How to use spi to write and read some specfic register address

Hi Robin,

Thank you very for replying and helping.

I set them to setInterval and that error does not occur anymore.

I believe I am using the hardware SPI and this is my SPI set up

function SPI_setup()
{
  SPI1.setup
  ({sck:A5,
     miso:A6,
     mosi:A7,
     baud: 10000000,
     mode: 0,
     order:'msb',
     bits:8
    });
}

The read time is to read the timestampes from the IMU, which is part of the data collection from the IMU.
the readtime Code looks like this:

function readtime(ss)
{
        hi = SPI_read(FIFO_DATA_OUT_L,ss);
        hi2 = SPI_read(FIFO_DATA_OUT_H,ss);
        non = SPI_read(FIFO_DATA_OUT_L,ss);
        lo = SPI_read(FIFO_DATA_OUT_H,ss);
        step = SPI_read(FIFO_DATA_OUT_L,ss);
        step = SPI_read(FIFO_DATA_OUT_H,ss);
        hi2 = hi2 << 16;
        hi = hi << 8;
        Value = hi2 | hi | lo;
        return Value;
}

I checked the time needed to collect one set of data is fixed at .029ms, IMU generate each set of data at 833Hz = 1/833 ~=0.0012, the time for the IMU to generate one set the data is a lot faster than the program excution. I think the problem is when the FIFO is full, the pattern will be messed up.

I am not very sure why PICO takes so long to read a set of data. I tried to look up the default system clock rate and it seems 84MHz already based on this E.setClock(Correct me if I am wrong), is there a way to improve the program execution/reading speed?

Changed version code

function extraction()
{
          st = getTime();
          s2 = SPI_read(FIFO_STATUS2,ss);
          if(((s2)&0b00010000) != 0b00010000)
          {
             console.log( omx = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              omy = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              omz = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              ax  = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              ay  = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              az  = read_FIFO(FIFO_DATA_OUT_H,FIFO_DATA_OUT_­L,ss),
              temp = read_FIFO(TEMP_OUT_H, TEMP_OUT_L, ss),
              tm = readtime(ss), getTime()-st);
          }
}

setInterval(extraction,0.00000000001);

Output:

///////////////The last number is the excution time//////////////
8273 -829 -15075 -77 -53 4231 -562 7840166 0.02954864501
6509 -2139 -9095 -88 -57 4253 -513 7840215 0.02941513061
5273 -2745 -8939 -86 -61 4244 -548 7840264 0.02940368652
4831 -2701 -8543 -84 -57 4250 -548 7840312 0.02936649322
4447 -2693 -8315 -89 -64 4251 -553 7840361 0.02934265136
4105 -2713 -7793 -85 -55 4250 -527 7840409 0.02941608428
3779 -2715 -6983 -86 -63 4240 -541 7840458 0.02939796447
3465 -2695 -5959 -90 -56 4245 -542 7840506 0.02937698364
////////////Data start to have wrong pattern//////////////
////////////Data start to have wrong pattern//////////////
3191 -2637 343 -267 -337 -45 -548 16699391 0.02938270568
-21 21 53 -9 255 43 -548 5888 0.02933788299
29 21 3 17 5 17 -541 4864 0.02938842773
-249 9 15 255 5 15 -535 4352 0.02937221527

Spi:

function SPI_write(addr,data,ss)
{
  SPI1.send([WRITE|addr,data],ss);       //write to address
}


function SPI_read(addr,ss)
{
  result=SPI1.send([addr|READ,0x00],ss)[1]­;
  return result;
}