Pantid Chantangphol
/
MCP4922_Sinewave1
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MCP4922_Sinewave
by 
FRA221_2015
Revision 2:2244c8986987, committed 2015-08-24
- Comitter:
- soulx
- Date:
- Mon Aug 24 12:36:59 2015 +0000
- Parent:
- 1:09b69f38fc73
- Commit message:
- Triangle wave
Changed in this revision
--- a/MCP4922.h Thu May 12 11:12:47 2011 +0000 +++ b/MCP4922.h Mon Aug 24 12:36:59 2015 +0000 @@ -30,8 +30,8 @@ /* Reference: Microchip Technology (2005), MCP4821/MCP4822 DAC Data Sheet. */ // MCP4922 reference voltage. -#define MCP4922_VREF 2048 // Reference voltage (mV) -//#define MCP4922_VREF 3300 // Reference voltage (mV) +//#define MCP4922_VREF 2048 // Reference voltage (mV) +#define MCP4922_VREF 3300 // Reference voltage (mV) /* Define possible combinations of 16-bit command register bits */ #define MCP4922_REG_A1 0x3000 // Channel A gain 1
--- a/TextLCD.lib Thu May 12 11:12:47 2011 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +0,0 @@ -http://mbed.org/users/simon/code/TextLCD/#44f34c09bd37
--- 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
--- a/mbed.bld Thu May 12 11:12:47 2011 +0000 +++ b/mbed.bld Mon Aug 24 12:36:59 2015 +0000 @@ -1,1 +1,1 @@ -http://mbed.org/users/mbed_official/code/mbed/builds/63bcd7ba4912 +http://mbed.org/users/mbed_official/code/mbed/builds/8ed44a420e5c \ No newline at end of file