nuttx/arch/z80/src/ez80/ez80_serial.c
2016-02-21 18:06:09 -06:00

844 lines
25 KiB
C

/****************************************************************************
* arch/z80/src/ez08/ez80_serial.c
*
* Copyright (C) 2008-2009, 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <semaphore.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/serial/serial.h>
#include <arch/serial.h>
#include <arch/io.h>
#include "chip/chip.h"
#include "up_internal.h"
#ifdef USE_SERIALDRIVER
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
struct ez80_dev_s
{
uint16_t uartbase; /* Base address of UART registers */
unsigned int baud; /* Configured baud */
uint8_t irq; /* IRQ associated with this UART */
uint8_t parity; /* 0=none, 1=odd, 2=even */
uint8_t bits; /* Number of bits (7 or 8) */
bool stopbits2; /* true: Configure with 2 (vs 1) */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int ez80_setup(struct uart_dev_s *dev);
static void ez80_shutdown(struct uart_dev_s *dev);
static int ez80_attach(struct uart_dev_s *dev);
static void ez80_detach(struct uart_dev_s *dev);
static int ez80_interrupt(int irq, void *context);
static int ez80_ioctl(struct file *filep, int cmd, unsigned long arg);
static int ez80_receive(struct uart_dev_s *dev, unsigned int *status);
static void ez80_rxint(struct uart_dev_s *dev, bool enable);
static bool ez80_rxavailable(struct uart_dev_s *dev);
static void ez80_send(struct uart_dev_s *dev, int ch);
static void ez80_txint(struct uart_dev_s *dev, bool enable);
static bool ez80_txready(struct uart_dev_s *dev);
static bool ez80_txempty(struct uart_dev_s *dev);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct uart_ops_s g_uart_ops =
{
ez80_setup, /* setup */
ez80_shutdown, /* shutdown */
ez80_attach, /* attach */
ez80_detach, /* detach */
ez80_ioctl, /* ioctl */
ez80_receive, /* receive */
ez80_rxint, /* rxint */
ez80_rxavailable, /* rxavailable */
#ifdef CONFIG_SERIAL_IFLOWCONTROL
NULL, /* rxflowcontrol */
#endif
ez80_send, /* send */
ez80_txint, /* txint */
ez80_txready, /* txready */
ez80_txempty /* txempty */
};
/* I/O buffers */
#ifdef CONFIG_EZ80_UART0
static char g_uart0rxbuffer[CONFIG_UART0_RXBUFSIZE];
static char g_uart0txbuffer[CONFIG_UART0_TXBUFSIZE];
#endif
#ifdef CONFIG_EZ80_UART1
static char g_uart1rxbuffer[CONFIG_UART1_RXBUFSIZE];
static char g_uart1txbuffer[CONFIG_UART1_TXBUFSIZE];
#endif
/* This describes the state of the UART0 port. */
#ifdef CONFIG_EZ80_UART0
static struct ez80_dev_s g_uart0priv =
{
EZ80_UART0_BASE, /* uartbase */
CONFIG_UART0_BAUD, /* baud */
EZ80_UART0_IRQ, /* irq */
CONFIG_UART0_PARITY, /* parity */
CONFIG_UART0_BITS, /* bits */
CONFIG_UART0_2STOP /* stopbits2 */
};
static uart_dev_t g_uart0port =
{
0, /* open_count */
false, /* xmitwaiting */
false, /* recvwaiting */
#ifdef CONFIG_UART0_SERIAL_CONSOLE
true, /* isconsole */
#else
false, /* isconsole */
#endif
{ 0 }, /* closesem */
{ 0 }, /* xmitsem */
{ 0 }, /* recvsem */
{
{ 0 }, /* xmit.sem */
0, /* xmit.head */
0, /* xmit.tail */
CONFIG_UART0_TXBUFSIZE, /* xmit.size */
g_uart0txbuffer, /* xmit.buffer */
},
{
{ 0 }, /* recv.sem */
0, /* recv.head */
0, /* recv.tail */
CONFIG_UART0_RXBUFSIZE, /* recv.size */
g_uart0rxbuffer, /* recv.buffer */
},
&g_uart_ops, /* ops */
&g_uart0priv, /* priv */
};
#endif
/* This describes the state of the UART1 port. */
#ifdef CONFIG_EZ80_UART1
static struct ez80_dev_s g_uart1priv =
{
EZ80_UART1_BASE, /* uartbase */
CONFIG_UART1_BAUD, /* baud */
EZ80_UART1_IRQ, /* irq */
CONFIG_UART1_PARITY, /* parity */
CONFIG_UART1_BITS, /* bits */
CONFIG_UART1_2STOP /* stopbits2 */
};
static uart_dev_t g_uart1port =
{
0, /* open_count */
false, /* xmitwaiting */
false, /* recvwaiting */
#ifdef CONFIG_UART1_SERIAL_CONSOLE
true, /* isconsole */
#else
false, /* isconsole */
#endif
{ 0 }, /* closesem */
{ 0 }, /* xmitsem */
{ 0 }, /* recvsem */
{
{ 0 }, /* xmit.sem */
0, /* xmit.head */
