 | CYGARC_SCBRR_N(110),

    CYGARC_SCBRR_CKSx(134)<<8 | CYGARC_SCBRR_N(134),

    CYGARC_SCBRR_CKSx(150)<<8 | CYGARC_SCBRR_N(150),

    CYGARC_SCBRR_CKSx(200)<<8 | CYGARC_SCBRR_N(200),

    CYGARC_SCBRR_CKSx(300)<<8 | CYGARC_SCBRR_N(300),

    CYGARC_SCBRR_CKSx(600)<<8 | CYGARC_SCBRR_N(600),

    CYGARC_SCBRR_CKSx(1200)<<8 | CYGARC_SCBRR_N(1200),

    CYGARC_SCBRR_CKSx(1800)<<8 | CYGARC_SCBRR_N(1800),

    CYGARC_SCBRR_CKSx(2400)<<8 | CYGARC_SCBRR_N(2400),

    CYGARC_SCBRR_CKSx(3600)<<8 | CYGARC_SCBRR_N(3600),

    CYGARC_SCBRR_CKSx(4800)<<8 | CYGARC_SCBRR_N(4800),

    CYGARC_SCBRR_CKSx(7200)<<8 | CYGARC_SCBRR_N(7200),

    CYGARC_SCBRR_CKSx(9600)<<8 | CYGARC_SCBRR_N(9600),

    CYGARC_SCBRR_CKSx(14400)<<8 | CYGARC_SCBRR_N(14400),

    CYGARC_SCBRR_CKSx(19200)<<8 | CYGARC_SCBRR_N(19200),

    CYGARC_SCBRR_CKSx(38400)<<8 | CYGARC_SCBRR_N(38400),

    CYGARC_SCBRR_CKSx(57600)<<8 | CYGARC_SCBRR_N(57600),

    CYGARC_SCBRR_CKSx(115200)<<8 | CYGARC_SCBRR_N(115200),

    CYGARC_SCBRR_CKSx(230400)<<8 | CYGARC_SCBRR_N(230400)

};

typedef struct h8300_sci_info {

    CYG_ADDRWORD   data;                // Pointer to data register

    CYG_WORD       er_int_num,          // Error interrupt number

                   rx_int_num,          // Receive interrupt number

                   tx_int_num;          // Transmit interrupt number

    CYG_ADDRWORD   ctrl_base;           // Base address of SCI controller

    cyg_interrupt  serial_er_interrupt,

                   serial_rx_interrupt,

                   serial_tx_interrupt;

    cyg_handle_t   serial_er_interrupt_handle,

                   serial_rx_interrupt_handle,

                   serial_tx_interrupt_handle;

    bool           tx_enabled;

} sh_sci_info;

static bool h8300_serial_init(struct cyg_devtab_entry *tab);

static bool h8300_serial_putc(serial_channel *chan, unsigned char c);

static Cyg_ErrNo h8300_serial_lookup(struct cyg_devtab_entry **tab,

                                   struct cyg_devtab_entry *sub_tab,

                                   const char *name);

static unsigned char h8300_serial_getc(serial_channel *chan);

static Cyg_ErrNo h8300_serial_set_config(serial_channel *chan, cyg_uint32 key,

                                      const void *xbuf, cyg_uint32 *len);

static void h8300_serial_start_xmit(serial_channel *chan);

static void h8300_serial_stop_xmit(serial_channel *chan);

static cyg_uint32 h8300_serial_tx_ISR(cyg_vector_t vector, cyg_addrword_t data);

static void       h8300_serial_tx_DSR(cyg_vector_t vector, cyg_ucount32 count,

                                   cyg_addrword_t data);

static cyg_uint32 h8300_serial_rx_ISR(cyg_vector_t vector, cyg_addrword_t data);

static void       h8300_serial_rx_DSR(cyg_vector_t vector, cyg_ucount32 count,

                                   cyg_addrword_t data);

static cyg_uint32 h8300_serial_er_ISR(cyg_vector_t vector, cyg_addrword_t data);

static void       h8300_serial_er_DSR(cyg_vector_t vector, cyg_ucount32 count,

                                   cyg_addrword_t data);

static SERIAL_FUNS(h8300_serial_funs,

                   h8300_serial_putc,

                   h8300_serial_getc,

                   h8300_serial_set_config,

                   h8300_serial_start_xmit,

                   h8300_serial_stop_xmit

    );

static h8300_sci_info h8300_serial_info =

{

    NULL,

    CYGNUM_HAL_INTERRUPT_ERI0,

    CYGNUM_HAL_INTERRUPT_RXI0,

    CYGNUM_HAL_INTERRUPT_TXI0,

    CYGARC_REG_SMR0

};

