Diff: main.cpp

Revision:

0:cf18a31facd6

Child:

1:418889681f13

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Dec 26 16:32:59 2013 +0000
@@ -0,0 +1,79 @@
+#include "mbed.h"
+#include "rtos.h"
+#include "SimpleDMA.h"
+
+DigitalOut led1(LED1);
+SimpleDMA dma;
+RawSerial pc(USBTX, USBRX);
+
+void callback(void) {
+    pc.printf("Callback!\r\n");
+    }
+
+void led_thread(void const *args) {
+    
+    while (true) {
+        led1 = !led1;
+        Thread::wait(300);
+    }
+}
+
+
+int main() {
+    printf("Start\r\n");
+    
+    printf("Use DMA to send 10 characters from buffer to buffer\r\n");
+    printf("Then send them to UART0 (PC)\r\n");
+    
+    char characters[] = "abcdefgh\r\n";     //Characters we send
+    char characters2[11];                   //Second buffer
+    
+    //Set source and destination, second argument is true since
+    //we should run through both arrays
+    dma.source(characters, true);
+    dma.destination(characters2, true);
+    //dma.attach(callback);
+    //Start transfer of 10 characters
+    dma.start(10);
+    
+    while(dma.isBusy());
+    
+    //Now to UART, enable DMA in UART, destination is now
+    //a fixed address, so address pointer should not be incremented,
+    //thus second argument is false. Also set trigger to UART0_RX.
+    //This sends a new value to the UART as soon as it is possible    
+    UART0->C5 |= (1<<7) | (1<<5);
+    dma.source(characters2, true);
+    dma.destination(&UART0->D, false);
+    dma.trigger(Trigger_UART0_TX);
+
+    dma.start(10);
+    while(dma.isBusy());      
+    
+    printf("\r\n\nNow to show if it doesn't increment the address\r\n");
+    printf("Also we attach a callback\r\n");
+    dma.source(characters2, false);
+    dma.attach(callback);
+    dma.start(10);
+    while(dma.isBusy());  
+
+    
+    printf("\r\n\nFinally we make it a loopback, and use RTOS\r\n");
+    printf("The LED in another thread continues blinking while DMA send is busy\r\n");
+    
+    //Make a thread with low priority, to show main thread with DMA gives way to other thread while busy sending
+    Thread thread(led_thread);
+    thread.set_priority(osPriorityLow);
+    
+    dma.source(&UART0->D, false);
+    //Trigger is now the receiving on the UART
+    dma.trigger(Trigger_UART0_RX);
+    
+    //dma.wait blocks the current Thread until finished while allowing other threads to run
+    dma.wait(10);
+    
+    printf("\r\n\nFinished :-)\r\n");
+    
+    //Notice the LED doesn't blink now, since this thread uses all resources in while(1)
+    while(1);
+}