fra221-pb11 / Mbed 2 deprecated Lab4MCP492_SPI

lab4 using referenced voltage from knob and generate voltage output from DAC mcp4922

Dependencies:   mbed

main.cpp@0:bdf668d4c05b, 2018-11-02 (annotated)

Committer:
sippasaeng
Date:
Fri Nov 02 02:15:49 2018 +0000
Revision:
0:bdf668d4c05b
Child:
1:b81dc534e7d7
1st version;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sippasaeng 0:bdf668d4c05b 1 #include "mbed.h"
sippasaeng 0:bdf668d4c05b 2 #include "math.h"
sippasaeng 0:bdf668d4c05b 3 /**********************
sippasaeng 0:bdf668d4c05b 4 * MCP4922
sippasaeng 0:bdf668d4c05b 5 **********************/
sippasaeng 0:bdf668d4c05b 6
sippasaeng 0:bdf668d4c05b 7 ///SPI Interface
sippasaeng 0:bdf668d4c05b 8 SPI MCP4922_SPI(D11,D12,D13);//MOSI ,MISO ,SCK
sippasaeng 0:bdf668d4c05b 9 DigitalOut MCP4922_CS(D7);//CS
sippasaeng 0:bdf668d4c05b 10
sippasaeng 0:bdf668d4c05b 11
sippasaeng 0:bdf668d4c05b 12
sippasaeng 0:bdf668d4c05b 13 //Digital Output
sippasaeng 0:bdf668d4c05b 14 DigitalOut MCP4922_LDAC(D4);
sippasaeng 0:bdf668d4c05b 15 DigitalOut MCP4922_SHDN(D6);
sippasaeng 0:bdf668d4c05b 16 void volt_out(double volt)
sippasaeng 0:bdf668d4c05b 17 {
sippasaeng 0:bdf668d4c05b 18
sippasaeng 0:bdf668d4c05b 19 uint16_t temp=((uint16_t)(volt*4096/3.33))&0x0fff;
sippasaeng 0:bdf668d4c05b 20 uint16_t MCP4922_Sent_Data = 0;
sippasaeng 0:bdf668d4c05b 21 MCP4922_Sent_Data = 0x3000|temp;
sippasaeng 0:bdf668d4c05b 22 //MCP4922_Sent_Data = 0x3fff;
sippasaeng 0:bdf668d4c05b 23 MCP4922_CS = 0;
sippasaeng 0:bdf668d4c05b 24
sippasaeng 0:bdf668d4c05b 25
sippasaeng 0:bdf668d4c05b 26 //sent data buffer to mcp4922
sippasaeng 0:bdf668d4c05b 27 MCP4922_SPI.write(MCP4922_Sent_Data);
sippasaeng 0:bdf668d4c05b 28
sippasaeng 0:bdf668d4c05b 29 //set CS to High to End MCP4922 SPI Interface
sippasaeng 0:bdf668d4c05b 30 MCP4922_CS = 1;
sippasaeng 0:bdf668d4c05b 31
sippasaeng 0:bdf668d4c05b 32 //set LDAC to LOW to Load data to output
sippasaeng 0:bdf668d4c05b 33 MCP4922_LDAC = 0 ;
sippasaeng 0:bdf668d4c05b 34
sippasaeng 0:bdf668d4c05b 35 //wait at least 100ns = 0.1 microsec ..... So set at 1 microsec
sippasaeng 0:bdf668d4c05b 36 wait_us(1);
sippasaeng 0:bdf668d4c05b 37
sippasaeng 0:bdf668d4c05b 38 //set LDAC to High to prepare next output
sippasaeng 0:bdf668d4c05b 39 MCP4922_LDAC = 1 ;
sippasaeng 0:bdf668d4c05b 40 }
sippasaeng 0:bdf668d4c05b 41 int main()
sippasaeng 0:bdf668d4c05b 42 {
sippasaeng 0:bdf668d4c05b 43 /******************************
sippasaeng 0:bdf668d4c05b 44 ***** setup *******
sippasaeng 0:bdf668d4c05b 45 ******************************/
sippasaeng 0:bdf668d4c05b 46
sippasaeng 0:bdf668d4c05b 47 /////////setup SPI//////////
sippasaeng 0:bdf668d4c05b 48 //set CS High
sippasaeng 0:bdf668d4c05b 49 MCP4922_CS=1;
sippasaeng 0:bdf668d4c05b 50
sippasaeng 0:bdf668d4c05b 51 //set SPI mode [1,1]=> mode 3 @16bit
sippasaeng 0:bdf668d4c05b 52 MCP4922_SPI.format(16,3);
sippasaeng 0:bdf668d4c05b 53
sippasaeng 0:bdf668d4c05b 54 //set SPI Frequency @20MHz
sippasaeng 0:bdf668d4c05b 55 MCP4922_SPI.frequency(20000000);
sippasaeng 0:bdf668d4c05b 56
sippasaeng 0:bdf668d4c05b 57 //set Load DAC High (inactive)
sippasaeng 0:bdf668d4c05b 58 MCP4922_LDAC = 1;
sippasaeng 0:bdf668d4c05b 59
sippasaeng 0:bdf668d4c05b 60 //set shutdown DAC High (inactive)
sippasaeng 0:bdf668d4c05b 61 MCP4922_SHDN = 1;
sippasaeng 0:bdf668d4c05b 62
sippasaeng 0:bdf668d4c05b 63 //loop
sippasaeng 0:bdf668d4c05b 64 while(1) {
sippasaeng 0:bdf668d4c05b 65 for(double x=0; x<2*3.141592; x+=0.00001) {
sippasaeng 0:bdf668d4c05b 66 volt_out((sin(x)+1.00)*3.33/2.00);
sippasaeng 0:bdf668d4c05b 67 }
sippasaeng 0:bdf668d4c05b 68
sippasaeng 0:bdf668d4c05b 69 }
sippasaeng 0:bdf668d4c05b 70 }