Revision 2:16545dbc88ae, committed 2015-07-16

Comitter:

shreeshas95

Date:

Thu Jul 16 05:40:25 2015 +0000

Parent:

1:3cceef118195

Child:

3:972fa06ef0aa

Commit message:

SPI slave DMA read program for FRDMKL46Z , verified, working

Changed in this revision

--- a/dmaSPIslave.h	Thu Jul 16 05:19:02 2015 +0000
+++ b/dmaSPIslave.h	Thu Jul 16 05:40:25 2015 +0000
@@ -1,6 +1,11 @@
 #ifdef TARGET_KL46Z
 class dmaSPISlave : public SPISlave{
     public:
+/*
+@brief:     constructor : initialise the spi slave pins
+@param:     mosi, miso, sclk, ssel
+@return:    none
+*/
         dmaSPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel) : SPISlave(mosi, miso, sclk, ssel){
 //            trigger appropriate spi for dma
             if(_spi.spi == SPI0){
@@ -14,6 +19,13 @@
             read_dma.source(&_spi.spi->DL, false);
         }
         
+/*
+@brief:     initialise the dma buffer to store the recevied data
+@param:     read_data : pointer to the buffer
+            len : length in bytes to store in the buffer
+            fun : address of the function to attach to the dma interrupt, interrupt is called when the len num of bytes are written to the buffer
+@return:    none
+*/
         void bulkRead_init(uint8_t *read_data, int len, void (*fun)(void) ){
 //            acquire();
             _spi.spi->C2 |= SPI_C2_RXDMAE_MASK;
@@ -27,13 +39,27 @@
 //            attach interrupt function
             read_dma.attach(fun);
 
-//            _spi.spi->C2 &= ~(SPI_C2_RXDMAE_MASK);
         }
         
+/*
+@brief:     start the dma read process : has to be done everytime the buffer gets filled, can be used repeatedly
+@param:     none
+@return:    none
+*/
         void bulkRead_start(){
 //            start the read_dma
             read_dma.start(length);
         }
+
+/*
+@brief:     end dma process and return back to normal spi mode
+@param:     none
+@return:    none
+*/
+        void bulkRead_end(){
+//            turn off dma
+            _spi.spi->C2 &= ~(SPI_C2_RXDMAE_MASK);
+        }
         
     private:
         int length;

--- a/main.cpp	Thu Jul 16 05:19:02 2015 +0000
+++ b/main.cpp	Thu Jul 16 05:40:25 2015 +0000
@@ -1,5 +1,4 @@
 #include "mbed.h"
-#include "rtos.h"
 #include "SimpleDMA.h"
 #include "dmaSPIslave.h"
 
@@ -19,37 +18,27 @@
     pc.baud(9600);
     pc.printf("inside main\r\n");
     spi.format(8,0);
-//    spi.frequency(16000000);
+    spi.frequency(10000000);
     
     uint8_t buffer[PAYLOAD_LENGTH] = {0};
     pc.printf("welcome to dma test, start sending data now\r\n");
+
+//    initialise the buffer for dma
+    spi.bulkRead_init(buffer, PAYLOAD_LENGTH, &do_this);
+//    start dma read
+    spi.bulkRead_start();
     
-//    while(true){
-//        int i = 0;
-//        while(i < PAYLOAD_LENGTH){
-//            if(spi.receive()){
-//                buffer[i] = spi.read();
-//                ++i;
-//                ledg = !ledg;
-//            }
-//        }
-//        for(int i = 0 ; i < PAYLOAD_LENGTH ; ++i){
-//            pc.printf("%02x ", buffer[i]);
-//        }
-//        pc.printf("\r\n");
-//
-//    }
-
-    spi.bulkRead_init(buffer, PAYLOAD_LENGTH, &do_this);
-    spi.bulkRead_start();
     while(true){
         if(flag){
             flag = false;
             ledg = !ledg;
-            for(int i = 0 ; i < PAYLOAD_LENGTH ; ++i){
-                pc.printf("%02x ", buffer[i]);
-            }
-            pc.printf("\r\n");
+
+//            for(int i = 0 ; i < PAYLOAD_LENGTH ; ++i){
+//                pc.printf("%02x ", buffer[i]);
+//            }
+//            pc.printf("\r\n");
+
+//            start dma again after handling the data
             spi.bulkRead_start();
         }
     }