/******************************************************************************
* arch/avr/src/at90usb/at90usb_lowconsole.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 "at90usb_config.h"
#include <assert.h>
#include <debug.h>
#include <arch/irq.h>
#include <arch/board/board.h>
#include <avr/io.h>
#include "up_arch.h"
#include "up_internal.h"
#include "at90usb_internal.h"
/******************************************************************************
* Private Definitions
******************************************************************************/
/* Baud rate settings for normal and double speed settings */
#define AVR_NORMAL_UBRR1 \
((((BOARD_CPU_CLOCK / 16) + (CONFIG_USART1_BAUD / 2)) / (CONFIG_USART1_BAUD)) - 1)
#define AVR_DBLSPEED_UBRR1 \
((((BOARD_CPU_CLOCK / 8) + (CONFIG_USART1_BAUD / 2)) / (CONFIG_USART1_BAUD)) - 1)
/* Select normal or double speed baud settings. This is a trade-off between the
* sampling rate and the accuracy of the divisor for high baud rates.
*
* As examples, consider:
*
* BOARD_CPU_CLOCK=8MHz and BAUD=115200:
* AVR_NORMAL_UBRR1 = 4 (rounded), actual baud = 125,000
* AVR_DBLSPEED_UBRR1 = 9 (rounded), actual baud = 111,111
*
* BOARD_CPU_CLOCK=8MHz and BAUD=9600:
* AVR_NORMAL_UBRR1 = 52 (rounded), actual baud = 9615
* AVR_DBLSPEED_UBRR1 = 104 (rounded), actual baud = 9615
*/
#undef UART1_DOUBLE_SPEED
#if BOARD_CPU_CLOCK <= 4000000
# if CONFIG_USART1_BAUD <= 9600
# define AVR_UBRR1 AVR_NORMAL_UBRR1
# else
# define AVR_UBRR1 AVR_DBLSPEED_UBRR1
# define UART1_DOUBLE_SPEED 1
# endif
#elif BOARD_CPU_CLOCK <= 8000000
# if CONFIG_USART1_BAUD <= 19200
# define AVR_UBRR1 AVR_NORMAL_UBRR1
# else
# define AVR_UBRR1 AVR_DBLSPEED_UBRR1
# define UART1_DOUBLE_SPEED 1
# endif
#elif BOARD_CPU_CLOCK <= 12000000
# if CONFIG_USART1_BAUD <= 28800
# define AVR_UBRR1 AVR_NORMAL_UBRR1
# else
# define AVR_UBRR1 AVR_DBLSPEED_UBRR1
# define UART1_DOUBLE_SPEED 1
# endif
#else
# if CONFIG_USART1_BAUD <= 38400
# define AVR_UBRR1 AVR_NORMAL_UBRR1
# else
# define AVR_UBRR1 AVR_DBLSPEED_UBRR1
# define UART1_DOUBLE_SPEED 1
# endif
#endif
/******************************************************************************
* Private Types
******************************************************************************/
/******************************************************************************
* Private Function Prototypes
******************************************************************************/
/******************************************************************************
* Global Variables
******************************************************************************/
/******************************************************************************
* Private Variables
******************************************************************************/
/******************************************************************************
* Private Functions
******************************************************************************/
/******************************************************************************
* Public Functions
******************************************************************************/
/******************************************************************************
* Name: usart1_reset
*
* Description:
* Reset a USART.
*
******************************************************************************/
#ifdef HAVE_USART_DEVICE
void usart1_reset(void)
{
UCSR1A = 0;
UCSR1B = 0;
UCSR1C = 0;
DDRD &= ~(1 << 3);
PORTD &= ~(1 << 2);
UBRR1 = 0;
}
#endif
/******************************************************************************
* Name: usart1_configure
*
* Description:
* Configure USART1.
*
******************************************************************************/
#ifdef HAVE_USART_DEVICE
void usart1_configure(void)
{
uint8_t ucsr1b;
uint8_t ucsr1c;
/* Select normal or double speed. */
#ifdef UART1_DOUBLE_SPEED
UCSR1A = (1 << U2X1);
#else
UCSR1A = 0;
#endif
/* Select baud, parity, nubmer of bits, stop bits, etc. */
ucsr1b = ((1 << TXEN1) | (1 << RXEN1));
ucsr1c = 0;
/* Select parity */
#if CONFIG_USART1_PARITY == 1
ucsr1c |= (UPM11 | UPM10); /* Odd parity */
#else
ucsr1c |= UPM11; /* Even parity */
#endif
/* 1 or 2 stop bits */
#if defined(CONFIG_USART1_2STOP) && CONFIG_USART1_2STOP > 0
ucsr1c |= USBS1; /* Two stop bits */
#endif
/* Word size */
#if CONFIG_USART1_BITS == 5
#elif CONFIG_USART1_BITS == 6
ucsr1c |= UCSZ10;
#elif CONFIG_USART1_BITS == 7
ucsr1c |= UCSZ11;
#elif CONFIG_USART1_BITS == 8
ucsr1c |= (UCSZ10 | UCSZ11);
#elif CONFIG_USART1_BITS == 9
ucsr1c |= (UCSZ10 | UCSZ11);
ucsr1b |= UCSZ12;
#else
# error "Unsupported word size"
#endif
UCSR1B = ucsr1b;
UCSR1C = ucsr1c;
/* Configure pin */
DDRD |= (1 << 3);
PORTD |= (1 << 2);
/* Set the baud rate divisor */
UBRR1 = AVR_UBRR1;
}
#endif
/******************************************************************************
* Name: up_consoleinit
*
* Description:
* Initialize a console for debug output. This function is called very
* early in the intialization sequence to configure the serial console uart
* (only).
*
******************************************************************************/
void up_consoleinit(void)
{
#ifdef HAVE_SERIAL_CONSOLE
usart1_configure();
#endif
}
/******************************************************************************
* Name: up_lowputc
*
* Description:
* Output one byte on the serial console
*
******************************************************************************/
void up_lowputc(char ch)
{
#ifdef HAVE_SERIAL_CONSOLE
while ((UCSR1A & (1 << UDRE1)) == 0);
UDR1 = ch;
#endif
}
