NFC Reader for FreeStyle Libre with BM019 - Unofficial board?

Results...

Using this code...

function echo(){
    var r=spi.send(0x55,SS_PIN);
   print("echo response:",r);
}

Gives me this...

echo response:  6
echo response:  0
echo response:  0
echo response:  0
echo response:  0
echo response:  0
echo response:  85
echo response:  85
echo response:  255
echo response:  255
echo response:  255
echo response:  255
echo response:  255

Tried the inventory function as written above and got lots of these (while scanning a tag)...

Got data new Uint8Array(0)

I think it might be necessary to set the NFC protocol before doing this.
Anyway, you have helped in confirming I haven't been doing anything really silly, which is really want I wanted. Fresh eyes.