Steve Karg
465 lines
12 KiB
C
465 lines
12 KiB
C
/**
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* \file
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*
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* \brief USART driver for AVR XMEGA.
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*
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* Copyright (c) 2009-2012 Atmel Corporation. All rights reserved.
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*
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* \asf_license_start
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*
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* \page License
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. The name of Atmel may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* 4. This software may only be redistributed and used in connection with an
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* Atmel microcontroller product.
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*
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* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* \asf_license_stop
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*
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*/
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#include <stdint.h>
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#include "compiler.h"
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#include "usart.h"
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#include "sysclk.h"
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#include "ioport.h"
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#include "status_codes.h"
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/*
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* Fix XMEGA header files
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* USART.CTRLC bit masks and bit positions
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*/
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#ifndef USART_UCPHA_bm
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# define USART_UCPHA_bm 0x02
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#endif
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#ifndef USART_DORD_bm
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# define USART_DORD_bm 0x04
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#endif
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/**
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* \brief Initialize USART in RS232 mode.
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*
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* This function initializes the USART module in RS232 mode using the
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* usart_rs232_options_t configuration structure and CPU frequency.
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*
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* \param usart The USART module.
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* \param opt The RS232 configuration option.
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*
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* \retval true if the initialization was successfull
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* \retval false if the initialization failed (error in baud rate calculation)
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*/
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bool usart_init_rs232(USART_t *usart, const usart_rs232_options_t *opt)
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{
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bool result;
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sysclk_enable_peripheral_clock(usart);
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usart_set_mode(usart, USART_CMODE_ASYNCHRONOUS_gc);
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usart_format_set(usart, opt->charlength, opt->paritytype,
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opt->stopbits);
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result = usart_set_baudrate(usart, opt->baudrate, sysclk_get_per_hz());
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usart_tx_enable(usart);
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usart_rx_enable(usart);
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return result;
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}
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/**
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* \brief Initialize USART in SPI master mode.
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*
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* This function initializes the USART module in SPI master mode using the
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* usart_spi_options_t configuration structure and CPU frequency.
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*
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* \param usart The USART module.
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* \param opt The RS232 configuration option.
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*/
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void usart_init_spi(USART_t *usart, const usart_spi_options_t *opt)
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{
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ioport_pin_t sck_pin;
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bool invert_sck;
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sysclk_enable_peripheral_clock(usart);
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usart_rx_disable(usart);
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/* configure Clock polarity using INVEN bit of the correct SCK I/O port **/
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invert_sck = (opt->spimode == 2) || (opt->spimode == 3);
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UNUSED(invert_sck);
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#ifdef USARTC0
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if ((uint16_t)usart == (uint16_t)&USARTC0) {
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# ifdef PORT_USART0_bm
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if (PORTC.REMAP & PORT_USART0_bm) {
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sck_pin = IOPORT_CREATE_PIN(PORTC, 5);
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} else {
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sck_pin = IOPORT_CREATE_PIN(PORTC, 1);
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}
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# else
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sck_pin = IOPORT_CREATE_PIN(PORTC, 1);
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# endif
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}
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#endif
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#ifdef USARTC1
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if ((uint16_t)usart == (uint16_t)&USARTC1) {
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sck_pin = IOPORT_CREATE_PIN(PORTC, 5);
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}
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#endif
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#ifdef USARTD0
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if ((uint16_t)usart == (uint16_t)&USARTD0) {
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# ifdef PORT_USART0_bm
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if (PORTD.REMAP & PORT_USART0_bm) {
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sck_pin = IOPORT_CREATE_PIN(PORTD, 5);
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} else {
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sck_pin = IOPORT_CREATE_PIN(PORTD, 1);
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}
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# else
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sck_pin = IOPORT_CREATE_PIN(PORTD, 1);
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# endif
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}
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#endif
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#ifdef USARTD1
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if ((uint16_t)usart == (uint16_t)&USARTD1) {
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sck_pin = IOPORT_CREATE_PIN(PORTD, 5);
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}
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#endif
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#ifdef USARTE0
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if ((uint16_t)usart == (uint16_t)&USARTE0) {
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# ifdef PORT_USART0_bm
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if(PORTE.REMAP & PORT_USART0_bm) {
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sck_pin = IOPORT_CREATE_PIN(PORTE, 5);
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} else {
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sck_pin = IOPORT_CREATE_PIN(PORTE, 1);
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}
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# else
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sck_pin = IOPORT_CREATE_PIN(PORTE, 1);
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# endif
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}
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#endif
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#ifdef USARTE1
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if ((uint16_t)usart == (uint16_t)&USARTE1) {
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sck_pin = IOPORT_CREATE_PIN(PORTE, 5);
