diff options
Diffstat (limited to 'cores/arduino/HardwareSerial.cpp')
| -rw-r--r-- | cores/arduino/HardwareSerial.cpp | 495 |
1 files changed, 112 insertions, 383 deletions
diff --git a/cores/arduino/HardwareSerial.cpp b/cores/arduino/HardwareSerial.cpp index eb2365f..81b406a 100644 --- a/cores/arduino/HardwareSerial.cpp +++ b/cores/arduino/HardwareSerial.cpp @@ -19,6 +19,7 @@ Modified 23 November 2006 by David A. Mellis Modified 28 September 2010 by Mark Sproul Modified 14 August 2012 by Alarus + Modified 3 December 2013 by Matthijs Kooijman */ #include <stdlib.h> @@ -26,483 +27,211 @@ #include <string.h> #include <inttypes.h> #include "Arduino.h" -#include "wiring_private.h" - -// this next line disables the entire HardwareSerial.cpp, -// this is so I can support Attiny series and any other chip without a uart -#if defined(UBRRH) || defined(UBRR0H) || defined(UBRR1H) || defined(UBRR2H) || defined(UBRR3H) #include "HardwareSerial.h" +#include "HardwareSerial_private.h" -/* - * on ATmega8, the uart and its bits are not numbered, so there is no "TXC0" - * definition. - */ -#if !defined(TXC0) -#if defined(TXC) -#define TXC0 TXC -#elif defined(TXC1) -// Some devices have uart1 but no uart0 -#define TXC0 TXC1 -#else -#error TXC0 not definable in HardwareSerial.h -#endif -#endif - -// Define constants and variables for buffering incoming serial data. We're -// using a ring buffer (I think), in which head is the index of the location -// to which to write the next incoming character and tail is the index of the -// location from which to read. -#if (RAMEND < 1000) - #define SERIAL_BUFFER_SIZE 16 -#else - #define SERIAL_BUFFER_SIZE 64 -#endif - -struct ring_buffer -{ - unsigned char buffer[SERIAL_BUFFER_SIZE]; - volatile unsigned int head; - volatile unsigned int tail; -}; - -#if defined(USBCON) - ring_buffer rx_buffer = { { 0 }, 0, 0}; - ring_buffer tx_buffer = { { 0 }, 0, 0}; -#endif -#if defined(UBRRH) || defined(UBRR0H) - ring_buffer rx_buffer = { { 0 }, 0, 0 }; - ring_buffer tx_buffer = { { 0 }, 0, 0 }; -#endif -#if defined(UBRR1H) - ring_buffer rx_buffer1 = { { 0 }, 0, 0 }; - ring_buffer tx_buffer1 = { { 0 }, 0, 0 }; -#endif -#if defined(UBRR2H) - ring_buffer rx_buffer2 = { { 0 }, 0, 0 }; - ring_buffer tx_buffer2 = { { 0 }, 0, 0 }; -#endif -#if defined(UBRR3H) - ring_buffer rx_buffer3 = { { 0 }, 0, 0 }; - ring_buffer tx_buffer3 = { { 0 }, 0, 0 }; -#endif - -inline void store_char(unsigned char c, ring_buffer *buffer) -{ - int i = (unsigned int)(buffer->head + 1) % SERIAL_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 != buffer->tail) { - buffer->buffer[buffer->head] = c; - buffer->head = i; - } -} - -#if !defined(USART0_RX_vect) && defined(USART1_RX_vect) -// do nothing - on the 32u4 the first USART is USART1 -#else -#if !defined(USART_RX_vect) && !defined(USART0_RX_vect) && \ - !defined(USART_RXC_vect) - #error "Don't know what the Data Received vector is called for the first UART" -#else +// this next line disables the entire HardwareSerial.cpp, +// this is so I can support Attiny series and any other chip without a uart +#if defined(HAVE_HWSERIAL0) || defined(HAVE_HWSERIAL1) || defined(HAVE_HWSERIAL2) || defined(HAVE_HWSERIAL3) + +// SerialEvent functions are weak, so when the user doesn't define them, +// the linker just sets their address to 0 (which is checked below). +// The Serialx_available is just a wrapper around Serialx.available(), +// but we can refer to it