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);
     }
 }

Files at this revision

API Documentation at this revision

Revision 1:57a11fb5d529, committed 2013-05-23

Comitter:
sam_grove
Date:
Thu May 23 23:47:04 2013 +0000
Parent:
0:a977d0a3d81e
Child:
2:7e8a450a9101
Commit message:
Added prime (private member).Only want to pull from the buffer and write in one spot. prime stops irq's and call the member txIrq to put the oldest buffered byte in the transmitter. IRQ will pull the rest out once enabled again.

Changed in this revision

BufferedSerial.cpp Show annotated file Show diff for this revision Revisions of this file
BufferedSerial.h Show annotated file Show diff for this revision Revisions of this file 
--- 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;
+}
 
 
+

--- a/BufferedSerial.h	Thu May 23 19:31:30 2013 +0000
+++ b/BufferedSerial.h	Thu May 23 23:47:04 2013 +0000
@@ -78,6 +78,7 @@
  
     void rxIrq(void);
     void txIrq(void);
+    void prime(void);
     
 public:
     /** Create a BufferedSerial port, connected to the specified transmit and receive pins