diff --git a/cpu/avr/dev/arduino/HardwareSerial.cpp b/cpu/avr/dev/arduino/HardwareSerial.cpp new file mode 100644 index 000000000..5cd89e5e6 --- /dev/null +++ b/cpu/avr/dev/arduino/HardwareSerial.cpp @@ -0,0 +1,250 @@ +/* + 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 + Modified 28 September 2010 by Mark Sproul + Modified 14 August 2012 by Alarus + Modified 3 December 2013 by Matthijs Kooijman +*/ + +#include +#include +#include +#include +#include "Arduino.h" + +#include "HardwareSerial.h" +#include "HardwareSerial_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(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)); + bool Serial0_available() __attribute__((weak)); +#endif + +#if defined(HAVE_HWSERIAL1) + void serialEvent1() __attribute__((weak)); + bool Serial1_available() __attribute__((weak)); +#endif + +#if defined(HAVE_HWSERIAL2) + void serialEvent2() __attribute__((weak)); + bool Serial2_available() __attribute__((weak)); +#endif + +#if defined(HAVE_HWSERIAL3) + void serialEvent3() __attribute__((weak)); + bool Serial3_available() __attribute__((weak)); +#endif + +void serialEventRun(void) +{ +#if defined(HAVE_HWSERIAL0) + if (Serial0_available && serialEvent && Serial0_available()) serialEvent(); +#endif +#if defined(HAVE_HWSERIAL1) + if (Serial1_available && serialEvent1 && Serial1_available()) serialEvent1(); +#endif +#if defined(HAVE_HWSERIAL2) + if (Serial2_available && serialEvent2 && Serial2_available()) serialEvent2(); +#endif +#if defined(HAVE_HWSERIAL3) + if (Serial3_available && serialEvent3 && Serial3_available()) serialEvent3(); +#endif +} + +// Actual interrupt handlers ////////////////////////////////////////////////////////////// + +void HardwareSerial::_tx_udr_empty_irq(void) +{ + // 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_TX_BUFFER_SIZE; + + *_udr = c; + + // 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); + + if (_tx_buffer_head == _tx_buffer_tail) { + // Buffer empty, so disable interrupts + cbi(*_ucsrb, UDRIE0); + } +} + +// Public Methods ////////////////////////////////////////////////////////////// + +void HardwareSerial::begin(unsigned long baud, byte config) +{ + // Try u2x mode first + uint16_t baud_setting = (F_CPU / 4 / baud - 1) / 2; + *_ucsra = 1 << U2X0; + + // 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; + } + + // assign the baud_setting, a.k.a. ubrr (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, RXEN0); + sbi(*_ucsrb, TXEN0); + sbi(*_ucsrb, RXCIE0); + cbi(*_ucsrb, UDRIE0); +} + +void HardwareSerial::end() +{ + // wait for transmission of outgoing data + flush(); + + cbi(*_ucsrb, RXEN0); + cbi(*_ucsrb, TXEN0); + cbi(*_ucsrb, RXCIE0); + cbi(*_ucsrb, UDRIE0); + + // clear any received data + _rx_buffer_head = _rx_buffer_tail; +} + +int HardwareSerial::available(void) +{ + return ((unsigned int)(SERIAL_RX_BUFFER_SIZE + _rx_buffer_head - _rx_buffer_tail)) % SERIAL_RX_BUFFER_SIZE; +} + +int HardwareSerial::peek(void) +{ + if (_rx_buffer_head == _rx_buffer_tail) { + return -1; + } else { + 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) { + return -1; + } else { + unsigned char c = _rx_buffer[_rx_buffer_tail]; + _rx_buffer_tail = (rx_buffer_index_t)(_rx_buffer_tail + 1) % SERIAL_RX_BUFFER_SIZE; + return c; + } +} + +int HardwareSerial::availableForWrite(void) +{ +#if (SERIAL_TX_BUFFER_SIZE>256) + uint8_t oldSREG = SREG; + cli(); +#endif + tx_buffer_index_t head = _tx_buffer_head; + tx_buffer_index_t tail = _tx_buffer_tail; +#if (SERIAL_TX_BUFFER_SIZE>256) + SREG = oldSREG; +#endif + if (head >= tail) return SERIAL_TX_BUFFER_SIZE - 1 - head + tail; + return tail - head - 1; +} + +void HardwareSerial::flush() +{ + // 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) +{ + _written = true; + // 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; + } + tx_buffer_index_t i = (_tx_buffer_head + 