weakly so we don't pull in the entire +// HardwareSerial instance if the user doesn't also refer to it. +#if defined(HAVE_HWSERIAL0) void serialEvent() __attribute__((weak)); - void serialEvent() {} - #define serialEvent_implemented -#if defined(USART_RX_vect) - ISR(USART_RX_vect) -#elif defined(USART0_RX_vect) - ISR(USART0_RX_vect) -#elif defined(USART_RXC_vect) - ISR(USART_RXC_vect) // ATmega8 -#endif - { - #if defined(UDR0) - if (bit_is_clear(UCSR0A, UPE0)) { - unsigned char c = UDR0; - store_char(c, &rx_buffer); - } else { - unsigned char c = UDR0; - }; - #elif defined(UDR) - if (bit_is_clear(UCSRA, PE)) { - unsigned char c = UDR; - store_char(c, &rx_buffer); - } else { - unsigned char c = UDR; - }; - #else - #error UDR not defined - #endif - } -#endif + bool Serial0_available() __attribute__((weak)); #endif -#if defined(USART1_RX_vect) +#if defined(HAVE_HWSERIAL1) void serialEvent1() __attribute__((weak)); - void serialEvent1() {} - #define serialEvent1_implemented - ISR(USART1_RX_vect) - { - if (bit_is_clear(UCSR1A, UPE1)) { - unsigned char c = UDR1; - store_char(c, &rx_buffer1); - } else { - unsigned char c = UDR1; - }; - } + bool Serial1_available() __attribute__((weak)); #endif -#if defined(USART2_RX_vect) && defined(UDR2) +#if defined(HAVE_HWSERIAL2) void serialEvent2() __attribute__((weak)); - void serialEvent2() {} - #define serialEvent2_implemented - ISR(USART2_RX_vect) - { - if (bit_is_clear(UCSR2A, UPE2)) { - unsigned char c = UDR2; - store_char(c, &rx_buffer2); - } else { - unsigned char c = UDR2; - }; - } + bool Serial2_available() __attribute__((weak)); #endif -#if defined(USART3_RX_vect) && defined(UDR3) +#if defined(HAVE_HWSERIAL3) void serialEvent3() __attribute__((weak)); - void serialEvent3() {} - #define serialEvent3_implemented - ISR(USART3_RX_vect) - { - if (bit_is_clear(UCSR3A, UPE3)) { - unsigned char c = UDR3; - store_char(c, &rx_buffer3); - } else { - unsigned char c = UDR3; - }; - } + bool Serial3_available() __attribute__((weak)); #endif void serialEventRun(void) { -#ifdef serialEvent_implemented - if (Serial.available()) serialEvent(); +#if defined(HAVE_HWSERIAL0) + if (Serial0_available && serialEvent && Serial0_available()) serialEvent(); #endif -#ifdef serialEvent1_implemented - if (Serial1.available()) serialEvent1(); +#if defined(HAVE_HWSERIAL1) + if (Serial1_available && serialEvent1 && Serial1_available()) serialEvent1(); #endif -#ifdef serialEvent2_implemented - if (Serial2.available()) serialEvent2(); +#if defined(HAVE_HWSERIAL2) + if (Serial2_available && serialEvent2 && Serial2_available()) serialEvent2(); #endif -#ifdef serialEvent3_implemented - if (Serial3.available()) serialEvent3(); +#if defined(HAVE_HWSERIAL3) + if (Serial3_available && serialEvent2 && Serial3_available()) serialEvent3(); #endif } +// Actual interrupt handlers ////////////////////////////////////////////////////////////// -#if !defined(USART0_UDRE_vect) && defined(USART1_UDRE_vect) -// do nothing - on the 32u4 the first USART is USART1 -#else -#if !defined(UART0_UDRE_vect) && !defined(UART_UDRE_vect) && !defined(USART0_UDRE_vect) && !defined(USART_UDRE_vect) - #error "Don't know what the Data Register Empty vector is called for the first UART" -#else -#if defined(UART0_UDRE_vect) -ISR(UART0_UDRE_vect) -#elif defined(UART_UDRE_vect) -ISR(UART_UDRE_vect) -#elif defined(USART0_UDRE_vect) -ISR(USART0_UDRE_vect) -#elif defined(USART_UDRE_vect) -ISR(USART_UDRE_vect) -#endif +void HardwareSerial::_tx_udr_empty_irq(void) { - if (tx_buffer.head == tx_buffer.tail) { - // Buffer empty, so disable interrupts -#if defined(UCSR0B) - cbi(UCSR0B, UDRIE0); -#else - cbi(UCSRB, UDRIE); -#endif - } - else { - // There is more data in the output buffer. Send the next byte - unsigned char c = tx_buffer.buffer[tx_buffer.tail]; - tx_buffer.tail = (tx_buffer.tail + 1) % SERIAL_BUFFER_SIZE; - - #if defined(UDR0) - UDR0 = c; - #elif defined(UDR) - UDR = c; - #else - #error UDR not defined - #endif - } -} -#endif -#endif + // If interrupts are enabled, there must be more data in the output + // buffer. Send the next byte + unsigned char c = _tx_buffer[_tx_buffer_tail]; + _tx_buffer_tail = (_tx_buffer_tail + 1) % SERIAL_BUFFER_SIZE; -#ifdef USART1_UDRE_vect -ISR(USART1_UDRE_vect) -{ - if (tx_buffer1.head == tx_buffer1.tail) { - // Buffer empty, so disable interrupts - cbi(UCSR1B, UDRIE1); - } - else { - // There is more data in the output buffer. Send the next byte - unsigned char c = tx_buffer1.buffer[tx_buffer1.tail]; - tx_buffer1.tail = (tx_buffer1.tail + 1) % SERIAL_BUFFER_SIZE; - - UDR1 = c; - } -} -#endif + *_udr = c; -#ifdef USART2_UDRE_vect -ISR(USART2_UDRE_vect) -{ - if (tx_buffer2.head == tx_buffer2.tail) { - // Buffer empty, so disable interrupts - cbi(UCSR2B, UDRIE2); - } - else { - // There is more data in the output buffer. Send the next byte - unsigned char c = tx_buffer2.buffer[tx_buffer2.tail]; - tx_buffer2.tail = (tx_buffer2.tail + 1) % SERIAL_BUFFER_SIZE; - - UDR2 = c; - } -} -#endif + // clear the TXC bit -- "can be cleared by writing a one to its bit + // location". This makes sure flush() won't return until the bytes + // actually got written + sbi(*_ucsra, TXC0); -#ifdef USART3_UDRE_vect -ISR(USART3_UDRE_vect) -{ - if (tx_buffer3.head == tx_buffer3.tail) { - // Buffer empty, so disable interrupts - cbi(UCSR3B, UDRIE3); - } - else { - // There is more data in the output buffer. Send the next byte - unsigned char c = tx_buffer3.buffer[tx_buffer3.tail]; - tx_buffer3.tail = (tx_buffer3.tail + 1) % SERIAL_BUFFER_SIZE; - - UDR3 = c; + if (_tx_buffer_head == _tx_buffer_tail) { + // Buffer empty, so disable interrupts + cbi(*_ucsrb, UDRIE0); } } -#endif - - -// Constructors //////////////////////////////////////////////////////////////// - -HardwareSerial::HardwareSerial(ring_buffer *rx_buffer, ring_buffer *tx_buffer, - volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, - volatile uint8_t *ucsra, volatile uint8_t *ucsrb, - volatile uint8_t *ucsrc, volatile uint8_t *udr, - uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udrie, uint8_t u2x) -{ - _rx_buffer = rx_buffer; - _tx_buffer = tx_buffer; - _ubrrh = ubrrh; - _ubrrl = ubrrl; - _ucsra = ucsra; - _ucsrb = ucsrb; - _ucsrc = ucsrc; - _udr = udr; - _rxen = rxen; - _txen = txen; - _rxcie = rxcie; - _udrie = udrie; - _u2x = u2x; -} // Public Methods ////////////////////////////////////////////////////////////// -void HardwareSerial::begin(unsigned long baud) -{ - uint16_t baud_setting; - bool use_u2x = true; - -#if F_CPU == 16000000UL - // hardcoded exception for compatibility with the bootloader shipped - // with the Duemilanove and previous boards and the firmware on the 8U2 - // on the Uno and Mega 2560. - if (baud == 57600) { - use_u2x = false; - } -#endif - -try_again: - - if (use_u2x) { - *_ucsra = 1 << _u2x; - baud_setting = (F_CPU / 4 / baud - 1) / 2; - } else { - *_ucsra = 