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/**************************************************************************
* arch/sh/src/sh1/sh1_lowputc.c
*
* Copyright (C) 2008-2009 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 <stdint.h>
#include <nuttx/arch.h>
#include "up_internal.h"
#include "up_arch.h"
#include "chip.h"
#include "up_internal.h"
/**************************************************************************
* Private Definitions
**************************************************************************/
/* Configuration **********************************************************/
/* Is there a serial console? */
#if defined(CONFIG_SCI0_SERIAL_CONSOLE) && defined(CONFIG_SH1_SCI0)
# define HAVE_CONSOLE 1
# undef CONFIG_SCI1_SERIAL_CONSOLE
#elif defined(CONFIG_SCI1_SERIAL_CONSOLE) && defined(CONFIG_SH1_SCI1)
# define HAVE_CONSOLE 1
# undef CONFIG_SCI0_SERIAL_CONSOLE
#else
# if defined(CONFIG_SCI0_SERIAL_CONSOLE) || defined(CONFIG_SCI1_SERIAL_CONSOLE)
# error "Serial console selected, but corresponding SCI not enabled"
# endif
# undef HAVE_CONSOLE
#endif
/* Select UART parameters for the selected console */
#if defined(CONFIG_SCI0_SERIAL_CONSOLE)
# define SH1_SCI_BASE SH1_SCI0_BASE
# define SH1_SCI_BAUD CONFIG_SCI0_BAUD
# define SH1_SCI_BITS CONFIG_SCI0_BITS
# define SH1_SCI_PARITY CONFIG_SCI0_PARITY
# define SH1_SCI_2STOP CONFIG_SCI0_2STOP
#elif defined(CONFIG_SCI1_SERIAL_CONSOLE)
# define SH1_SCI_BASE SH1_SCI1_BASE
# define SH1_SCI_BAUD CONFIG_SCI1_BAUD
# define SH1_SCI_BITS CONFIG_SCI1_BITS
# define SH1_SCI_PARITY CONFIG_SCI1_PARITY
# define SH1_SCI_2STOP CONFIG_SCI1_2STOP
#else
# error "No CONFIG_SCIn_SERIAL_CONSOLE Setting"
#endif
/* Get mode setting */
#if SH1_SCI_BITS == 7
# define SH1_SMR_MODE SH1_SCISMR_CHR
#elif SH1_SCI_BITS == 8
# define SH1_SMR_MODE (0)
#else
# error "Number of bits not supported"
#endif
#if SH1_SCI_PARITY == 0
# define SH1_SMR_PARITY (0)
#elif SH1_SCI_PARITY == 1
# define SH1_SMR_PARITY (SH1_SCISMR_PE|SH1_SCISMR_OE)
#elif SH1_SCI_PARITY == 2
# define SH1_SMR_PARITY SH1_SCISMR_PE
#else
# error "Invalid parity selection"
#endif
#if SH1_SCI_2STOP != 0
# define SH1_SMR_STOP SH1_SCISMR_STOP
#else
# define SH1_SMR_STOP (0)
#endif
/* The full SMR setting also includes internal clocking with no divisor,
* aysnchronous operation and multiprocessor disabled:
*/
#define SH1_SMR_VALUE (SH1_SMR_MODE|SH1_SMR_PARITY|SH1_SMR_STOP)
/* Clocking ***************************************************************/
/* The calculation of the BRR to achieve the desired BAUD is given by the
* following formula:
*
* brr = (f/(64*2**(2n-1)*b))-1
*
* Where:
*
* b = bit rate
* f = frequency (Hz)
* n = divider setting (0, 1, 2, 3)
*
* For n == 0, this simplifies to:
*
* brr = (f/(32*b))-1
*
* For example, if the processor is clocked at 10 MHz and 9600 is the
* desired BAUD:
*
* brr = 10,000,000 / (32 * 9600) - 1 = 31.552 (or 32 after rounding)
*/
#define SH1_DIVISOR (32 * SH1_SCI_BAUD)
#define SH1_BRR (((SH1_CLOCK + (SH1_DIVISOR/2))/SH1_DIVISOR)-1)
/**************************************************************************
* Private Types
**************************************************************************/
/**************************************************************************
* Private Function Prototypes
**************************************************************************/
/**************************************************************************
* Global Variables
**************************************************************************/
/**************************************************************************
* Private Variables
**************************************************************************/
/**************************************************************************
* Private Functions
**************************************************************************/
/**************************************************************************
* Name: up_txready
*
* Description:
* Return TRUE of the Transmit Data Register is empty
*
**************************************************************************/
#ifdef HAVE_CONSOLE
static inline int up_txready(void)
{
/* Check the TDRE bit in the SSR. 1=TDR is empty */
return ((getreg8(SH1_SCI_BASE + SH1_SCI_SSR_OFFSET) & SH1_SCISSR_TDRE) != 0);
}
#endif
/**************************************************************************
* Public Functions
**************************************************************************/
/**************************************************************************
* Name: up_lowputc
*
* Description:
* Output one byte on the serial console
*
**************************************************************************/
void up_lowputc(char ch)
{
#ifdef HAVE_CONSOLE
uint8_t ssr;
/* Wait until the TDR is avaible */
while (!up_txready());
/* Write the data to the TDR */
putreg8(ch, SH1_SCI_BASE + SH1_SCI_TDR_OFFSET);
/* Clear the TDRE bit in the SSR */
ssr = getreg8(SH1_SCI_BASE + SH1_SCI_SSR_OFFSET);
ssr &= ~SH1_SCISSR_TDRE;
putreg8(ssr, SH1_SCI_BASE + SH1_SCI_SSR_OFFSET);
#endif
}
/**************************************************************************
* Name: up_lowsetup
*
* Description:
* This performs basic initialization of the UART used for the serial
* console. Its purpose is to get the console output availabe as soon
* as possible.
*
**************************************************************************/
void up_lowsetup(void)
{
#if defined(HAVE_CONSOLE) && !defined(CONFIG_SUPPRESS_SCI_CONFIG)
uint8_t scr;
/* Disable the transmitter and receiver */
scr = getreg8(SH1_SCI_BASE + SH1_SCI_SCR_OFFSET);
scr &= ~(SH1_SCISCR_TE | SH1_SCISCR_RE);
putreg8(scr, SH1_SCI_BASE + SH1_SCI_SCR_OFFSET);
/* Set communication to be asynchronous with the configured number of data
* bits, parity, and stop bits. Use the internal clock (undivided)
*/
putreg8(SH1_SMR_VALUE, SH1_SCI_BASE + SH1_SCI_SMR_OFFSET);
/* Set the baud based on the configured console baud and configured
* system clock.
*/
putreg8(SH1_BRR, SH1_SCI_BASE + SH1_SCI_BRR_OFFSET);
/* Select the internal clock source as input */
scr &= ~SH1_SCISCR_CKEMASK;
putreg8(scr, SH1_SCI_BASE + SH1_SCI_SCR_OFFSET);
/* Wait a bit for the clocking to settle */
up_udelay(100);
/* Then enable the transmitter and reciever */
scr |= (SH1_SCISCR_TE | SH1_SCISCR_RE);
putreg8(scr, SH1_SCI_BASE + SH1_SCI_SCR_OFFSET);
#endif
}
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