File content as of revision 1:b6f857ea3ce2:

#include "mbed.h"
#include "adns9800.h"

InterruptIn pulse(p8); // connects to FPGA and listens for start recording pulse
DigitalOut gndPin(p7);
DigitalOut ledPin(LED1);
ADNS9800 adns(p11,p12,p13,p10);
Serial pc(USBTX, USBRX);
int dx, dy, movementFlag, recFlag;
Ticker tmr;
uint32_t time_start, time_now, time_elapsed;

void displayRegisters()
{
  int oreg[4] = {0x00,0x3F,0x2A,0x02};
  char* oregname[] = {"Product_ID:","Inverse_Product_ID:","SROM_Version:","Motion:"};
  uint8_t regres;
  
  int rctr;
  
  for(rctr=0; rctr<4; rctr++){
    pc.printf("---\r\n");
    regres = adns.read_reg(oreg[rctr]);
    pc.printf(oregname[rctr]);
    pc.printf("%02x\r\n", regres);
    wait_ms(1);
  }
}

void read_motion()
{
    int motion, obs;
    adns.read_burst(&motion, &obs, &dx, &dy);
    if(recFlag == 1 && (dx > 0 || dy > 0))
    {
        time_now = us_ticker_read();
        time_elapsed = time_now - time_start;
        time_start = time_now;
        
        movementFlag = 1;
    }
}

void start_rec()
{
    recFlag = 1;
    ledPin = 1;
    time_start = us_ticker_read();
}

void stop_rec()
{
    ledPin = 0;
    recFlag = 0;
}

void format_and_send()
{
    // follow LSA's packet format
    /*
     * Data format from microblaze to PC:
     * 100000TT_0TTTTTTT_0TTTTTTT_0PXXXXXX_0PYYYYYY
     * Where T = delta timestamp, P = polarity, X = delta x, Y = delta y
     * Only first byte has MSB set
     * timestamp in 100us per increment
     * dx = 0(P)XXXXXX where 2nd bit is polarity
     */ 
     
     uint8_t outPkt[5];
     time_elapsed = time_elapsed / 100;
     
     outPkt[0] = 0x84 | ((time_elapsed >> 14) & 0x00000003);
     outPkt[1] = ((time_elapsed >> 7) & 0x0000007F);
     outPkt[2] = (time_elapsed & 0x0000007F);
     
     if(dx & 0x8000)
     {
         dx = (dx^0xFFFF) + 1;
         outPkt[3] = 0x40 | (dx & 0x3F); // negative
     }
     else
     {
         outPkt[3] = dx & 0x3F;
     }
     
     if(dy & 0x8000)
     {
         dy = (dy^0xFFFF) + 1;
         outPkt[4] = 0x40 | (dy & 0x3F);
     }
     else
     {
         outPkt[4] = dy & 0x3F;
     }
     
     // send packet
     for (int i=0; i<5; i++)
     {
        pc.putc(outPkt[i]);
     }        
}

int main() {
    gndPin = 0; // lazy to connect to true ground pin
    movementFlag = 0;
    recFlag = 0;
    
    pc.baud(115200);
    pc.printf("ADNS9800 test\r\n");
    
    adns.initialize();
    
    // display registers
    displayRegisters();
    
    pc.printf("Sensor initialized\r\n");
    
    // for sync with FPGA
    pulse.rise(&start_rec);
    pulse.fall(&stop_rec);
    
    tmr.attach_us(&read_motion, 1000); // timer interrupt to read registers
    
    while(1) {
        
        if(movementFlag == 1)
        {
            format_and_send();
            movementFlag = 0;
        }
    }
}