Sam Grove / BufferedSerial

Inherit from Serial and use software buffers for TX and RX. This allows the UART peripherals to operate in a IRQ driven mode. Overrides most (but not all) stdio functions as Serial did

Dependencies:   Buffer

Dependents:   buffered_serial_test BLE_Police_HRM evena_BLE_Police_HRM df-2014-workshop-rfid-case-generator-k64f ... more

Example

 #include "mbed.h"
 #include "BufferedSerial.h"

 BufferedSerial pc(USBTX, USBRX);

 int main()
 {
     pc.baud(115200);
   
     while(1)
     {
         Timer s;
       
         s.start();
         pc.printf("Hello World - buff\n");
         int buffered_time = s.read_us();
         wait(0.1f); // give time for the buffer to empty
       
         s.reset();
         printf("Hello World - poll\n");
         int polled_time = s.read_us();
         s.stop();
         wait(0.1f); // give time for the buffer to empty
       
         pc.printf("printf buffered took %d us\n", buffered_time);
         pc.printf("printf polled took %d us\n", polled_time);
         wait(0.5f);
     }
 }

Diff: BufferedSerial.cpp

Revision:
1:57a11fb5d529
Parent:
0:a977d0a3d81e
Child:
2:7e8a450a9101
--- a/BufferedSerial.cpp	Thu May 23 19:31:30 2013 +0000
+++ b/BufferedSerial.cpp	Thu May 23 23:47:04 2013 +0000
@@ -59,7 +59,7 @@
 int BufferedSerial::putc(int c)
 {
     _txbuf = (char)c;
-    BufferedSerial::txIrq();    // prime the txirq to stoke transmit
+    BufferedSerial::prime();
     
     return c;
 }
@@ -72,7 +72,7 @@
     {
         _txbuf = *(s++);
     }
-    BufferedSerial::txIrq();    // prime the txirq to stoke transmit
+    BufferedSerial::prime();
     
     return s - size;
 }
@@ -118,5 +118,14 @@
     return;
 }
 
+void BufferedSerial::prime(void)
+{
+    __disable_irq();    // make sure not to cause contention in the irq 
+    BufferedSerial::txIrq();    // prime the txirq to stoke transmit
+    __enable_irq();
+    
+    return;
+}
 
 
+