0, /* xmit.tail */
CONFIG_UART1_TXBUFSIZE, /* xmit.size */
g_uart1txbuffer, /* xmit.buffer */
},
{
{ 0 }, /* recv.sem */
0, /* recv.head */
0, /* recv.tail */
CONFIG_UART1_RXBUFSIZE, /* recv.size */
g_uart1rxbuffer, /* recv.buffer */
},
&g_uart_ops, /* ops */
&g_uart1priv, /* priv */
};
#endif
/* Now, which one with be tty0/console and which tty1? */
#if defined(CONFIG_UART0_SERIAL_CONSOLE) && defined(CONFIG_EZ80_UART0)
# define CONSOLE_DEV g_uart0port
# define TTYS0_DEV g_uart0port
# if defined(CONFIG_EZ80_UART1)
# define TTYS1_DEV g_uart1port
# endif
#elif defined(CONFIG_UART1_SERIAL_CONSOLE) && defined(CONFIG_EZ80_UART1)
# define CONSOLE_DEV g_uart1port
# define TTYS0_DEV g_uart1port
# if defined(CONFIG_EZ80_UART0)
# define TTYS1_DEV g_uart0port
# endif
#elif defined(CONFIG_EZ80_UART0)
# define TTYS0_DEV g_uart0port
# if defined(CONFIG_EZ80_UART1)
# define TTYS1_DEV g_uart1port
# endif
#elif defined(CONFIG_EZ80_UART0)
# define TTYS0_DEV g_uart1port
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ez80_serialin
****************************************************************************/
static inline uint8_t ez80_serialin(struct ez80_dev_s *priv, uint8_t offset)
{
return inp(priv->uartbase + offset);
}
/****************************************************************************
* Name: ez80_serialout
****************************************************************************/
static inline void ez80_serialout(struct ez80_dev_s *priv, uint8_t offset,
uint8_t value)
{
outp(priv->uartbase + offset, value);
}
/****************************************************************************
* Name: ez80_disableuartint
****************************************************************************/
static inline void ez80_disableuartint(struct ez80_dev_s *priv)
{
uint8_t ier = ez80_serialin(priv, EZ80_UART_IER);
ier &= ~EZ80_UARTEIR_INTMASK;
ez80_serialout(priv, EZ80_UART_IER, ier);
}
/****************************************************************************
* Name: ez80_restoreuartint
****************************************************************************/
static inline void ez80_restoreuartint(struct ez80_dev_s *priv, uint8_t bits)
{
uint8_t ier = ez80_serialin(priv, EZ80_UART_IER);
ier |= bits & (EZ80_UARTEIR_TIE|EZ80_UARTEIR_RIE);
ez80_serialout(priv, EZ80_UART_IER, ier);
}
/****************************************************************************
* Name: ez80_waittxready
****************************************************************************/
static inline void ez80_waittxready(struct ez80_dev_s *priv)
{
int tmp;
for (tmp = 1000 ; tmp > 0 ; tmp--)
{
if ((ez80_serialin(priv, EZ80_UART_LSR) & EZ80_UARTLSR_THRE) != 0)
{
break;
}
}
}
/****************************************************************************
* Name: ez80_setbaud
****************************************************************************/
static inline void ez80_setbaud(struct ez80_dev_s *priv, uint24_t baud)
{
uint32_t brg_divisor;
uint8_t lctl;
/* The resulting BAUD and depends on the system clock frequency and the
* BRG divisor as follows:
*
* BAUD = SYSTEM_CLOCK_FREQUENCY / (16 * BRG_Divisor)
*
* Or
*
* BRG_Divisor = SYSTEM_CLOCK_FREQUENCY / 16 / BAUD
*/
brg_divisor = (ez80_systemclock + (baud << 3)) / (baud << 4);
/* Set the DLAB bit to enable access to the BRG registers */
lctl = ez80_serialin(priv, EZ80_UART_LCTL);
lctl |= EZ80_UARTLCTL_DLAB;
ez80_serialout(priv, EZ80_UART_LCTL, lctl);
ez80_serialout(priv, EZ80_UART_BRGL, (uint8_t)(brg_divisor & 0xff));
ez80_serialout(priv, EZ80_UART_BRGH, (uint8_t)(brg_divisor >> 8));
lctl &= ~EZ80_UARTLCTL_DLAB;
ez80_serialout(priv, EZ80_UART_LCTL, lctl);
}
/****************************************************************************
* Name: ez80_setup
*
* Description:
* Configure the UART baud, bits, parity, fifos, etc. This method is called
* the first time that the serial port is opened.