#if CYGNUM_IO_SERIAL_H8300_H8300H_SERIAL1_BUFSIZE > 0

static unsigned char h8300_serial_out_buf[CYGNUM_IO_SERIAL_H8300_CQ7708_SERIAL1_BUFSIZE];

static unsigned char h8300_serial_in_buf[CYGNUM_IO_SERIAL_H8300_CQ7708_SERIAL1_BUFSIZE];

static SERIAL_CHANNEL_USING_INTERRUPTS(h8300_serial_channel,

                                       h8300_serial_funs,

                                       h8300_serial_info,

                                       CYG_SERIAL_BAUD_RATE(CYGNUM_IO_SERIAL_H8300_H8300H_SERIAL1_BAUD),

                                       CYG_SERIAL_STOP_DEFAULT,

                                       CYG_SERIAL_PARITY_DEFAULT,

                                       CYG_SERIAL_WORD_LENGTH_DEFAULT,

                                       CYG_SERIAL_FLAGS_DEFAULT,

                                       &h8300_serial_out_buf[0],

                                       sizeof(h8300_serial_out_buf),

                                       &h8300_serial_in_buf[0],

                                       sizeof(h8300_serial_in_buf)

    );

#else

static SERIAL_CHANNEL(h8300_serial_channel,

                      h8300_serial_funs,

                      h8300_serial_info,

                      CYG_SERIAL_BAUD_RATE(CYGNUM_IO_SERIAL_H8300_H8300H_SERIAL1_BAUD),

                      CYG_SERIAL_STOP_DEFAULT,

                      CYG_SERIAL_PARITY_DEFAULT,

                      CYG_SERIAL_WORD_LENGTH_DEFAULT,

                      CYG_SERIAL_FLAGS_DEFAULT

    );

#endif

DEVTAB_ENTRY(h8300_serial_io,

             CYGDAT_IO_SERIAL_H8300_H8300H_SERIAL1_NAME,

             0,                 // Does not depend on a lower level interface

             &cyg_io_serial_devio,

             h8300_serial_init,

             h8300_serial_lookup,          // Serial driver may need initializing

             &h8300_serial_channel

    );

// Internal function to actually configure the hardware to desired baud rate,

// etc.

static bool

h8300_serial_config_port(serial_channel *chan, cyg_serial_info_t *new_config,

                      bool init)

{

    cyg_uint16 baud_divisor = select_baud[new_config->baud];

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _scr, _smr;

    // Check configuration request

    if ((-1 == select_word_length[(new_config->word_length -

                                  CYGNUM_SERIAL_WORD_LENGTH_5)])

        || -1 == select_stop_bits[new_config->stop]

        || -1 == select_parity[new_config->parity]

        || baud_divisor == 0)

        return false;

    // Disable SCI interrupts while changing hardware

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, 0);

    // Set databits, stopbits and parity.

    _smr = select_word_length[(new_config->word_length -

                               CYGNUM_SERIAL_WORD_LENGTH_5)] |

        select_stop_bits[new_config->stop] |

        select_parity[new_config->parity];

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSMR, _smr);

    // Set baud rate.

    _smr &= ~CYGARC_REG_SCSMR_CKSx_MASK;

    _smr |= baud_divisor >> 8;

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSMR, _smr);

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCBRR, baud_divisor & 0xff);

    // Clear the status register.

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, 0);

    if (init) {

        // Always enable transmitter and receiver.

        _scr = CYGARC_REG_SCSCR_TE | CYGARC_REG_SCSCR_RE;

        if (chan->out_cbuf.len != 0)

            _scr |= CYGARC_REG_SCSCR_TIE; // enable tx interrupts

        if (chan->in_cbuf.len != 0)

            _scr |= CYGARC_REG_SCSCR_RIE; // enable rx interrupts

    }

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    if (new_config != &chan->config) {

        chan->config = *new_config;

    }

    return true;

}

// Function to initialize the device.  Called at bootstrap time.

static bool

h8300_serial_init(struct cyg_devtab_entry *tab)

{

    serial_channel *chan = (serial_channel *)tab->priv;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

#ifdef CYGDBG_IO_INIT

    diag_printf("SH SERIAL init - dev: %x.%d\n",

                h8300_chan->data, h8300_chan->rx_int_num);

