Diff: main.cpp

Revision:

2:2244c8986987

Parent:

1:09b69f38fc73

Child:

3:0ff7b96f04b8

diff -r 09b69f38fc73 -r 2244c8986987 main.cpp
--- a/main.cpp	Thu May 12 11:12:47 2011 +0000
+++ b/main.cpp	Mon Aug 24 12:36:59 2015 +0000
@@ -1,56 +1,36 @@
-/*This is a program to output a sinwave in 12 bits 
-Digital to Analog converter MCP4922. Sampling frequency is 
-166,667Hz and produce an interrupt of Ticker every 6uS. 
-The Program calculates the data of the sinewave beforehand.
-*/
+
 #include "mbed.h"
-#include "TextLCD.h"
 #include "MCP4922.h"
 
-MCP4922 MCP(p5, p7,p8);  // MOSI, SCLK, CS
-TextLCD lcd(p24, p26, p27, p28, p29, p30);
-Ticker sampling;
-
-#define PI             3.141593
-#define MaxRes         800
-/// Global Variables
-unsigned int           OutData[MaxRes];
-unsigned int           Maxindex;
-unsigned long          Fsample;
-unsigned long          Freq;
-unsigned int           index = 0;
-
-void GenWave(void) {
-        unsigned int i;
+MCP4922 MCP(SPI_MOSI, SPI_SCK,SPI_CS);  // MOSI, SCLK, CS
 
-        Maxindex = (int) (Fsample / Freq);
-        if(Maxindex > MaxRes) {
-                Fsample = Freq * MaxRes;
-                     Maxindex = MaxRes;
-        }
-        for(i=0; i<Maxindex; i++) {
-                OutData[i] =  (int)(0x1FF * (1+ sin((2*PI*Freq*i)/Fsample))/2);
-        }
-}
-void timer_int(){
-        /// Output to D/A Converter
-        MCP.writeA(OutData[index]);
-        index++;
-        if(index >= Maxindex) index = 0;
-}
 
 /**** Main Function  ***/
-int main(void) {
-        MCP.frequency(20000000);
-
-        lcd.cls();
-        lcd.printf("MCP4922 Sinewave");
+int main(void)
+{
+    MCP.frequency(20000000);
 
-        Fsample = 166667;
-        Freq   = 1000;
-        GenWave();
-
-        sampling.attach_us(&timer_int, 6); 
-        while(1){
+    uint16_t i=0;
+    uint8_t state=0;
+    while(1) {
+        if(i < 0x0FFF)
+        {
+            i++;
+            
         }
+        else
+        {
+            i=0;
+            state = ~state;
+        }
+        
+        if(state ==0)
+        {
+            MCP.writeA(i);
+            }
+            else{
+           MCP.writeA( ((~i)+1)&0x0FFF);
+          }
+            wait_us(20);
+    }
 }
\ No newline at end of file