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

1 files changed, 4 insertions, 3 deletions

diff --git a/cores/arduino/HardwareSerial.h b/cores/arduino/HardwareSerial.h
index 3efa775..d229373 100644
--- a/cores/arduino/HardwareSerial.h
+++ b/cores/arduino/HardwareSerial.h
@@ -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);