1) % SERIAL_TX_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 + 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, UDRIE0); + + return 1; +} + +#endif // whole file diff --git a/cpu/avr/dev/arduino/HardwareSerial.h b/cpu/avr/dev/arduino/HardwareSerial.h new file mode 100644 index 000000000..8a5bf95e6 --- /dev/null +++ b/cpu/avr/dev/arduino/HardwareSerial.h @@ -0,0 +1,161 @@ +/* + HardwareSerial.h - 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 28 September 2010 by Mark Sproul + Modified 14 August 2012 by Alarus + Modified 3 December 2013 by Matthijs Kooijman +*/ + +#ifndef HardwareSerial_h +#define HardwareSerial_h + +#include + +#include "Stream.h" + +// 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. +// NOTE: a "power of 2" buffer size is reccomended to dramatically +// optimize all the modulo operations for ring buffers. +// WARNING: When buffer sizes are increased to > 256, the buffer index +// variables are automatically increased in size, but the extra +// atomicity guards needed for that are not implemented. This will +// often work, but occasionally a race condition can occur that makes +// Serial behave erratically. See https://github.com/arduino/Arduino/issues/2405 +#if !defined(SERIAL_TX_BUFFER_SIZE) +#if ((RAMEND - RAMSTART) < 1023) +#define SERIAL_TX_BUFFER_SIZE 16 +#else +#define SERIAL_TX_BUFFER_SIZE 64 +#endif +#endif +#if !defined(SERIAL_RX_BUFFER_SIZE) +#if ((RAMEND - RAMSTART) < 1023) +#define SERIAL_RX_BUFFER_SIZE 16 +#else +#define SERIAL_RX_BUFFER_SIZE 64 +#endif +#endif +#if (SERIAL_TX_BUFFER_SIZE>256) +typedef uint16_t tx_buffer_index_t; +#else +typedef uint8_t tx_buffer_index_t; +#endif +#if (SERIAL_RX_BUFFER_SIZE>256) +typedef uint16_t rx_buffer_index_t; +#else +typedef uint8_t rx_buffer_index_t; +#endif + +// Define config for Serial.begin(baud, config); +#define SERIAL_5N1 0x00 +#define SERIAL_6N1 0x02 +#define SERIAL_7N1 0x04 +#define SERIAL_8N1 0x06 +#define SERIAL_5N2 0x08 +#define SERIAL_6N2 0x0A +#define SERIAL_7N2 0x0C +#define SERIAL_8N2 0x0E +#define SERIAL_5E1 0x20 +#define SERIAL_6E1 0x22 +#define SERIAL_7E1 0x24 +#define SERIAL_8E1 0x26 +#define SERIAL_5E2 0x28 +#define SERIAL_6E2 0x2A +#define SERIAL_7E2 0x2C +#define SERIAL_8E2 0x2E +#define SERIAL_5O1 0x30 +#define SERIAL_6O1 0x32 +#define SERIAL_7O1 0x34 +#define SERIAL_8O1 0x36 +#define SERIAL_5O2 0x38 +#define SERIAL_6O2 0x3A +#define SERIAL_7O2 0x3C +#define SERIAL_8O2 0x3E + +class HardwareSerial : public Stream +{ + protected: + volatile uint8_t * const _ubrrh; + volatile uint8_t * const _ubrrl; + volatile uint8_t * const _ucsra; + volatile uint8_t * const _ucsrb; + volatile uint8_t * const _ucsrc; + volatile uint8_t * const _udr; + // Has any byte been written to the UART since begin() + bool _written; + + volatile rx_buffer_index_t _rx_buffer_head; + volatile rx_buffer_index_t _rx_buffer_tail; + volatile tx_buffer_index_t _tx_buffer_head; + volatile tx_buffer_index_t _tx_buffer_tail; + + // Don't put any members after these buffers, since only the first + // 32 bytes of this struct can be accessed quickly using the ldd + // instruction. + unsigned char _rx_buffer[SERIAL_RX_BUFFER_SIZE]; + unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE]; + + public: + inline HardwareSerial( + volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, + volatile uint8_t *ucsra, volatile uint8_t *ucsrb, + volatile uint8_t *ucsrc, volatile uint8_t *udr); + void begin(unsigned long baud) { begin(baud, SERIAL_8N1); } + void begin(unsigned long, uint8_t); + void end(); + virtual int available(void); + virtual int peek(void); + virtual int read(void); + int availableForWrite(void); + virtual void flush(void); + virtual size_t write(uint8_t); + inline size_t write(unsigned long n) { return write((uint8_t)n); } + inline size_t write(long n) { return write((uint8_t)n); } + inline size_t write(unsigned int n) { return write((uint8_t)n); } + inline size_t