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Diffstat (limited to 'cores/arduino/HardwareSerial.cpp')
| -rwxr-xr-x | cores/arduino/HardwareSerial.cpp | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp new file mode 100755 index 0000000..f8a959a --- /dev/null +++ b/cores/arduino/HardwareSerial.cpp @@ -0,0 +1,191 @@ +/* + HardwareSerial.cpp - Hardware serial library for Wiring + Copyright (c) 2006 Nicholas Zambetti. All right reserved. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Modified 23 November 2006 by David A. Mellis +*/ + +#include <stdio.h> +#include <string.h> +#include <inttypes.h> +#include "wiring.h" +#include "wiring_private.h" + +#include "HardwareSerial.h" + +// Define constants and variables for buffering incoming serial data. We're +// using a ring buffer (I think), in which rx_buffer_head is the index of the +// location to which to write the next incoming character and rx_buffer_tail +// is the index of the location from which to read. +#define RX_BUFFER_SIZE 128 + +struct ring_buffer { + unsigned char buffer[RX_BUFFER_SIZE]; + int head; + int tail; +}; + +ring_buffer rx_buffer = { { 0 }, 0, 0 }; + +#if defined(__AVR_ATmega1280__) +ring_buffer rx_buffer1 = { { 0 }, 0, 0 }; +ring_buffer rx_buffer2 = { { 0 }, 0, 0 }; +ring_buffer rx_buffer3 = { { 0 }, 0, 0 }; +#endif + +inline void store_char(unsigned char c, ring_buffer *rx_buffer) +{ + int i = (rx_buffer->head + 1) % RX_BUFFER_SIZE; + + // if we should be storing the received character into the location + // just before the tail (meaning that the head would advance to the + // current location of the tail), we're about to overflow the buffer + // and so we don't write the character or advance the head. + if (i != rx_buffer->tail) { + rx_buffer->buffer[rx_buffer->head] = c; + rx_buffer->head = i; + } +} + +#if defined(__AVR_ATmega1280__) + +SIGNAL(SIG_USART0_RECV) +{ + unsigned char c = UDR0; + store_char(c, &rx_buffer); +} + +SIGNAL(SIG_USART1_RECV) +{ + unsigned char c = UDR1; + store_char(c, &rx_buffer1); +} + +SIGNAL(SIG_USART2_RECV) +{ + unsigned char c = UDR2; + store_char(c, &rx_buffer2); +} + +SIGNAL(SIG_USART3_RECV) +{ + unsigned char c = UDR3; + store_char(c, &rx_buffer3); +} + +#else + +#if defined(__AVR_ATmega8__) +SIGNAL(SIG_UART_RECV) +#else +SIGNAL(USART_RX_vect) +#endif +{ +#if defined(__AVR_ATmega8__) + unsigned char c = UDR; +#else + unsigned char c = UDR0; +#endif + store_char(c, &rx_buffer); +} + +#endif + +// Constructors //////////////////////////////////////////////////////////////// + +HardwareSerial::HardwareSerial(ring_buffer *rx_buffer, + volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, + volatile uint8_t *ucsra, volatile uint8_t *ucsrb, + volatile uint8_t *udr, + uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre) +{ + _rx_buffer = rx_buffer; + _ubrrh = ubrrh; + _ubrrl = ubrrl; + _ucsra = ucsra; + _ucsrb = ucsrb; + _udr = udr; + _rxen = rxen; + _txen = txen; + _rxcie = rxcie; + _udre = udre; +} + +// Public Methods ////////////////////////////////////////////////////////////// + +void HardwareSerial::begin(long speed) +{ + *_ubrrh = ((F_CPU / 16 + speed / 2) / speed - 1) >> 8; + *_ubrrl = ((F_CPU / 16 + speed / 2) / speed - 1); + sbi(*_ucsrb, _rxen); + sbi(*_ucsrb, _txen); + sbi(*_ucsrb, _rxcie); +} + +uint8_t HardwareSerial::available(void) +{ + return (RX_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % RX_BUFFER_SIZE; +} + +int HardwareSerial::read(void) +{ + // if the head isn't ahead of the tail, we don't have any characters + if (_rx_buffer->head == _rx_buffer->tail) { + return -1; + } else { + unsigned char c = _rx_buffer->buffer[_rx_buffer->tail]; + _rx_buffer->tail = (_rx_buffer->tail + 1) % RX_BUFFER_SIZE; + return c; + } +} + +void HardwareSerial::flush() +{ + // don't reverse this or there may be problems if the RX interrupt + // occurs after reading the value of rx_buffer_head but before writing + // the value to rx_buffer_tail; the previous value of rx_buffer_head + // may be written to rx_buffer_tail, making it appear as if the buffer + // don't reverse this or there may be problems if the RX interrupt + // occurs after reading the value of rx_buffer_head but before writing + // the value to rx_buffer_tail; the previous value of rx_buffer_head + // may be written to rx_buffer_tail, making it appear as if the buffer + // were full, not empty. + _rx_buffer->head = _rx_buffer->tail; +} + +void HardwareSerial::write(uint8_t c) +{ + while (!((*_ucsra) & (1 << _udre))) + ; + + *_udr = c; +} + +// Preinstantiate Objects ////////////////////////////////////////////////////// + +#if defined(__AVR_ATmega8__) +HardwareSerial Serial(&rx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRE); +#else +HardwareSerial Serial(&rx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRE0); +#endif + +#if defined(__AVR_ATmega1280__) +HardwareSerial Serial1(&rx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UDR1, RXEN1, TXEN1, RXCIE1, UDRE1); +HardwareSerial Serial2(&rx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UDR2, RXEN2, TXEN2, RXCIE2, UDRE2); +HardwareSerial Serial3(&rx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UDR3, RXEN3, TXEN3, RXCIE3, UDRE3); +#endif + |