*
****************************************************************************/
static int ez80_setup(struct uart_dev_s *dev)
{
#ifndef CONFIG_SUPPRESS_UART_CONFIG
struct ez80_dev_s *priv = dev->priv;
uint8_t reg;
uint8_t cval;
if (priv->bits == 7)
{
cval = EZ80_UARTCHAR_7BITS;
}
else
{
cval = EZ80_UARTCHAR_8BITS;
}
if (priv->stopbits2)
{
cval |= EZ80_UARTLCTL_2STOP;
}
if (priv->parity == 1) /* Odd parity */
{
cval |= (EZ80_UARTLCTL_PEN);
}
else if (priv->parity == 2) /* Even parity */
{
cval |= (EZ80_UARTLCTL_PEN|EZ80_UARTLCTL_EPS);
}
/* Set the baud rate */
ez80_disableuartint(priv);
ez80_setbaud(priv, priv->baud);
ez80_serialout(priv, EZ80_UART_MCTL, 0);
/* Set the character properties */
reg = (ez80_serialin(priv, EZ80_UART_LCTL) & ~EZ80_UARTLCTL_MASK) | cval;
ez80_serialout(priv, EZ80_UART_LCTL, reg);
/* Enable and flush the receive FIFO */
reg = EZ80_UARTFCTL_FIFOEN;
ez80_serialout(priv, EZ80_UART_FCTL, reg);
reg |= (EZ80_UARTFCTL_CLRTxF|EZ80_UARTFCTL_CLRRxF);
ez80_serialout(priv, EZ80_UART_FCTL, reg);
/* Set the receive trigger level to 4 */
reg |= EZ80_UARTTRIG_4;
ez80_serialout(priv, EZ80_UART_FCTL, reg);
#endif
return OK;
}
/****************************************************************************
* Name: ez80_shutdown
*
* Description:
* Disable the UART. This method is called when the serial port is closed
*
****************************************************************************/
static void ez80_shutdown(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
ez80_disableuartint(priv);
}
/****************************************************************************
* Name: ez80_attach
*
* Description:
* Configure the UART to operation in interrupt driven mode. This method is
* called when the serial port is opened. Normally, this is just after the
* the setup() method is called, however, the serial console may operate in
* a non-interrupt driven mode during the boot phase.
*
* RX and TX interrupts are not enabled when by the attach method (unless the
* hardware supports multiple levels of interrupt enabling). The RX and TX
* interrupts are not enabled until the txint() and rxint() methods are called.
*
****************************************************************************/
static int ez80_attach(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
/* Attach the IRQ */
return irq_attach(priv->irq, ez80_interrupt);
}
/****************************************************************************
* Name: ez80_detach
*
* Description:
* Detach UART interrupts. This method is called when the serial port is
* closed normally just before the shutdown method is called. The exception
* is the serial console which is never shutdown.
*
****************************************************************************/
static void ez80_detach(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
ez80_disableuartint(priv);
irq_detach(priv->irq);
}
/****************************************************************************
* Name: ez80_interrupt
*
* Description:
* This is the UART interrupt handler. It will be invoked
* when an interrupt received on the 'irq' It should call
* uart_transmitchars or uart_receivechar to perform the
* appropriate data transfers. The interrupt handling logic\
* must be able to map the 'irq' number into the approprite
* uart_dev_s structure in order to call these functions.