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}
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#endif
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#ifdef USARTF0
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if ((uint16_t)usart == (uint16_t)&USARTF0) {
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# ifdef PORT_USART0_bm
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if(PORTF.REMAP & PORT_USART0_bm) {
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sck_pin = IOPORT_CREATE_PIN(PORTF, 5);
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} else {
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sck_pin = IOPORT_CREATE_PIN(PORTF, 1);
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}
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# else
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sck_pin = IOPORT_CREATE_PIN(PORTF, 1);
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# endif
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}
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#endif
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#ifdef USARTF1
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if ((uint16_t)usart == (uint16_t)&USARTF1) {
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sck_pin = IOPORT_CREATE_PIN(PORTF, 5);
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}
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#endif
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/* Configure the USART output pin */
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ioport_set_pin_dir(sck_pin, IOPORT_DIR_OUTPUT);
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ioport_set_pin_mode(sck_pin,
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IOPORT_MODE_TOTEM | (invert_sck? IOPORT_MODE_INVERT_PIN : 0));
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ioport_set_pin_level(sck_pin, IOPORT_PIN_LEVEL_HIGH);
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usart_set_mode(usart, USART_CMODE_MSPI_gc);
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if (opt->spimode == 1 || opt->spimode == 3) {
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usart->CTRLC |= USART_UCPHA_bm;
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} else {
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usart->CTRLC &= ~USART_UCPHA_bm;
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}
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if (opt->data_order) {
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(usart)->CTRLC |= USART_DORD_bm;
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} else {
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(usart)->CTRLC &= ~USART_DORD_bm;
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}
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usart_spi_set_baudrate(usart, opt->baudrate, sysclk_get_per_hz());
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usart_tx_enable(usart);
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usart_rx_enable(usart);
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}
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/**
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* \brief Send a data with the USART module
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*
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* This function outputs a data using the USART module.
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*
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* \param usart The USART module.
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* \param c The data to send.
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*
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* \return STATUS_OK
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*/
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status_code_t usart_putchar(USART_t *usart, uint8_t c)
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{
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while (usart_data_register_is_empty(usart) == false) {
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}
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(usart)->DATA = c;
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return STATUS_OK;
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}
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/**
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* \brief Receive a data with the USART module
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*
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* This function returns the received data from the USART module.
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*
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* \param usart The USART module.
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*
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* \return The received data.
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*/
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uint8_t usart_getchar(USART_t *usart)
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{
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while (usart_rx_is_complete(usart) == false) {
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}
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return ((uint8_t)(usart)->DATA);
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}
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/**
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* \brief Get the offset for lookup in the baudrate table
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*
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* \param baud The requested baudrate
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*
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* \return The baudrate offset in PROGMEM table
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* \retval USART_BAUD_UNDEFINED for baudrates not in lookup table
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*/
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static uint8_t usart_get_baud_offset(uint32_t baud)
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{
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switch (baud) {
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case 1200:
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return (uint8_t)USART_BAUD_1200;
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case 2400:
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return (uint8_t)USART_BAUD_2400;
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case 4800:
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return (uint8_t)USART_BAUD_4800;
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case 9600:
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return (uint8_t)USART_BAUD_9600;
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case 19200:
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return (uint8_t)USART_BAUD_19200;
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case 38400:
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return (uint8_t)USART_BAUD_38400;
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case 57600:
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return (uint8_t)USART_BAUD_57600;
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default:
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return (uint8_t)USART_BAUD_UNDEFINED;
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}
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}
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/**
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* \brief Set the baudrate by setting the BSEL and BSCALE values in the USART
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*
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* This function sets the selected BSEL and BSCALE value in the BAUDCTRL
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* registers with BSCALE 0. For calculation options, see table 21-1 in XMEGA A
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* manual.
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*
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* \param usart The USART module.
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* \param bsel Calculated BSEL value.
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* \param bscale Calculated BSEL value.
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*
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*/
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void usart_set_bsel_bscale_value(USART_t *usart, uint16_t bsel, uint8_t bscale)
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{
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(usart)->BAUDCTRLA = (uint8_t)(bsel);
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(usart)->BAUDCTRLB = (uint8_t)(((bsel >> 8) & 0X0F) | (bscale << 4));
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}
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/**
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* \brief Set the baudrate using precalculated BAUDCTRL values from PROGMEM
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*
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* \note This function only works for cpu_hz 2Mhz or 32Mhz and baudrate values
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* 1200, 2400, 4800, 9600, 19200, 38400 and 57600.
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*
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* \param usart The USART module.
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* \param baud The baudrate.
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* \param cpu_hz The CPU frequency.
