diff packages/devs/serial/h8300/h8300h/current/src/h8300_sci_serial.c @ 208:e0c0827131d1 ecos

Merge from eCos master repository on 2002-05-20-20:11:54-BST
author jlarmour
date Mon, 20 May 2002 22:19:26 +0000
parents
children d2c90368aeef
line wrap: on
line diff
new file mode 100644
--- /dev/null
+++ b/packages/devs/serial/h8300/h8300h/current/src/h8300_sci_serial.c
@@ -0,0 +1,576 @@
+//==========================================================================
+//
+//      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
+// Software Foundation; either version 2 or (at your option) any later version.
+//
+// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,
+// 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
+// License. However the source code for this file must still be made available
+// in accordance with section (3) of the GNU General Public License.
+//
+// This exception does not invalidate any other reasons why a work based on
+// this file might be covered by the GNU General Public License.
+//
+// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
+// at http://sources.redhat.com/ecos/ecos-license
+// -------------------------------------------
+//####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
+    0                                   // 8 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