Revision 0:707b9f3904dd, committed 2012-12-10

Comitter:

tylerjw

Date:

Mon Dec 10 23:42:38 2012 +0000

Child:

1:eabb26ce183b

Commit message:

initial commit - working with UART1 (p13,p14)

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/buffered_serial.cpp	Mon Dec 10 23:42:38 2012 +0000
@@ -0,0 +1,108 @@
+#include "buffered_serial.h"
+
+BufferedSerial::BufferedSerial(PinName tx, PinName rx) : Serial(tx,rx), led1(LED1), led2(LED2), rx_sem(0), tx_sem(0)
+{
+    tx_in=0;
+    tx_out=0;
+    rx_in=0;
+    rx_out=0;
+
+    device_irqn = UART1_IRQn;
+
+    // attach the interrupts
+    Serial::attach(this, &BufferedSerial::Rx_interrupt, Serial::RxIrq);
+    Serial::attach(this, &BufferedSerial::Tx_interrupt, Serial::TxIrq);
+}
+
+// Copy tx line buffer to large tx buffer for tx interrupt routine
+void BufferedSerial::send_line(char *c)
+{
+    int i;
+    char temp_char;
+    bool empty;
+    i = 0;
+    strncpy(tx_line,c,LINE_SIZE);
+    // Start Critical Section - don't interrupt while changing global buffer variables
+    NVIC_DisableIRQ(device_irqn);
+    empty = (tx_in == tx_out);
+    while ((i==0) || (tx_line[i-1] != '\n')) {
+        // Wait if buffer full
+        if (IS_TX_FULL) {
+            // End Critical Section - need to let interrupt routine empty buffer by sending
+            NVIC_EnableIRQ(device_irqn);
+            //while (IS_TX_FULL) ; // buffer is full
+            tx_sem.wait();
+            // Start Critical Section - don't interrupt while changing global buffer variables
+            NVIC_DisableIRQ(device_irqn);
+        }
+        tx_buffer[tx_in] = tx_line[i];
+        i++;
+        tx_in = NEXT(tx_in);
+    }
+    if (Serial::writeable() && (empty)) {
+        temp_char = tx_buffer[tx_out];
+        tx_out = NEXT(tx_out);
+        // Send first character to start tx interrupts, if stopped
+        LPC_UART1->THR = temp_char;
+    }
+    // End Critical Section
+    NVIC_EnableIRQ(device_irqn);
+}
+
+// Read a line from the large rx buffer from rx interrupt routine
+void BufferedSerial::read_line(char *c)
+{
+    int i;
+    i = 0;
+    // Start Critical Section - don't interrupt while changing global buffer variables
+    NVIC_DisableIRQ(device_irqn);
+    // Loop reading rx buffer characters until end of line character
+    while ((i==0) || (rx_line[i-1] != '\r')) {
+        // Wait if buffer empty
+        if (IS_RX_EMPTY) { // buffer empty
+            // End Critical Section - need to allow rx interrupt to get new characters for buffer
+            NVIC_EnableIRQ(device_irqn);
+            //while (rx_in == rx_out) ; // buffer empty
+            rx_sem.wait();
+            // Start Critical Section - don't interrupt while changing global buffer variables
+            NVIC_DisableIRQ(device_irqn);
+        } else {
+            rx_sem.wait();
+        }
+        rx_line[i] = rx_buffer[rx_out];
+        i++;
+        rx_out = NEXT(rx_out);
+
+    }
+    rx_line[i-1] = 0;
+    // End Critical Section
+    NVIC_EnableIRQ(device_irqn);
+    strncpy(c,rx_line,LINE_SIZE);
+}
+
+// Interupt Routine to read in data from serial port
+void BufferedSerial::Rx_interrupt()
+{
+    uint32_t IRR1 = LPC_UART1->IIR;
+    led1=1;
+    while (readable() && !(IS_RX_FULL)) {
+        rx_buffer[rx_in] = LPC_UART1->RBR;
+        rx_in = NEXT(rx_in);
+        rx_sem.release();
+    }
+    led1=0;
+}
+
+// Interupt Routine to write out data to serial port
+void BufferedSerial::Tx_interrupt()
+{
+    uint32_t IRR = LPC_UART1->IIR;
+    led2=1;
+    while ((writeable()) && (tx_in != tx_out)) { // while serial is writeable and there are still characters in the buffer
+        LPC_UART1->THR = tx_buffer[tx_out]; // send the character
+        tx_out = NEXT(tx_out);
+    }
+    if(!IS_TX_FULL) // if not full
+        tx_sem.release();
+    led2=0;
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/buffered_serial.h	Mon Dec 10 23:42:38 2012 +0000
@@ -0,0 +1,54 @@
+/*
+    Buffered serial 1 - Setup to work with UART1 (p13,p14)
+*/
+
+#ifndef BUFFERED_SERIAL_H
+#define BUFFERED_SERIAL_H
+
+#define BUFFER_SIZE     255
+#define LINE_SIZE       80
+#define NEXT(x)         ((x+1)&BUFFER_SIZE)
+#define IS_TX_FULL      (((tx_in + 1) & BUFFER_SIZE) == tx_out)
+#define IS_RX_FULL      (((rx_in + 1) & BUFFER_SIZE) == rx_out)
+#define IS_RX_EMPTY     (rx_in == rx_out)
+
+#include "mbed.h"
+#include "rtos.h"
+
+class BufferedSerial : public Serial
+{
+public:
+    BufferedSerial(PinName tx, PinName rx);
+
+    void send_line(char*);
+    void read_line(char*);
+
+private:
+    void Tx_interrupt();
+    void Rx_interrupt();
+
+// for disabling the irq
+    IRQn device_irqn;
+    
+// Circular buffers for serial TX and RX data - used by interrupt routines
+// might need to increase buffer size for high baud rates
+    char tx_buffer[BUFFER_SIZE];
+    char rx_buffer[BUFFER_SIZE];
+// Circular buffer pointers
+// volatile makes read-modify-write atomic
+    volatile int tx_in;
+    volatile int tx_out;
+    volatile int rx_in;
+    volatile int rx_out;
+// Line buffers for sprintf and sscanf
+    char tx_line[LINE_SIZE];
+    char rx_line[LINE_SIZE];
+
+    DigitalOut led1;
+    DigitalOut led2;
+    
+    Semaphore rx_sem;
+    Semaphore tx_sem;
+};
+
+#endif
\ No newline at end of file