write(int n) { return write((uint8_t)n); } + using Print::write; // pull in write(str) and write(buf, size) from Print + operator bool() { return true; } + + // Interrupt handlers - Not intended to be called externally + inline void _rx_complete_irq(void); + void _tx_udr_empty_irq(void); +}; + +#if defined(UBRRH) || defined(UBRR0H) + extern HardwareSerial Serial; + #define HAVE_HWSERIAL0 +#endif +#if defined(UBRR1H) + extern HardwareSerial Serial1; + #define HAVE_HWSERIAL1 +#endif +#if defined(UBRR2H) + extern HardwareSerial Serial2; + #define HAVE_HWSERIAL2 +#endif +#if defined(UBRR3H) + extern HardwareSerial Serial3; + #define HAVE_HWSERIAL3 +#endif + +extern void serialEventRun(void) __attribute__((weak)); + +#endif diff --git a/cpu/avr/dev/arduino/HardwareSerial0.cpp b/cpu/avr/dev/arduino/HardwareSerial0.cpp new file mode 100644 index 000000000..1146eebab --- /dev/null +++ b/cpu/avr/dev/arduino/HardwareSerial0.cpp @@ -0,0 +1,79 @@ +/* + HardwareSerial0.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 + Modified 28 September 2010 by Mark Sproul + Modified 14 August 2012 by Alarus + Modified 3 December 2013 by Matthijs Kooijman +*/ + +#include "Arduino.h" +#include "HardwareSerial.h" +#include "HardwareSerial_private.h" + +// Each HardwareSerial is defined in its own file, sine the linker pulls +// in the entire file when any element inside is used. --gc-sections can +// additionally cause unused symbols to be dropped, but ISRs have the +// "used" attribute so are never dropped and they keep the +// HardwareSerial instance in as well. Putting each instance in its own +// file prevents the linker from pulling in any unused instances in the +// first place. + +#if defined(HAVE_HWSERIAL0) + +#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 +#else + #error "Don't know what the Data Received vector is called for Serial" +#endif + { + Serial._rx_complete_irq(); + } + +#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) +#else + #error "Don't know what the Data Register Empty vector is called for Serial" +#endif +{ + Serial._tx_udr_empty_irq(); +} + +#if defined(UBRRH) && defined(UBRRL) + HardwareSerial Serial(&UBRRH, &UBRRL, &UCSRA, &UCSRB, &UCSRC, &UDR); +#else + HardwareSerial Serial(&UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UCSR0C, &UDR0); +#endif + +// Function that can be weakly referenced by serialEventRun to prevent +// pulling in this file if it's not otherwise used. +bool Serial0_available() { + return Serial.available(); +} + +#endif // HAVE_HWSERIAL0 diff --git a/cpu/avr/dev/arduino/HardwareSerial1.cpp b/cpu/avr/dev/arduino/HardwareSerial1.cpp new file mode 100644 index 000000000..19625e235 --- /dev/null +++ b/cpu/avr/dev/arduino/HardwareSerial1.cpp @@ -0,0 +1,69 @@ +/* + HardwareSerial1.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 + Modified 28 September 2010 by Mark Sproul + Modified 14 August 2012 by Alarus + Modified 3 December 2013 by Matthijs Kooijman +*/ + +#include "Arduino.h" +#include "HardwareSerial.h" +#include "HardwareSerial_private.h" + +// Each HardwareSerial is defined in its own file, sine the linker pulls +// in the entire file when any element inside is used. --gc-sections can +// additionally cause unused symbols to be dropped, but ISRs have the +// "used" attribute so are never dropped and they keep the +// HardwareSerial instance in as well. Putting each instance in its own +// file prevents the linker from pulling in any unused instances in the +// first place. + +#if defined(HAVE_HWSERIAL1) + +#if defined(UART1_RX_vect) +ISR(UART1_RX_vect) +#elif defined(USART1_RX_vect) +ISR(USART1_RX_vect) +#else +#error "Don't know what the Data Register Empty vector is called for Serial1" +#endif +{ + Serial1._rx_complete_irq(); +} + +#if defined(UART1_UDRE_vect) +ISR(UART1_UDRE_vect) +#elif defined(USART1_UDRE_vect) +ISR(USART1_UDRE_vect) +#else +#error "Don't know what