Dr. Pucher
Test
Diff: main.cpp
- Revision:
- 0:023c5cda6102
- Child:
- 2:f026b40fadb1
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Tue Nov 16 15:00:30 2010 +0000
@@ -0,0 +1,181 @@
+
+#include "mbed.h"
+// Serial TX & RX interrupt loopback test using formatted IO - sprintf and sscanf
+// Connect TX to RX (p9 to p10)
+// or can also use USB and type back in the number printed out in a terminal window
+// Sends out ASCII numbers in a loop and reads them back
+// If not the same number LED4 goes on
+// LED1 and LED2 indicate RX and TX interrupt routine activity
+// LED3 changing indicate main loop running
+
+
+Serial device(p9, p10); // tx, rx
+// Can also use USB and type back in the number printed out in a terminal window
+// Serial monitor_device(USBTX, USBRX);
+DigitalOut led1(LED1);
+DigitalOut led2(LED2);
+DigitalOut led3(LED3);
+DigitalOut led4(LED4);
+
+
+void Tx_interrupt();
+void Rx_interrupt();
+void send_line();
+void read_line();
+
+
+// Circular buffers for serial TX and RX data - used by interrupt routines
+const int buffer_size = 255;
+// 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=0;
+volatile int tx_out=0;
+volatile int rx_in=0;
+volatile int rx_out=0;
+// Line buffers for sprintf and sscanf
+char tx_line[80];
+char rx_line[80];
+
+// main test program
+int main() {
+ int i=0;
+ int rx_i=0;
+ device.baud(9600);
+
+// Setup a serial interrupt function to receive data
+ device.attach(&Rx_interrupt, Serial::RxIrq);
+// Setup a serial interrupt function to transmit data
+ device.attach(&Tx_interrupt, Serial::TxIrq);
+
+// Formatted IO test using send and receive serial interrupts
+// with sprintf and sscanf
+ while (1) {
+// Loop to generate different test values - send value in hex, decimal, and octal and then read back
+ for (i=0; i<0xFFFF; i++) {
+ led3=1;
+// Print ASCII number to tx line buffer in hex
+ sprintf(tx_line,"%x\r\n",i);
+// Copy tx line buffer to large tx buffer for tx interrupt routine
+ send_line();
+// Print ASCII number to tx line buffer in decimal
+ sprintf(tx_line,"%d\r\n",i);
+// Copy tx line buffer to large tx buffer for tx interrupt routine
+ send_line();
+// Print ASCII number to tx line buffer in octal
+ sprintf(tx_line,"%o\r\n",i);
+// Copy tx line buffer to large tx buffer for tx interrupt routine
+ send_line();
+ led3=0;
+// Read a line from the large rx buffer from rx interrupt routine
+ read_line();
+// Read ASCII number from rx line buffer
+ sscanf(rx_line,"%x",&rx_i);
+// Check that numbers are the same
+ if (i != rx_i) led4=1;
+// Read a line from the large rx buffer from rx interrupt routine
+ read_line();
+// Read ASCII number from rx line buffer
+ sscanf(rx_line,"%d",&rx_i);
+// Check that numbers are the same
+ if (i != rx_i) led4=1;
+// Read a line from the large rx buffer from rx interrupt routine
+ read_line();
+// Read ASCII number from rx line buffer
+ sscanf(rx_line,"%o",&rx_i);
+// Check that numbers are the same
+ if (i != rx_i) led4=1;
+ }
+ }
+}
+
+// Copy tx line buffer to large tx buffer for tx interrupt routine
+void send_line() {
+ int i;
+ char temp_char;
+ bool empty;
+ i = 0;
+// Start Critical Section - don't interrupt while changing global buffer variables
+ NVIC_DisableIRQ(UART1_IRQn);
+ empty = (tx_in == tx_out);
+ while ((i==0) || (tx_line[i-1] != '\n')) {
+// Wait if buffer full
+ if (((tx_in + 1) % buffer_size) == tx_out) {
+// End Critical Section - need to let interrupt routine empty buffer by sending
+ NVIC_EnableIRQ(UART1_IRQn);
+ while (((tx_in + 1) % buffer_size) == tx_out) {
+ }
+// Start Critical Section - don't interrupt while changing global buffer variables
+ NVIC_DisableIRQ(UART1_IRQn);
+ }
+ tx_buffer[tx_in] = tx_line[i];
+ i++;
+ tx_in = (tx_in + 1) % buffer_size;
+ }
+ if (device.writeable() && (empty)) {
+ temp_char = tx_buffer[tx_out];
+ tx_out = (tx_out + 1) % buffer_size;
+// Send first character to start tx interrupts, if stopped
+ device.putc(temp_char);
+ }
+// End Critical Section
+ NVIC_EnableIRQ(UART1_IRQn);
+ return;
+}
+
+// Read a line from the large rx buffer from rx interrupt routine
+void read_line() {
+ int i;
+ i = 0;
+// Start Critical Section - don't interrupt while changing global buffer variables
+ NVIC_DisableIRQ(UART1_IRQn);
+// Loop reading rx buffer characters until end of line character
+ while ((i==0) || (rx_line[i-1] != '\r')) {
+// Wait if buffer empty
+ if (rx_in == rx_out) {
+// End Critical Section - need to allow rx interrupt to get new characters for buffer
+ NVIC_EnableIRQ(UART1_IRQn);
+ while (rx_in == rx_out) {
+ }
+// Start Critical Section - don't interrupt while changing global buffer variables
+ NVIC_DisableIRQ(UART1_IRQn);
+ }
+ rx_line[i] = rx_buffer[rx_out];
+ i++;
+ rx_out = (rx_out + 1) % buffer_size;
+ }
+ rx_line[i-1] = 0;
+// End Critical Section
+ NVIC_EnableIRQ(UART1_IRQn);
+ return;
+}
+
+// Interupt Routine to read in data from serial port
+void Rx_interrupt() {
+ led1=1;
+// Loop just in case more than one character is in UART's receive FIFO buffer
+// Stop if buffer full
+ while ((device.readable()) || (((rx_in + 1) % buffer_size) == rx_out)) {
+ rx_buffer[rx_in] = device.getc();
+// Uncomment to Echo to USB serial to watch data flow
+// monitor_device.putc(rx_buffer[rx_in]);
+ rx_in = (rx_in + 1) % buffer_size;
+ }
+ led1=0;
+ return;
+}
+
+// Interupt Routine to write out data to serial port
+void Tx_interrupt() {
+ led2=1;
+// Loop to fill more than one character in UART's transmit FIFO buffer
+// Stop if buffer empty
+ while ((device.writeable()) && (tx_in != tx_out)) {
+ device.putc(tx_buffer[tx_out]);
+ tx_out = (tx_out + 1) % buffer_size;
+ }
+ led2=0;
+ return;
+}
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