main.cpp

00001 #include "mbed.h"
00002 #include <stdio.h>
00003 
00004 #include "MAX2871.h"
00005 
00006 int main() {
00007     
00008 #define D6   P0_6
00009 #define D8   P1_4
00010 #define D9   P1_5
00011 #define D10  P1_3
00012 #define D11  P1_1
00013 #define D12  P1_2
00014 #define D13  P1_0
00015 
00016     
00017     SPI         spi(D11,D12,D13);           //mosi, miso, sclk
00018     Serial      pc(USBTX,USBRX,9600);       //tx, rx, baud
00019 
00020     DigitalOut  le(D10,1);                  //Latch enable pin for MAX2871
00021     DigitalIn   ld(D6);                     //Lock detect output pin
00022     DigitalOut  led(LED_BLUE,1);            //blue LED on MAX32600MBED board
00023 
00024     DigitalOut  rfouten(D8,1);              //RF output enable pin
00025     DigitalOut  ce(D9,1);                   //Chip enable pin 
00026     
00027     double freq_entry;                  //variable to store user frequency input
00028     char buffer[256];                   //array to hold string input from terminal
00029     
00030     double v_tune, temperature;         //stores TUNE voltage and die temperature of MAX2871
00031     uint32_t vco;                       //stores active VCO in use
00032     double freq_rfouta;                 //variable to calculate ouput frequency from register settings
00033     
00034     spi.format(8,0);                    //CPOL = CPHA = 0, 8 bits per frame
00035     spi.frequency(1000000);             //1 MHz SPI clock
00036 
00037     MAX2871 max2871(spi,D10);           //create object of class MAX2871, assign latch enable pin
00038     
00039     max2871.powerOn(true);              //set all hardware enable pins and deassert software shutdown bits
00040     
00041     max2871.setPFD(50.0,2);             //inputs are reference frequency and R divider to set phase/frequency detector comparison frequency
00042     
00043     //The routine in the while(1) loop will ask the user to input a desired
00044     //output frequency, check that it is in range, calculate the corresponding
00045     //register settings, update the MAX2871 registers, and then independently
00046     //use the programmed values to re-calculate the output frequency chosen
00047     while(1){
00048         pc.printf("\n\rEnter a frequency in MHz:");
00049         fgets(buffer,256,stdin);  
00050          pc.printf("Line: %s\n", buffer);                          //store entry as string until newline entered
00051         freq_entry = floor(1000*atof(buffer))/1000;         //convert string to a float with 1kHz precision
00052         if((freq_entry < 23.5) || (freq_entry > 6000.0))    //check the entered frequency is in MAX2871 range
00053             pc.printf("\n\rNot a valid frequency entry.");  
00054         else
00055         {
00056             pc.printf("\n\rTarget: %.3f MHz",freq_entry);   //report the frequency derived from user's input
00057             max2871.setRFOUTA(freq_entry);                  //update MAX2871 registers for new frequency
00058 
00059             while(!ld)                                      //blink an LED while waiting for MAX2871 lock detect signal to assert
00060             {
00061                 led = !led;
00062                 wait_ms(30);
00063             }
00064             led = 1;
00065         
00066             vco = max2871.readVCO();                        //read the active VCO from MAX2871
00067             v_tune = max2871.readADC();                     //read the digitized TUNE voltage
00068             freq_rfouta = max2871.getRFOUTA();              //calculate the output frequency of channel A
00069             temperature = max2871.readTEMP();               //read die temperature from MAX2871
00070 
00071             //print the achieved output frequency and MAX2871 diagnostics
00072             pc.printf("\n\rActual: %.3f MHz",freq_rfouta);
00073             pc.printf("\n\rVTUNE: %.3f V, VCO: %d, TEMP: %f",v_tune,vco,temperature);
00074         }
00075     }   
00076 }