noisymime
/
Arduino
mirror of https://github.com/noisymime/Arduino.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Implemented serial transmit buffering. 

Now Serial.write() places characters in the transmit buffer, and the data register empty interrupt reads and transmit them.  Based loosely on the implementation here: ftp://wookey.org.uk/arduino.

http://code.google.com/p/arduino/issues/detail?id=262
This commit is contained in:
David A. Mellis 2011-03-05 14:17:26 -05:00
parent 19597b1d0b
commit 7f0cc2111c
2 changed files with 138 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

160
hardware/arduino/cores/arduino/HardwareSerial.cpp
View File

@ -34,46 +34,50 @@
#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.
// 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 RX_BUFFER_SIZE 32
#define SERIAL_BUFFER_SIZE 16
#else
#define RX_BUFFER_SIZE 128
#define SERIAL_BUFFER_SIZE 64
#endif
struct ring_buffer
{
unsigned char buffer[RX_BUFFER_SIZE];
int head;
int tail;
unsigned char buffer[SERIAL_BUFFER_SIZE];
volatile int head;
volatile int tail;
};
#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 *rx_buffer)
inline void store_char(unsigned char c, ring_buffer *buffer)
{
int i = (unsigned int)(rx_buffer->head + 1) % RX_BUFFER_SIZE;
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 != rx_buffer->tail) {
rx_buffer->buffer[rx_buffer->head] = c;
rx_buffer->head = i;
if (i != buffer->tail) {
buffer->buffer[buffer->head] = c;
buffer->head = i;
}
}
@ -167,16 +171,105 @@ inline void store_char(unsigned char c, ring_buffer *rx_buffer)
#endif
#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
{
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
#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
#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
#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;
}
}
#endif
// Constructors ////////////////////////////////////////////////////////////////
HardwareSerial::HardwareSerial(ring_buffer *rx_buffer,
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 *udr,
uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre, uint8_t u2x)
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;
@ -185,7 +278,7 @@ HardwareSerial::HardwareSerial(ring_buffer *rx_buffer,
_rxen = rxen;
_txen = txen;
_rxcie = rxcie;
_udre = udre;
_udrie = udrie;
_u2x = u2x;
}
@ -220,18 +313,21 @@ void HardwareSerial::begin(long baud)
sbi(*_ucsrb, _rxen);
sbi(*_ucsrb, _txen);
sbi(*_ucsrb, _rxcie);
cbi(*_ucsrb, _udrie); // XXX: what if there's already data in the tx buffer?
}
// XXX: should we empty the rx and tx buffers here?
void HardwareSerial::end()
{
cbi(*_ucsrb, _rxen);
cbi(*_ucsrb, _txen);
cbi(*_ucsrb, _rxcie);
cbi(*_ucsrb, _udrie);
}
int HardwareSerial::available(void)
{
return (unsigned int)(RX_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % RX_BUFFER_SIZE;
return (unsigned int)(SERIAL_BUFFER_SIZE + _rx_buffer->head - _rx_buffer->tail) % SERIAL_BUFFER_SIZE;
}
int HardwareSerial::peek(void)
@ -250,7 +346,7 @@ int HardwareSerial::read(void)
return -1;
} else {
unsigned char c = _rx_buffer->buffer[_rx_buffer->tail];
_rx_buffer->tail = (unsigned int)(_rx_buffer->tail + 1) % RX_BUFFER_SIZE;
_rx_buffer->tail = (unsigned int)(_rx_buffer->tail + 1) % SERIAL_BUFFER_SIZE;
return c;
}
}
@ -271,18 +367,30 @@ void HardwareSerial::flush()
void HardwareSerial::write(uint8_t c)
{
while (!((*_ucsra) & (1 << _udre)))
bool empty = (_tx_buffer->head == _tx_buffer->tail);
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
while (i == _tx_buffer->tail)
;
*_udr = c;
_tx_buffer->buffer[_tx_buffer->head] = c;
_tx_buffer->head = i;
if (empty) {
// The buffer was empty, so enable interrupt on
// USART Data Register empty. The interrupt handler will take it from there
sbi(*_ucsrb, _udrie);
}
}
// Preinstantiate Objects //////////////////////////////////////////////////////
#if defined(UBRRH) && defined(UBRRL)
HardwareSerial Serial(&rx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRE, U2X);
HardwareSerial Serial(&rx_buffer, &tx_buffer, &UBRRH, &UBRRL, &UCSRA, &UCSRB, &UDR, RXEN, TXEN, RXCIE, UDRIE, U2X);
#elif defined(UBRR0H) && defined(UBRR0L)
HardwareSerial Serial(&rx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRE0, U2X0);
HardwareSerial Serial(&rx_buffer, &tx_buffer, &UBRR0H, &UBRR0L, &UCSR0A, &UCSR0B, &UDR0, RXEN0, TXEN0, RXCIE0, UDRIE0, U2X0);
#elif defined(USBCON)
#warning no serial port defined (port 0)
#else
@ -290,13 +398,13 @@ void HardwareSerial::write(uint8_t c)
#endif
#if defined(UBRR1H)
HardwareSerial Serial1(&rx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UDR1, RXEN1, TXEN1, RXCIE1, UDRE1, U2X1);
HardwareSerial Serial1(&rx_buffer1, &tx_buffer1, &UBRR1H, &UBRR1L, &UCSR1A, &UCSR1B, &UDR1, RXEN1, TXEN1, RXCIE1, UDRIE1, U2X1);
#endif
#if defined(UBRR2H)
HardwareSerial Serial2(&rx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UDR2, RXEN2, TXEN2, RXCIE2, UDRE2, U2X2);
HardwareSerial Serial2(&rx_buffer2, &tx_buffer2, &UBRR2H, &UBRR2L, &UCSR2A, &UCSR2B, &UDR2, RXEN2, TXEN2, RXCIE2, UDRIE2, U2X2);
#endif
#if defined(UBRR3H)
HardwareSerial Serial3(&rx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UDR3, RXEN3, TXEN3, RXCIE3, UDRE3, U2X3);
HardwareSerial Serial3(&rx_buffer3, &tx_buffer3, &UBRR3H, &UBRR3L, &UCSR3A, &UCSR3B, &UDR3, RXEN3, TXEN3, RXCIE3, UDRIE3, U2X3);
#endif
#endif // whole file

7
hardware/arduino/cores/arduino/HardwareSerial.h
View File

@ -32,6 +32,7 @@ class HardwareSerial : public Stream
{
private:
ring_buffer *_rx_buffer;
ring_buffer *_tx_buffer;
volatile uint8_t *_ubrrh;
volatile uint8_t *_ubrrl;
volatile uint8_t *_ucsra;
@ -40,14 +41,14 @@ class HardwareSerial : public Stream
uint8_t _rxen;
uint8_t _txen;
uint8_t _rxcie;
uint8_t _udre;
uint8_t _udrie;
uint8_t _u2x;
public:
HardwareSerial(ring_buffer *rx_buffer,
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 *udr,
uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udre, uint8_t u2x);
uint8_t rxen, uint8_t txen, uint8_t rxcie, uint8_t udrie, uint8_t u2x);
void begin(long);
void end();
virtual int available(void);