SPI read, write and command

Hi,

I've been looking at this code to try and convert to run an e-ink display (M5Paper) (https://github.com/gnzzz/IT8951/blob/89d505b26f130539644117522a0fdc128ffe44c1/lib/it8951.ts)

I'm pretty new to SPI so have been trying to figure it out.

looking through the forums I've managed to piece together 3 methods for reading, writing and sending commands

var read = function(reg,len) { // read
  return SPI1.send([reg|SPI_PREAMBLE.READ,new Uint8Array(len)], cs).slice(1);
};

var write = function(reg,data) { // write
    return SPI1.write(reg, data, cs);
};

var command = function(c,d) {
    SPI1.write(c, cs);
    if (d!==undefined) {
      dc.set();
      SPI1.write(d, cs);
    }
  }

But it doesn't work. So for example in the code I'm looking at, this gets called

 this.setRegister(SYS_REG.I80CPCR, 0x0001);
 this.spi.writeWords(
            Uint16Array.from([SPI_PREAMBLE.CMD, USDEF_I80_CMD.GET_DEV_INFO])
 );
 const data = this.spi.readWords(20);

I've converted this to:

write(SPI_PREAMBLE.WRITE|SYS_REG.I80CPCR, 0x0001);
let info = read(SPI_PREAMBLE.CMD|USDEF_I80_CMD.GET_DEV_INFO,20)

but info is just full of zeros.

I'm not sure if I'm totally on the wrong track or just missing some key bit of information.

Thanks,

Rob Smart