Diff: main.cpp

Revision:

0:b191e77dc856

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Feb 27 16:30:10 2012 +0000
@@ -0,0 +1,60 @@
+#include "mbed.h"
+
+
+SPI spi(p11, p12, p13); // mosi, miso, sclk
+DigitalOut cs(p14);
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+// Not possible to use inline assembler language with this device, error 1044
+/*#pragma arm
+void NOP()
+{
+  
+  __asm                    
+  {
+    NOP
+  }
+}
+#pragma thumb*/
+
+
+
+
+
+int main() {
+    // Setup the spi for 8 bit data, high steady state clock,
+    // second edge capture, with a 1MHz clock rate
+    spi.format(8,0);
+    spi.frequency(1000000);
+    int teste, result, b=0;
+    
+       
+    teste=0xAA;
+    
+    cs=0;
+    pc.printf("Answer before = %d\n\r", teste);
+    
+    
+    spi.write(teste);  
+        
+    cs=1;  // it's necessary to close and open the connection for the program to work, we believe that's necessary to exchange the buffer values 
+            // not exactly sure how much must this delay be
+    
+    if(b<1){} //  delay necessary between closing and opening a connection with the slave, we believe it's because of the high clock value of the mbed
+    
+    
+    
+    cs=0;
+    result=spi.write(0x00); // to read the value of the previous reply from the slave, it's necessary to make another write sending a dummy byte
+    cs=1;   
+    
+    
+    pc.printf("Answer later= 0x%X\n\r", result);   
+    // Maybe what is happening is that we need a bigger delay between the two writes so that it works the first time,maybe result is showing not the
+    //value of the previous write in this run of the program, but the value stored in the buffer in the previous run
+     
+        
+
+    
+}
\ No newline at end of file