Erik -
HelloWorld program showing SimpleDMA with mainly UART stuff
Dependencies: SimpleDMA mbed-rtos mbed
Revision 0:cf18a31facd6, committed 2013-12-26
- Comitter:
- Sissors
- Date:
- Thu Dec 26 16:32:59 2013 +0000
- Child:
- 1:418889681f13
- Commit message:
- v1.0
;
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/SimpleDMA.lib Thu Dec 26 16:32:59 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/Sissors/code/SimpleDMA/#c3a84c6c432c
--- /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);
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-rtos.lib Thu Dec 26 16:32:59 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed-rtos/#ee87e782d34f
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Thu Dec 26 16:32:59 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/dc225afb6914 \ No newline at end of file