*
****************************************************************************/
static int ez80_interrupt(int irq, void *context)
{
struct uart_dev_s *dev = NULL;
struct ez80_dev_s *priv;
volatile uint32_t cause;
#ifdef CONFIG_EZ80_UART0
if (g_uart0priv.irq == irq)
{
dev = &g_uart0port;
}
else
#endif
#ifdef CONFIG_EZ80_UART1
if (g_uart1priv.irq == irq)
{
dev = &g_uart1port;
}
else
#endif
{
PANIC();
}
priv = (struct ez80_dev_s*)dev->priv;
cause = ez80_serialin(priv, EZ80_UART_IIR) & EZ80_UARTIIR_CAUSEMASK;
/* Check for character timeout (CTO) or Receiver Data Ready (RDR) */
if (cause == EZ80_UARTINSTS_CTO || cause == EZ80_UARTINSTS_RDR)
{
/* Receive characters from the RX fifo */
uart_recvchars(dev);
}
/* Check for transmission buffer empty */
else if (cause == EZ80_UARTINSTS_TBE)
{
uart_xmitchars(dev);
}
return OK;
}
/****************************************************************************
* Name: ez80_ioctl
*
* Description:
* All ioctl calls will be routed through this method
*
****************************************************************************/
static int ez80_ioctl(struct file *filep, int cmd, unsigned long arg)
{
return -ENOTTY;
}
/****************************************************************************
* Name: ez80_receive
*
* Description:
* Called (usually) from the interrupt level to receive one character from
* the UART. Error bits associated with the receipt are provided in the
* the return 'status'.
*
****************************************************************************/
static int ez80_receive(struct uart_dev_s *dev, unsigned int *status)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
uint8_t rbr = ez80_serialin(priv, EZ80_UART_RBR);
uint8_t lsr = ez80_serialin(priv, EZ80_UART_LSR);
*status = (unsigned int)lsr;
return rbr;
}
/****************************************************************************
* Name: ez80_rxint
*
* Description:
* Call to enable or disable RX interrupts
*
****************************************************************************/
static void ez80_rxint(struct uart_dev_s *dev, bool enable)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
uint8_t ier = ez80_serialin(priv, EZ80_UART_IER);
if (enable)
{
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
ier |= EZ80_UARTEIR_RIE;
ez80_serialout(priv, EZ80_UART_IER, ier);
#endif
}
else
{
ier &= ~EZ80_UARTEIR_RIE;
ez80_serialout(priv, EZ80_UART_IER, ier);
}
}
/****************************************************************************
* Name: ez80_rxavailable
*
* Description:
* Return true if the receive fifo is not empty
*
****************************************************************************/
static bool ez80_rxavailable(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
return (ez80_serialin(priv, EZ80_UART_LSR) & EZ80_UARTLSR_DR) != 0;
}
/****************************************************************************
* Name: ez80_send
*
* Description:
* This method will send one byte on the UART
*
****************************************************************************/
static void ez80_send(struct uart_dev_s *dev, int ch)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
ez80_serialout(priv, EZ80_UART_THR, (uint8_t)ch);
}
/****************************************************************************
* Name: ez80_txint
*
* Description:
* Call to enable or disable TX interrupts
*
****************************************************************************/
static void ez80_txint(struct uart_dev_s *dev, bool enable)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
uint8_t ier = ez80_serialin(priv, EZ80_UART_IER);
if (enable)
{
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
ier |= EZ80_UARTEIR_TIE;
ez80_serialout(priv, EZ80_UART_IER, ier);
#endif
}
else
{
ier &= ~EZ80_UARTEIR_TIE;
ez80_serialout(priv, EZ80_UART_IER, ier);
}
}
/****************************************************************************
* Name: ez80_txready
*
* Description:
* Return true if the tranmsit fifo is not full
*
****************************************************************************/
static bool ez80_txready(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
return (ez80_serialin(priv, EZ80_UART_LSR) & EZ80_UARTLSR_THRE) != 0;
}
/****************************************************************************
* Name: ez80_txempty
*
* Description:
* Return true if the transmit fifo is empty
*
****************************************************************************/
static bool ez80_txempty(struct uart_dev_s *dev)
{
struct ez80_dev_s *priv = (struct ez80_dev_s*)dev->priv;
return (ez80_serialin(priv, EZ80_UART_LSR) & EZ80_UARTLSR_TEMT) != 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_serialinit
*
* Description:
* Register serial console and serial ports.
