File content as of revision 1:9c47e011f1bf:

/*            *************************************************************************************
              PGSE_diffusion Basic standard sequence, VERSION 1, October 24th 2012
              PULSE GRADIENT SPIN ECHO diffusion sequence(or diff_se) to measure diffusion coefficient value.
              ref : E.O. Stejskal and J.E. tanner, J. Chem. Phys. 42, 288 (1965)
              THE PGSE SEQUENCE IS
              1H ---> 90° -   DELTA/2 - 180   - DELTA/2  - FID
              Gz ---> --  - Gz(sdelta)- DELTA - Gz(sdelta)   
              *************************************************************************************
              Gradient strength (or duration) must be increase to measure the diffusion coefficient (2D DOSY spectroscopy)
              The maximum diffusion time (DELAT) is limited by T2 in PGSE.
              For T1 = T2 the PGSE sequence is usualy the easiest et preferred sequence.
              For T1 >> Té the PGSTE (PULSE GRADIENT with STIMULATED ECHO) is better, as during most of the diffusion
              time the magetization evolve prinipaly under T1 relaxtion (magnetization is like stored on Z axis in conventionnal NMR). With PGSTE the maximum
              diffusion time (DELTA) is limited by T1.
              IN THIS VERSION THE GRADIENT PULSE DURATION IS USED
              *************************************************************************************
                
                DESIGN FOR NXPLPC1768 ARM CORTEX M3 MCU BOARD:
                INPUT : NONE (reset on board)
                OUTPUT :  ACQU                  ---> P26 AND LED1
                       :  PULSES P1 & P2        ---> P25
                       :  Emmitter              ---> P24, P23
                       :  Transmitter           ---> P24, P23
                       :  gradient Z            ---> P21
              ***** IN THIS VERSION RECEIVER AND TRANSMITTER HAVE THE SAME PHASE CYCLE *****
              *************************************************************************************
              Alain LOUIS-JOSEPH
              CNRS
              Laboratoire de Physique de la Matière Condensée PMC
              Ecole Polytechnique
              91128 Palaiseau CEDEX France
              *************************************************************************************
                UNLESS OTHERWISE SPECIFIED THE PARAMETERS OF THE PULSE SEQUENCE ARE SET :
 D1           : relaxation delay ( ms to s)
 DELTA        : Diffusion time (ms to s)
 sdelta       :  Gradient duration
 D21          : delay of recovery
 DE           : fixed delay before acqusisition (not use)
 DW           : Dwell time period for sampled t2 acquisition time domain
 D0           : incremenatble delay ( from 1us to s)(t1 time domain dimension for 2D experiment)
 NS           : Number of scan
 NE           : Number of experiment
 VD           : Variable delay using a file list
 PW           : Pulse length (us)
 P90          : 90° transmitter or decoupler pulse length
 P180         : 180° transmitter or decoupler pulse length
 P3 P4        : 90°, 180°, X-nucleus pulses length
 DO           : Decoupler gated off or on
 HD           : HomoDecoupling in time sharing during acqusition
 HG           : HomoGating decoupling with receiver gated OFF
 BB           : Broadband modulation gate
 CW           : Continuous wave
 FID          : Free Induction Decay acquisition (data acquisition for time AQ
 AQ           : Acquisition time (physical t2  acquisition time domain dimension)
 PHn          : Phase for pulse number n (ie : PH1 for pulse P1)
 PH0          : Receiver phase
              *************************************************************************************
              
*/

#include "mbed.h"

#define D1  0.1               /*  Relaxation delay in second              */
#define Fs  48000                 /* Sample frequency in Hz                   */
#define DW  1                     /* DW time period in us    NOT USE              */
#define NS  1.0                   /* 8 accumulations                              */
#define DELTA  0.006              /*  diffusion dealy in s                         */
#define NE  1.0                   /* 8 accumulations  */
#define sdelta  0.003            /* gradient duration */
#define D21  0.001              /* recovery time */
#define AQ  0.04                  /* acquisition time in seconde     */
#define P90 0.00005             /* hard 90° 1H  */
//#define IncGsdelta 0.0           /* gradient width increment */
//#define stepG  0.0


DigitalOut Relaxation(LED1);    /* Delay on pin 26 ??? and flash LED1 during relaxation delay */
BusOut Acqu(p26, LED2)  ;       /*  Start acquisition */
DigitalOut  p1(p25);            // HARD PULSE
DigitalOut  p2(p25);            /* Only for reason of clarity P2 =2*P1 */
BusOut  PH1PH2(p24, p23) ;      // transmitter and receiver phases are the same
DigitalOut  Gsdelta(p22) ;           // Gradient Z

int main()
{

    // while (1) {
    p1 =0 ;
    Relaxation = 0 ;
    Acqu=0x00;
    PH1PH2=0x00;  //0 init

    for (float i = 0.0f ; i < NS ; i += 1.0f) {
        
        Relaxation = 1;         /* LED1 light*/
        wait(D1);               // relaxation
        Relaxation = 0;         // turn off the led

        p1=1;
        wait(P90);              // 90°
        p1=0;
        
        Gsdelta = 1;
        wait(sdelta); //gradient Z;
        Gsdelta = 0;
        
        wait(DELTA - sdelta);               // diffusion time 

        p2=1;
        wait(2*P90);            //180°
        p2=0;
        
        Gsdelta = 1;
        wait(sdelta); //gradient Z;
        Gsdelta = 0;
        
        
        wait(D21) ;             //recovery time

        Acqu=0x11;              // Acquire FID (we can write 3 in decimal)
        wait(AQ);
        Acqu=0x00;

        PH1PH2=PH1PH2+1;        //Phase cycling
        
        //IncGsdelta += stepG ;

        }
   
    }
//}

/* INCREMENTATION DE LA DUREE D'ECLAIREMENT DE LED1 AVEC PwmOut
PwmOut led(LED1);

int main() {
    while(1) {
        for(float p = 0.0f; p < 1.0f; p += 0.1f) {
            led = p;
            wait(0.1);
        }
    }
} */

/* Digital I/O

    DigitalOut - Configure and control a digital output pin.
    DigitalIn - Configure and control a digital input pin.
    DigitalInOut - Bi-directional digital pins

    BusIn - Flexible way to read multiple DigitalIn pins as one value
    BusOut - Flexible way to write multiple DigitalIn pins as one value
    BusInOut - Flexible way to read/write multiple DigitalIn pins as one value

    PortIn - Fast way to read multiple DigitalIn pins as one value
    PortOut - Fast way to write multiple DigitalIn pins as one value
    PortInOut - Fast way to read/write multiple DigitalIn pins as one value

    PwmOut - Pulse-width modulated output  */

/* Features

  NXP LPC1768 MCU
      High performance ARM® Cortex™-M3 Core
      96MHz, 32KB RAM, 512KB FLASH
      Ethernet, USB Host/Device, 2xSPI, 2xI2C, 3xUART, CAN, 6xPWM, 6xADC, GPIO
  Prototyping form-factor
      40-pin 0.1" pitch DIP package, 54x26mm
      5V USB or 4.5-9V supply
      Built-in USB drag 'n' drop FLASH programmer
  mbed.org Developer Website
      Lightweight Online Compiler
      High level C/C++ SDK
      Cookbook of published libraries and projects
      */