2 HardwareSerial.h - Hardware serial library for Wiring
3 Copyright (c) 2006 Nicholas Zambetti. All right reserved.
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 Modified 28 September 2010 by Mark Sproul
20 Modified 14 August 2012 by Alarus
21 Modified 3 December 2013 by Matthijs Kooijman
24 #ifndef HardwareSerial_h
25 #define HardwareSerial_h
31 // Define constants and variables for buffering incoming serial data. We're
32 // using a ring buffer (I think), in which head is the index of the location
33 // to which to write the next incoming character and tail is the index of the
34 // location from which to read.
35 // NOTE: a "power of 2" buffer size is reccomended to dramatically
36 // optimize all the modulo operations for ring buffers.
37 // WARNING: When buffer sizes are increased to > 256, the buffer index
38 // variables are automatically increased in size, but the extra
39 // atomicity guards needed for that are not implemented. This will
40 // often work, but occasionally a race condition can occur that makes
41 // Serial behave erratically. See https://github.com/arduino/Arduino/issues/2405
42 #if !defined(SERIAL_TX_BUFFER_SIZE)
43 #if ((RAMEND - RAMSTART) < 1023)
44 #define SERIAL_TX_BUFFER_SIZE 16
46 #define SERIAL_TX_BUFFER_SIZE 64
49 #if !defined(SERIAL_RX_BUFFER_SIZE)
50 #if ((RAMEND - RAMSTART) < 1023)
51 #define SERIAL_RX_BUFFER_SIZE 16
53 #define SERIAL_RX_BUFFER_SIZE 64
56 #if (SERIAL_TX_BUFFER_SIZE>256)
57 typedef uint16_t tx_buffer_index_t;
59 typedef uint8_t tx_buffer_index_t;
61 #if (SERIAL_RX_BUFFER_SIZE>256)
62 typedef uint16_t rx_buffer_index_t;
64 typedef uint8_t rx_buffer_index_t;
67 // Define config for Serial.begin(baud, config);
68 #define SERIAL_5N1 0x00
69 #define SERIAL_6N1 0x02
70 #define SERIAL_7N1 0x04
71 #define SERIAL_8N1 0x06
72 #define SERIAL_5N2 0x08
73 #define SERIAL_6N2 0x0A
74 #define SERIAL_7N2 0x0C
75 #define SERIAL_8N2 0x0E
76 #define SERIAL_5E1 0x20
77 #define SERIAL_6E1 0x22
78 #define SERIAL_7E1 0x24
79 #define SERIAL_8E1 0x26
80 #define SERIAL_5E2 0x28
81 #define SERIAL_6E2 0x2A
82 #define SERIAL_7E2 0x2C
83 #define SERIAL_8E2 0x2E
84 #define SERIAL_5O1 0x30
85 #define SERIAL_6O1 0x32
86 #define SERIAL_7O1 0x34
87 #define SERIAL_8O1 0x36
88 #define SERIAL_5O2 0x38
89 #define SERIAL_6O2 0x3A
90 #define SERIAL_7O2 0x3C
91 #define SERIAL_8O2 0x3E
93 class HardwareSerial : public Stream
96 volatile uint8_t * const _ubrrh;
97 volatile uint8_t * const _ubrrl;
98 volatile uint8_t * const _ucsra;
99 volatile uint8_t * const _ucsrb;
100 volatile uint8_t * const _ucsrc;
101 volatile uint8_t * const _udr;
102 // Has any byte been written to the UART since begin()
105 volatile rx_buffer_index_t _rx_buffer_head;
106 volatile rx_buffer_index_t _rx_buffer_tail;
107 volatile tx_buffer_index_t _tx_buffer_head;
108 volatile tx_buffer_index_t _tx_buffer_tail;
110 // Don't put any members after these buffers, since only the first
111 // 32 bytes of this struct can be accessed quickly using the ldd
113 unsigned char _rx_buffer[SERIAL_RX_BUFFER_SIZE];
114 unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE];
117 inline HardwareSerial(
118 volatile uint8_t *ubrrh, volatile uint8_t *ubrrl,
119 volatile uint8_t *ucsra, volatile uint8_t *ucsrb,
120 volatile uint8_t *ucsrc, volatile uint8_t *udr);
121 void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }
122 void begin(unsigned long, uint8_t);
124 virtual int available(void);
125 virtual int peek(void);
126 virtual int read(void);
127 virtual int availableForWrite(void);
128 virtual void flush(void);
129 virtual size_t write(uint8_t);
130 inline size_t write(unsigned long n) { return write((uint8_t)n); }
131 inline size_t write(long n) { return write((uint8_t)n); }
132 inline size_t write(unsigned int n) { return write((uint8_t)n); }
133 inline size_t write(int n) { return write((uint8_t)n); }
134 using Print::write; // pull in write(str) and write(buf, size) from Print
135 operator bool() { return true; }
137 // Interrupt handlers - Not intended to be called externally
138 inline void _rx_complete_irq(void);
139 void _tx_udr_empty_irq(void);
142 #if defined(UBRRH) || defined(UBRR0H)
143 extern HardwareSerial Serial;
144 #define HAVE_HWSERIAL0
147 extern HardwareSerial Serial1;
148 #define HAVE_HWSERIAL1
151 extern HardwareSerial Serial2;
152 #define HAVE_HWSERIAL2
155 extern HardwareSerial Serial3;
156 #define HAVE_HWSERIAL3
159 extern void serialEventRun(void) __attribute__((weak));