*
****************************************************************************/
void up_serialinit(void)
{
uint8_t regval;
/* Make sure that all UART interrupts are disabled */
ez80_disableuartint(TTYS0_DEV.priv);
#ifdef TTYS1_DEV
ez80_disableuartint(TTYS1_DEV.priv);
#endif
/* Configure pins for usage of UARTs */
#ifdef CONFIG_EZ80_UART0
/* Set Port D, pins 0 and 1 for their alternate function (Mode 7) to enable UART0 */
regval = inp(EZ80_PD_DDR);
regval |= 3;
outp(EZ80_PD_DDR, regval);
regval = inp(EZ80_PD_ALT1);
regval &= ~3;
outp(EZ80_PD_ALT1, regval);
regval = inp(EZ80_PD_ALT2);
regval |= 3;
outp(EZ80_PD_ALT2, regval);
#endif
#ifdef CONFIG_EZ80_UART1
/* Set Port C, pins 0 and 1 for their alternate function (Mode 7) to enable UART1 */
regval = inp(EZ80_PC_DDR);
regval |= 3;
outp(EZ80_PC_DDR, regval);
regval = inp(EZ80_PC_ALT1);
regval &= ~3;
outp(EZ80_PC_ALT1, regval);
regval = inp(EZ80_PC_ALT2);
regval |= 3;
outp(EZ80_PC_ALT2, regval);
#endif
/* If there is a console, then configure the console now */
#ifdef CONSOLE_DEV
CONSOLE_DEV.isconsole = true;
ez80_setup(&CONSOLE_DEV);
#endif
/* Register console and tty devices */
#ifdef CONSOLE_DEV
(void)uart_register("/dev/console", &CONSOLE_DEV);
#endif
(void)uart_register("/dev/ttyS0", &TTYS0_DEV);
#ifdef TTYS1_DEV
(void)uart_register("/dev/ttyS1", &TTYS1_DEV);
#endif
}
/****************************************************************************
* Name: up_putc
*
* Description:
* Provide priority, low-level access to support OS debug
* writes
*
****************************************************************************/
int up_putc(int ch)
{
#ifdef CONSOLE_DEV
struct ez80_dev_s *priv = (struct ez80_dev_s*)CONSOLE_DEV.priv;
uint8_t ier = ez80_serialin(priv, EZ80_UART_IER);
ez80_disableuartint(priv);
/* Check for LF */
if (ch == '\n')
{
/* Output CR before LF*/
ez80_waittxready(priv);
ez80_serialout(priv, EZ80_UART_THR, '\r');
}
/* Output the character */
ez80_waittxready(priv);
ez80_serialout(priv, EZ80_UART_THR, (uint8_t)ch);
/* Wait for the character to be sent before re-enabling interrupts */
ez80_waittxready(priv);
ez80_restoreuartint(priv, ier);
return ch;
#endif
}
#else /* USE_SERIALDRIVER */
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_UART1_SERIAL_CONSOLE
# define ez80_inp(offs) inp((EZ80_UART1_BASE+(offs)))
# define ez80_outp(offs,val) outp((EZ80_UART1_BASE+(offs)), (val))
#else
# define ez80_inp(offs) inp((EZ80_UART0_BASE+(offs)))
# define ez80_outp(offs,val) outp((EZ80_UART0_BASE+(offs)), (val))
#endif
#define ez80_txready() ((ez80_inp(EZ80_UART_LSR) & EZ80_UARTLSR_THRE) != 0)
#define ez80_send(ch) ez80_outp(EZ80_UART_THR, ch)
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ez80_putc
****************************************************************************/
static void ez80_putc(int ch)
{
int tmp;
for (tmp = 1000 ; tmp > 0 && !ez80_txready(); tmp--);
ez80_send(ch);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_putc
****************************************************************************/
int up_putc(int ch)
{
/* Check for LF */
if (ch == '\n')
{
/* Output CR before LF */
ez80_putc('\r');
}
/* Output character */
ez80_putc(ch);
return ch;
}
#endif /* USE_SERIALDRIVER */