#endif

    // Really only required for interrupt driven devices

    (chan->callbacks->serial_init)(chan);

    if (chan->out_cbuf.len != 0) {

        cyg_drv_interrupt_create(h8300_chan->tx_int_num,

                                 3,

                                 (cyg_addrword_t)chan, // Data item passed to interrupt handler

                                 h8300_serial_tx_ISR,

                                 h8300_serial_tx_DSR,

                                 &h8300_chan->serial_tx_interrupt_handle,

                                 &h8300_chan->serial_tx_interrupt);

        cyg_drv_interrupt_attach(h8300_chan->serial_tx_interrupt_handle);

        cyg_drv_interrupt_unmask(h8300_chan->tx_int_num);

        h8300_chan->tx_enabled = false;

    }

    if (chan->in_cbuf.len != 0) {

        // Receive interrupt

        cyg_drv_interrupt_create(h8300_chan->rx_int_num,

                                 3,

                                 (cyg_addrword_t)chan, // Data item passed to interrupt handler

                                 h8300_serial_rx_ISR,

                                 h8300_serial_rx_DSR,

                                 &h8300_chan->serial_rx_interrupt_handle,

                                 &h8300_chan->serial_rx_interrupt);

        cyg_drv_interrupt_attach(h8300_chan->serial_rx_interrupt_handle);

        // Receive error interrupt

        cyg_drv_interrupt_create(h8300_chan->er_int_num,

                                 3,

                                 (cyg_addrword_t)chan, // Data item passed to interrupt handler

                                 h8300_serial_er_ISR,

                                 h8300_serial_er_DSR,

                                 &h8300_chan->serial_er_interrupt_handle,

                                 &h8300_chan->serial_er_interrupt);

        cyg_drv_interrupt_attach(h8300_chan->serial_er_interrupt_handle);

        // This unmasks both interrupt sources.

        cyg_drv_interrupt_unmask(h8300_chan->rx_int_num);

    }

    h8300_serial_config_port(chan, &chan->config, true);

    return true;

}

// This routine is called when the device is "looked" up (i.e. attached)

static Cyg_ErrNo

h8300_serial_lookup(struct cyg_devtab_entry **tab,

                  struct cyg_devtab_entry *sub_tab,

                  const char *name)

{

    serial_channel *chan = (serial_channel *)(*tab)->priv;

    // Really only required for interrupt driven devices

    (chan->callbacks->serial_init)(chan);

    return ENOERR;

}

// Send a character to the device output buffer.

// Return 'true' if character is sent to device

static bool

h8300_serial_putc(serial_channel *chan, unsigned char c)

{

    cyg_uint8 _ssr;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, _ssr);

    if (_ssr & CYGARC_REG_SCSSR_TDRE) {

// Transmit buffer is empty

        HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCTDR, c);

        // Clear empty flag.

        HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSSR,

                        CYGARC_REG_SCSSR_CLEARMASK & ~CYGARC_REG_SCSSR_TDRE);

        return true;

    } else {

// No space

        return false;

    }

}

// Fetch a character from the device input buffer, waiting if necessary

static unsigned char

h8300_serial_getc(serial_channel *chan)

{

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    unsigned char c;

    cyg_uint8 _ssr;

    do {

        HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, _ssr);

    } while ((_ssr & CYGARC_REG_SCSSR_RDRF) == 0);

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCRDR, c);

    // Clear buffer full flag.

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSSR,

                    CYGARC_REG_SCSSR_CLEARMASK & ~CYGARC_REG_SCSSR_RDRF);

    return c;

}

// Set up the device characteristics; baud rate, etc.

static Cyg_ErrNo

h8300_serial_set_config(serial_channel *chan, cyg_uint32 key,

                     const void *xbuf, cyg_uint32 *len)

{

    switch (key) {

    case CYG_IO_SET_CONFIG_SERIAL_INFO:

      {

        cyg_serial_info_t *config = (cyg_serial_info_t *)xbuf;

        if ( *len < sizeof(cyg_serial_info_t) ) {

            return -EINVAL;

        }

        *len = sizeof(cyg_serial_info_t);

        if ( true != h8300_serial_config_port(chan, config, false) )

            return -EINVAL;

      }

      break;

    default:

        return -EINVAL;

    }

    return ENOERR;

}

// Enable the transmitter on the device

static void

h8300_serial_start_xmit(serial_channel *chan)

{

    cyg_uint8 _scr;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    h8300_chan->tx_enabled = true;

