Richard Sewell
This is the SerialBuffered class, which wraps Serial and adds interrupt-powered buffered reading (so it will catch inbound data even when your app is busy doing something else) and simple read timeouts. There's a tiny demo app in there too.
Diff: SerialBuffered.cpp
- Revision:
- 0:b55ca3bb8017
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/SerialBuffered.cpp Wed Nov 18 21:27:15 2009 +0000
@@ -0,0 +1,108 @@
+
+#include "mbed.h"
+#include "SerialBuffered.h"
+
+extern Serial loggerSerial;
+
+SerialBuffered::SerialBuffered( size_t bufferSize, PinName tx, PinName rx ) : Serial( tx, rx )
+{
+ m_buffSize = 0;
+ m_contentStart = 0;
+ m_contentEnd = 0;
+ m_timeout = 1.0;
+
+
+ attach( this, &SerialBuffered::handleInterrupt );
+
+ m_buff = (uint8_t *) malloc( bufferSize );
+ if( m_buff == NULL )
+ {
+ //loggerSerial.printf("SerialBuffered - failed to alloc buffer size %d\r\n", (int) bufferSize );
+ }
+ else
+ {
+ m_buffSize = bufferSize;
+ }
+}
+
+
+SerialBuffered::~SerialBuffered()
+{
+ if( m_buff )
+ free( m_buff );
+}
+
+void SerialBuffered::setTimeout( float seconds )
+{
+ m_timeout = seconds;
+}
+
+size_t SerialBuffered::readBytes( uint8_t *bytes, size_t requested )
+{
+ int i = 0;
+
+ for( ; i < requested; )
+ {
+ int c = getc();
+ if( c < 0 )
+ break;
+ bytes[i] = c;
+ i++;
+ }
+
+ return i;
+
+}
+
+
+int SerialBuffered::getc()
+{
+ m_timer.reset();
+ m_timer.start();
+ while( m_contentStart == m_contentEnd )
+ {
+
+
+ wait_ms( 1 );
+ if( m_timeout > 0 && m_timer.read() > m_timeout )
+ return EOF;
+ }
+
+ m_timer.stop();
+
+ uint8_t result = m_buff[m_contentStart++];
+ m_contentStart = m_contentStart % m_buffSize;
+
+
+ return result;
+}
+
+
+int SerialBuffered::readable()
+{
+ return m_contentStart != m_contentEnd ;
+}
+
+void SerialBuffered::handleInterrupt()
+{
+
+ while( Serial::readable())
+ {
+ if( m_contentStart == (m_contentEnd +1) % m_buffSize)
+ {
+ loggerSerial.printf("SerialBuffered - buffer overrun, data lost!\r\n" );
+ Serial::getc();
+
+ }
+ else
+ {
+
+ m_buff[ m_contentEnd ++ ] = Serial::getc();
+ m_contentEnd = m_contentEnd % m_buffSize;
+
+
+
+ }
+ }
+}
+