0; - baud_setting = (F_CPU / 8 / baud - 1) / 2; - } - - if ((baud_setting > 4095) && use_u2x) - { - use_u2x = false; - goto try_again; - } - - // assign the baud_setting, a.k.a. ubbr (USART Baud Rate Register) - *_ubrrh = baud_setting >> 8; - *_ubrrl = baud_setting; - - transmitting = false; - - sbi(*_ucsrb, _rxen); - sbi(*_ucsrb, _txen); - sbi(*_ucsrb, _rxcie); - cbi(*_ucsrb, _udrie); -} - void HardwareSerial::begin(unsigned long baud, byte config) { - uint16_t baud_setting; - uint8_t current_config; - bool use_u2x = true; - -#if F_CPU == 16000000UL - // hardcoded exception for compatibility with the bootloader shipped - // with the Duemilanove and previous boards and the firmware on the 8U2 - // on the Uno and Mega 2560. - if (baud == 57600) { - use_u2x = false; - } -#endif + // Try u2x mode first + uint16_t baud_setting = (F_CPU / 4 / baud - 1) / 2; + *_ucsra = 1 << U2X0; -try_again: - - if (use_u2x) { - *_ucsra = 1 << _u2x; - baud_setting = (F_CPU / 4 / baud - 1) / 2; - } else { + // hardcoded exception for 57600 for compatibility with the bootloader + // shipped with the Duemilanove and previous boards and the firmware + // on the 8U2 on the Uno and Mega 2560. Also, The baud_setting cannot + // be > 4095, so switch back to non-u2x mode if the baud rate is too + // low. + if (((F_CPU == 16000000UL) && (baud == 57600)) || (baud_setting >4095)) + { *_ucsra = 0; baud_setting = (F_CPU / 8 / baud - 1) / 2; } - - if ((baud_setting > 4095) && use_u2x) - { - use_u2x = false; - goto try_again; - } // assign the baud_setting, a.k.a. ubbr (USART Baud Rate Register) *_ubrrh = baud_setting >> 8; *_ubrrl = baud_setting; + _written = false; + //set the data bits, parity, and stop bits #if defined(__AVR_ATmega8__) config |= 0x80; // select UCSRC register (shared with UBRRH) #endif *_ucsrc = config; - sbi(*_ucsrb, _rxen); - sbi(*_ucsrb, _txen); - sbi(*_ucsrb, _rxcie); - cbi(*_ucsrb, _udrie); + sbi(*_ucsrb, RXEN0); + sbi(*_ucsrb, TXEN0); + sbi(*_ucsrb, RXCIE0); + cbi(*_ucsrb, UDRIE0); } void HardwareSerial::end() { // wait for transmission of outgoing data - while (_tx_buffer->head != _tx_buffer->tail) + while (_tx_buffer_head != _tx_buffer_tail) ; - cbi(*_ucsrb, _rxen); - cbi(*_ucsrb, _txen); - cbi(*_ucsrb, _rxcie); - cbi(*_ucsrb, _udrie); + cbi(*_ucsrb, RXEN0); + cbi(*_ucsrb, TXEN0); + cbi(*_ucsrb, RXCIE0); + cbi(*_ucsrb, UDRIE0); // clear any received data - _rx_buffer->head = _rx_buffer->tail; + _rx_buffer_head = _rx_buffer_tail; } int HardwareSerial::available(void) { - return (unsigned int)(SERIAL_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % SERIAL_BUFFER_SIZE; + return (unsigned int)(SERIAL_BUFFER_SIZE + _rx_buffer_head - _rx_buffer_tail) % SERIAL_BUFFER_SIZE; } int HardwareSerial::peek(void) { - if (_rx_buffer->head == _rx_buffer->tail) { + if (_rx_buffer_head == _rx_buffer_tail) { return -1; } else { - return _rx_buffer->buffer[_rx_buffer->tail]; + return _rx_buffer[_rx_buffer_tail]; } } 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) { + if (_rx_buffer_head == _rx_buffer_tail) { return -1; } else { - unsigned char c = _rx_buffer->buffer[_rx_buffer->tail]; - _rx_buffer->tail = (unsigned int)(_rx_buffer->tail + 1) % SERIAL_BUFFER_SIZE; + unsigned char c = _rx_buffer[_rx_buffer_tail]; + _rx_buffer_tail = (unsigned int)(_rx_buffer_tail + 1) % SERIAL_BUFFER_SIZE; return c; } } void HardwareSerial::flush() { - // UDR is kept full while the buffer is not empty, so TXC triggers when EMPTY && SENT - while (transmitting && ! (*_ucsra & _BV(TXC0))); - transmitting = false; + // If we have never written a byte, no need to flush. This special + // case is needed since there is no way to force the TXC (transmit + // complete) bit to 1 during initialization + if (!