Erik - / Mbed 2 deprecated SimpleDMA_HelloWorld

HelloWorld program showing SimpleDMA with mainly UART stuff

Dependencies:   SimpleDMA mbed-rtos mbed

main.cpp@1:418889681f13, 2014-01-04 (annotated)

Committer:
Sissors
Date:
Sat Jan 04 14:58:41 2014 +0000
Revision:
1:418889681f13
Parent:
0:cf18a31facd6 
LPC1768 support added

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Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:cf18a31facd6 1 #include "mbed.h"
Sissors 0:cf18a31facd6 2 #include "rtos.h"
Sissors 0:cf18a31facd6 3 #include "SimpleDMA.h"
Sissors 0:cf18a31facd6 4
Sissors 0:cf18a31facd6 5 DigitalOut led1(LED1);
Sissors 1:418889681f13 6 SimpleDMA dma(0);
Sissors 0:cf18a31facd6 7 RawSerial pc(USBTX, USBRX);
Sissors 0:cf18a31facd6 8
Sissors 0:cf18a31facd6 9 void callback(void) {
Sissors 0:cf18a31facd6 10 pc.printf("Callback!\r\n");
Sissors 0:cf18a31facd6 11 }
Sissors 0:cf18a31facd6 12
Sissors 0:cf18a31facd6 13 void led_thread(void const *args) {
Sissors 0:cf18a31facd6 14
Sissors 0:cf18a31facd6 15 while (true) {
Sissors 0:cf18a31facd6 16 led1 = !led1;
Sissors 0:cf18a31facd6 17 Thread::wait(300);
Sissors 0:cf18a31facd6 18 }
Sissors 0:cf18a31facd6 19 }
Sissors 0:cf18a31facd6 20
Sissors 0:cf18a31facd6 21
Sissors 0:cf18a31facd6 22 int main() {
Sissors 0:cf18a31facd6 23 printf("Start\r\n");
Sissors 0:cf18a31facd6 24
Sissors 0:cf18a31facd6 25 printf("Use DMA to send 10 characters from buffer to buffer\r\n");
Sissors 0:cf18a31facd6 26 printf("Then send them to UART0 (PC)\r\n");
Sissors 0:cf18a31facd6 27
Sissors 0:cf18a31facd6 28 char characters[] = "abcdefgh\r\n"; //Characters we send
Sissors 0:cf18a31facd6 29 char characters2[11]; //Second buffer
Sissors 0:cf18a31facd6 30
Sissors 0:cf18a31facd6 31 //Set source and destination, second argument is true since
Sissors 0:cf18a31facd6 32 //we should run through both arrays
Sissors 0:cf18a31facd6 33 dma.source(characters, true);
Sissors 0:cf18a31facd6 34 dma.destination(characters2, true);
Sissors 0:cf18a31facd6 35 //dma.attach(callback);
Sissors 0:cf18a31facd6 36 //Start transfer of 10 characters
Sissors 0:cf18a31facd6 37 dma.start(10);
Sissors 0:cf18a31facd6 38
Sissors 0:cf18a31facd6 39 while(dma.isBusy());
Sissors 0:cf18a31facd6 40
Sissors 0:cf18a31facd6 41 //Now to UART, enable DMA in UART, destination is now
Sissors 0:cf18a31facd6 42 //a fixed address, so address pointer should not be incremented,
Sissors 0:cf18a31facd6 43 //thus second argument is false. Also set trigger to UART0_RX.
Sissors 1:418889681f13 44 //This sends a new value to the UART as soon as it is possible
Sissors 1:418889681f13 45 #ifdef TARGET_LPC1768
Sissors 1:418889681f13 46 LPC_UART0->FCR |= 1<<3;
Sissors 1:418889681f13 47 dma.destination(&LPC_UART0->THR, false);
Sissors 1:418889681f13 48 #endif
Sissors 1:418889681f13 49 #ifdef TARGET_KL25Z
Sissors 0:cf18a31facd6 50 UART0->C5 |= (1<<7) | (1<<5);
Sissors 1:418889681f13 51 dma.destination(&UART0->D, false);
Sissors 1:418889681f13 52 #endif
Sissors 0:cf18a31facd6 53 dma.source(characters2, true);
Sissors 0:cf18a31facd6 54 dma.trigger(Trigger_UART0_TX);
Sissors 0:cf18a31facd6 55
Sissors 0:cf18a31facd6 56 dma.start(10);
Sissors 0:cf18a31facd6 57 while(dma.isBusy());
Sissors 0:cf18a31facd6 58
Sissors 0:cf18a31facd6 59 printf("\r\n\nNow to show if it doesn't increment the address\r\n");
Sissors 0:cf18a31facd6 60 printf("Also we attach a callback\r\n");
Sissors 0:cf18a31facd6 61 dma.source(characters2, false);
Sissors 0:cf18a31facd6 62 dma.attach(callback);
Sissors 0:cf18a31facd6 63 dma.start(10);
Sissors 0:cf18a31facd6 64 while(dma.isBusy());
Sissors 0:cf18a31facd6 65
Sissors 0:cf18a31facd6 66
Sissors 0:cf18a31facd6 67 printf("\r\n\nFinally we make it a loopback, and use RTOS\r\n");
Sissors 0:cf18a31facd6 68 printf("The LED in another thread continues blinking while DMA send is busy\r\n");
Sissors 0:cf18a31facd6 69
Sissors 0:cf18a31facd6 70 //Make a thread with low priority, to show main thread with DMA gives way to other thread while busy sending
Sissors 0:cf18a31facd6 71 Thread thread(led_thread);
Sissors 0:cf18a31facd6 72 thread.set_priority(osPriorityLow);
Sissors 0:cf18a31facd6 73
Sissors 1:418889681f13 74 #ifdef TARGET_LPC1768
Sissors 1:418889681f13 75 dma.source(&LPC_UART0->THR, false);
Sissors 1:418889681f13 76 #endif
Sissors 1:418889681f13 77 #ifdef TARGET_KL25Z
Sissors 0:cf18a31facd6 78 dma.source(&UART0->D, false);
Sissors 1:418889681f13 79 #endif
Sissors 1:418889681f13 80
Sissors 0:cf18a31facd6 81 //Trigger is now the receiving on the UART
Sissors 0:cf18a31facd6 82 dma.trigger(Trigger_UART0_RX);
Sissors 0:cf18a31facd6 83
Sissors 0:cf18a31facd6 84 //dma.wait blocks the current Thread until finished while allowing other threads to run
Sissors 0:cf18a31facd6 85 dma.wait(10);
Sissors 0:cf18a31facd6 86
Sissors 0:cf18a31facd6 87 printf("\r\n\nFinished :-)\r\n");
Sissors 0:cf18a31facd6 88
Sissors 0:cf18a31facd6 89 //Notice the LED doesn't blink now, since this thread uses all resources in while(1)
Sissors 0:cf18a31facd6 90 while(1);
Sissors 0:cf18a31facd6 91 }