    // Mask the interrupts (all sources of the unit) while changing

    // the CR since a rx interrupt in the middle of this would result

    // in a bad CR state.

    cyg_drv_interrupt_mask(h8300_chan->rx_int_num);

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr |= CYGARC_REG_SCSCR_TIE;       // Enable xmit interrupt

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    cyg_drv_interrupt_unmask(h8300_chan->rx_int_num);

}

// Disable the transmitter on the device

static void

h8300_serial_stop_xmit(serial_channel *chan)

{

    cyg_uint8 _scr;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    h8300_chan->tx_enabled = false;

    // Mask the interrupts (all sources of the unit) while changing

    // the CR since a rx interrupt in the middle of this would result

    // in a bad CR state.

    cyg_drv_interrupt_mask(h8300_chan->rx_int_num);

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr &= ~CYGARC_REG_SCSCR_TIE;      // Disable xmit interrupt

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    cyg_drv_interrupt_unmask(h8300_chan->rx_int_num);

}

// Serial I/O - low level tx interrupt handler (ISR)

static cyg_uint32

h8300_serial_tx_ISR(cyg_vector_t vector, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _scr;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr &= ~CYGARC_REG_SCSCR_TIE;      // mask out tx interrupts

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    return CYG_ISR_CALL_DSR;  // Cause DSR to be run

}

// Serial I/O - high level tx interrupt handler (DSR)

static void

h8300_serial_tx_DSR(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    (chan->callbacks->xmt_char)(chan);

    if (h8300_chan->tx_enabled) {

        cyg_uint8 _scr;

        HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

        _scr |= CYGARC_REG_SCSCR_TIE;       // unmask tx interrupts

        HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    }

}

// Serial I/O - low level RX interrupt handler (ISR)

static cyg_uint32

h8300_serial_rx_ISR(cyg_vector_t vector, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _scr;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr &= ~CYGARC_REG_SCSCR_RIE;      // mask rx interrupts

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    return CYG_ISR_CALL_DSR;  // Cause DSR to be run

}

// Serial I/O - high level rx interrupt handler (DSR)

static void

h8300_serial_rx_DSR(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _ssr, _scr;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, _ssr);

    if (_ssr & CYGARC_REG_SCSSR_RDRF) {

        cyg_uint8 _c;

        HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCRDR, _c);

        // Clear buffer full flag.

        HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSSR,

                        CYGARC_REG_SCSSR_CLEARMASK & ~CYGARC_REG_SCSSR_RDRF);

        (chan->callbacks->rcv_char)(chan, _c);

    }

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr |= CYGARC_REG_SCSCR_RIE;       // unmask rx interrupts

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

}

static volatile int h8300_serial_error_orer = 0;

static volatile int h8300_serial_error_fer = 0;

static volatile int h8300_serial_error_per = 0;

// Serial I/O - low level error interrupt handler (ISR)

static cyg_uint32

h8300_serial_er_ISR(cyg_vector_t vector, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _scr;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr &= ~CYGARC_REG_SCSCR_RIE;      // mask rx interrupts

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    return CYG_ISR_CALL_DSR;            // Cause DSR to be run

}

// Serial I/O - high level error interrupt handler (DSR)

static void

h8300_serial_er_DSR(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)

{

    serial_channel *chan = (serial_channel *)data;

    h8300_sci_info *h8300_chan = (h8300_sci_info *)chan->dev_priv;

    cyg_uint8 _ssr, _ssr2, _scr;

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, _ssr);

    _ssr2 = CYGARC_REG_SCSSR_CLEARMASK;

    if (_ssr & CYGARC_REG_SCSSR_ORER) {

        _ssr2 &= ~CYGARC_REG_SCSSR_ORER;

        h8300_serial_error_orer++;

    }

    if (_ssr & CYGARC_REG_SCSSR_FER) {

        _ssr2 &= ~CYGARC_REG_SCSSR_FER;

        h8300_serial_error_fer++;

    }

    if (_ssr & CYGARC_REG_SCSSR_PER) {

        _ssr2 &= ~CYGARC_REG_SCSSR_PER;

        h8300_serial_error_per++;

    }

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSSR, _ssr2);

    HAL_READ_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

    _scr |= CYGARC_REG_SCSCR_RIE;       // unmask rx interrupts

    HAL_WRITE_UINT8(h8300_chan->ctrl_base+SCI_SCSCR, _scr);

}

#endif // ifdef CYGDAT_IO_SERIAL_H8300_SCI