_written) + return; + + while (bit_is_set(*_ucsrb, UDRIE0) || bit_is_clear(*_ucsra, TXC0)) { + if (bit_is_clear(SREG, SREG_I) && bit_is_set(*_ucsrb, UDRIE0)) + // Interrupts are globally disabled, but the DR empty + // interrupt should be enabled, so poll the DR empty flag to + // prevent deadlock + if (bit_is_set(*_ucsra, UDRE0)) + _tx_udr_empty_irq(); + } + // If we get here, nothing is queued anymore (DRIE is disabled) and + // the hardware finished tranmission (TXC is set). } size_t HardwareSerial::write(uint8_t c) { - int i = (_tx_buffer->head + 1) % SERIAL_BUFFER_SIZE; + // If the buffer and the data register is empty, just write the byte + // to the data register and be done. This shortcut helps + // significantly improve the effective datarate at high (> + // 500kbit/s) bitrates, where interrupt overhead becomes a slowdown. + if (_tx_buffer_head == _tx_buffer_tail && bit_is_set(*_ucsra, UDRE0)) { + *_udr = c; + sbi(*_ucsra, TXC0); + return 1; + } + int i = (_tx_buffer_head + 1) % SERIAL_BUFFER_SIZE; // If the output buffer is full, there's nothing for it other than to // wait for the interrupt handler to empty it a bit - // ???: return 0 here instead? - while (i == _tx_buffer->tail) - ; - - _tx_buffer->buffer[_tx_buffer->head] = c; - _tx_buffer->head = i; + while (i == _tx_buffer_tail) { + if (bit_is_clear(SREG, SREG_I)) { + // Interrupts are disabled, so we'll have to poll the data + // register empty flag ourselves. If it is set, pretend an + // interrupt has happened and call the handler to free up + // space for us. + if(bit_is_set(*_ucsra, UDRE0)) + _tx_udr_empty_irq(); + } else { + // nop, the interrupt handler will free up space for us + } + } + + _tx_buffer[_tx_buffer_head] = c; + _tx_buffer_head = i; - sbi(*_ucsrb, _udrie); - // clear the TXC bit -- "can be cleared by writing a one to its bit location" - transmitting = true; - sbi(*_ucsra, TXC0); + sbi(*_ucsrb, UDRIE0); + _written = true; return 1; } -HardwareSerial::operator bool() { - return true; -} - -// Preinstantiate Objects ////////////////////////////////////////////////////// - -#if defined(UBRRH) && defined(UBRRL) - HardwareSerial Serial(&rx_buffer, &tx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UCSRC, &UDR, RXEN, TXEN, RXCIE, UDRIE, U2X); -#elif defined(UBRR0H) && defined(UBRR0L) - HardwareSerial Serial(&rx_buffer, &tx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UCSR0C, &UDR0, RXEN0, TXEN0, RXCIE0, UDRIE0, U2X0); -#elif defined(USBCON) - // do nothing - Serial object and buffers are initialized in CDC code -#else - #error no serial port defined (port 0) -#endif - -#if defined(UBRR1H) - HardwareSerial Serial1(&rx_buffer1, &tx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UCSR1C, &UDR1, RXEN1, TXEN1, RXCIE1, UDRIE1, U2X1); -#endif -#if defined(UBRR2H) - HardwareSerial Serial2(&rx_buffer2, &tx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UCSR2C, &UDR2, RXEN2, TXEN2, RXCIE2, UDRIE2, U2X2); -#endif -#if defined(UBRR3H) - HardwareSerial Serial3(&rx_buffer3, &tx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UCSR3C, &UDR3, RXEN3, TXEN3, RXCIE3, UDRIE3, U2X3); -#endif #endif // whole file - |