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*
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*/
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void usart_set_baudrate_precalculated(USART_t *usart, uint32_t baud,
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uint32_t cpu_hz)
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{
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uint8_t baud_offset;
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uint16_t baudctrl = 0;
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baud_offset = usart_get_baud_offset(baud);
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if (cpu_hz == 2000000UL) {
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baudctrl = PROGMEM_READ_WORD(baudctrl_2mhz + baud_offset);
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} else if (cpu_hz == 32000000UL) {
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baudctrl = PROGMEM_READ_WORD(baudctrl_32mhz + baud_offset);
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} else {
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/* Error, system clock speed or USART baud rate is not supported
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* by the look-up table */
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Assert(false);
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}
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if (baud_offset != USART_BAUD_UNDEFINED) {
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(usart)->BAUDCTRLB = (uint8_t)((uint16_t)baudctrl);
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(usart)->BAUDCTRLA = (uint8_t)((uint16_t)baudctrl >> 8);
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}
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}
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/**
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* \brief Set the baudrate value in the USART module
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*
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* This function sets the baudrate register with scaling regarding the CPU
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* frequency and makes sure the baud rate is supported by the hardware.
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* The function can be used if you don't want to calculate the settings
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* yourself or changes to baudrate at runtime is required.
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*
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* \param usart The USART module.
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* \param baud The baudrate.
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* \param cpu_hz The CPU frequency.
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*
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* \retval true if the hardware supports the baud rate
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* \retval false if the hardware does not support the baud rate (i.e. it's
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* either too high or too low.)
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*/
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bool usart_set_baudrate(USART_t *usart, uint32_t baud, uint32_t cpu_hz)
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{
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int8_t exp;
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uint32_t div;
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uint32_t limit;
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uint32_t ratio;
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uint32_t min_rate;
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uint32_t max_rate;
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/*
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* Check if the hardware supports the given baud rate
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*/
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/* 8 = (2^0) * 8 * (2^0) = (2^BSCALE_MIN) * 8 * (BSEL_MIN) */
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max_rate = cpu_hz / 8;
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/* 4194304 = (2^7) * 8 * (2^12) = (2^BSCALE_MAX) * 8 * (BSEL_MAX+1) */
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min_rate = cpu_hz / 4194304;
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if (!((usart)->CTRLB & USART_CLK2X_bm)) {
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max_rate /= 2;
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min_rate /= 2;
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}
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if ((baud > max_rate) || (baud < min_rate)) {
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return false;
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}
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/* Check if double speed is enabled. */
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if (!((usart)->CTRLB & USART_CLK2X_bm)) {
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baud *= 2;
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}
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/* Find the lowest possible exponent. */
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limit = 0xfffU >> 4;
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ratio = cpu_hz / baud;
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for (exp = -7; exp < 7; exp++) {
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if (ratio < limit) {
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break;
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}
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limit <<= 1;
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if (exp < -3) {
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limit |= 1;
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}
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}
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/*
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* Depending on the value of exp, scale either the input frequency or
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* the target baud rate. By always scaling upwards, we never introduce
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* any additional inaccuracy.
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*
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* We are including the final divide-by-8 (aka. right-shift-by-3) in
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* this operation as it ensures that we never exceeed 2**32 at any
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* point.
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*
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* The formula for calculating BSEL is slightly different when exp is
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* negative than it is when exp is positive.
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*/
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if (exp < 0) {
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/* We are supposed to subtract 1, then apply BSCALE. We want to
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* apply BSCALE first, so we need to turn everything inside the
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* parenthesis into a single fractional expression.
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*/
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cpu_hz -= 8 * baud;
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/* If we end up with a left-shift after taking the final
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* divide-by-8 into account, do the shift before the divide.
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* Otherwise, left-shift the denominator instead (effectively
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* resulting in an overall right shift.)
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*/
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if (exp <= -3) {
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div = ((cpu_hz << (-exp - 3)) + baud / 2) / baud;
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} else {
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baud <<= exp + 3;
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div = (cpu_hz + baud / 2) / baud;
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}
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} else {
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/* We will always do a right shift in this case, but we need to
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* shift three extra positions because of the divide-by-8.
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*/
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baud <<= exp + 3;
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div = (cpu_hz + baud / 2) / baud - 1;
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}
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(usart)->BAUDCTRLB = (uint8_t)(((div >> 8) & 0X0F) | (exp << 4));
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(usart)->BAUDCTRLA = (uint8_t)div;
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return true;
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}
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/**
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* \brief Set the baudrate value in the USART_SPI module
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*
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* This function sets the baudrate register regarding the CPU frequency.
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*
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* \param usart The USART(SPI) module.
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* \param baud The baudrate.
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* \param cpu_hz The CPU frequency.
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*/
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void usart_spi_set_baudrate(USART_t *usart, uint32_t baud, uint32_t cpu_hz)
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{
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uint16_t bsel_value;
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/* Check if baudrate is less than the maximim limit specified in
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* datasheet */
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if (baud < (cpu_hz / 2)) {
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bsel_value = (cpu_hz / (baud * 2)) - 1;
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} else {
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/* If baudrate is not within the specfication in datasheet,
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* assign maximum baudrate possible for the current CPU frequency */
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bsel_value = 0;
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}
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(usart)->BAUDCTRLB = (uint8_t)((~USART_BSCALE_gm) & (bsel_value >> 8));
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(usart)->BAUDCTRLA = (uint8_t)(bsel_value);
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}
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