the Data Register Empty vector is called for Serial1" +#endif +{ + Serial1._tx_udr_empty_irq(); +} + +HardwareSerial Serial1(&UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UCSR1C, &UDR1); + +// Function that can be weakly referenced by serialEventRun to prevent +// pulling in this file if it's not otherwise used. +bool Serial1_available() { + return Serial1.available(); +} + +#endif // HAVE_HWSERIAL1 diff --git a/cpu/avr/dev/arduino/HardwareSerial_private.h b/cpu/avr/dev/arduino/HardwareSerial_private.h new file mode 100644 index 000000000..761a5e559 --- /dev/null +++ b/cpu/avr/dev/arduino/HardwareSerial_private.h @@ -0,0 +1,123 @@ +/* + HardwareSerial_private.h - 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 + Modified 28 September 2010 by Mark Sproul + Modified 14 August 2012 by Alarus +*/ + +#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(HAVE_HWSERIAL0) || defined(HAVE_HWSERIAL1) || defined(HAVE_HWSERIAL2) || defined(HAVE_HWSERIAL3) + +// Ensure that the various bit positions we use are available with a 0 +// postfix, so we can always use the values for UART0 for all UARTs. The +// alternative, passing the various values for each UART to the +// HardwareSerial constructor also works, but makes the code bigger and +// slower. +#if !defined(TXC0) +#if defined(TXC) +// Some chips like ATmega8 don't have UPE, only PE. The other bits are +// named as expected. +#if !defined(UPE) && defined(PE) +#define UPE PE +#endif +// On ATmega8, the uart and its bits are not numbered, so there is no TXC0 etc. +#define TXC0 TXC +#define RXEN0 RXEN +#define TXEN0 TXEN +#define RXCIE0 RXCIE +#define UDRIE0 UDRIE +#define U2X0 U2X +#define UPE0 UPE +#define UDRE0 UDRE +#elif defined(TXC1) +// Some devices have uart1 but no uart0 +#define TXC0 TXC1 +#define RXEN0 RXEN1 +#define TXEN0 TXEN1 +#define RXCIE0 RXCIE1 +#define UDRIE0 UDRIE1 +#define U2X0 U2X1 +#define UPE0 UPE1 +#define UDRE0 UDRE1 +#else +#error No UART found in HardwareSerial.cpp +#endif +#endif // !defined TXC0 + +// Check at compiletime that it is really ok to use the bit positions of +// UART0 for the other UARTs as well, in case these values ever get +// changed for future hardware. +#if defined(TXC1) && (TXC1 != TXC0 || RXEN1 != RXEN0 || RXCIE1 != RXCIE0 || \ + UDRIE1 != UDRIE0 || U2X1 != U2X0 || UPE1 != UPE0 || \ + UDRE1 != UDRE0) +#error "Not all bit positions for UART1 are the same as for UART0" +#endif +#if defined(TXC2) && (TXC2 != TXC0 || RXEN2 != RXEN0 || RXCIE2 != RXCIE0 || \ + UDRIE2 != UDRIE0 || U2X2 != U2X0 || UPE2 != UPE0 || \ + UDRE2 != UDRE0) +#error "Not all bit positions for UART2 are the same as for UART0" +#endif +#if defined(TXC3) && (TXC3 != TXC0 || RXEN3 != RXEN0 || RXCIE3 != RXCIE0 || \ + UDRIE3 != UDRIE0 || U3X3 != U3X0 || UPE3 != UPE0 || \ + UDRE3 != UDRE0) +#error "Not all bit positions for UART3 are the same as for UART0" +#endif + +// Constructors //////////////////////////////////////////////////////////////// + +HardwareSerial::HardwareSerial( + volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, + volatile uint8_t *ucsra, volatile uint8_t *ucsrb, + volatile uint8_t *ucsrc, volatile uint8_t *udr) : + _ubrrh(ubrrh), _ubrrl(ubrrl), + _ucsra(ucsra), _ucsrb(ucsrb), _ucsrc(ucsrc), + _udr(udr), + _rx_buffer_head(0), _rx_buffer_tail(0), + _tx_buffer_head(0), _tx_buffer_tail(0) +{ +} + +// Actual interrupt handlers ////////////////////////////////////////////////////////////// + +void HardwareSerial::_rx_complete_irq(void) +{ + if (bit_is_clear(*_ucsra, UPE0)) { + // No Parity error, read byte and store it in the buffer if there is + // room + unsigned char c = *_udr; + rx_buffer_index_t i = (unsigned int)(_rx_buffer_head + 1) % SERIAL_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[_rx_buffer_head] = c; + _rx_buffer_head = i; + } + } else { + // Parity error, read byte but discard it + *_udr; + }; +} + +#endif // whole file