NRF24 questions

I am starting to use the NRF24... modules I got with the espruino and the master/slave example that I found in the code examples worked really great initially. I then modified the example of the master slightly:

SPI1.setup({sck:A5, miso:A6, mosi:A7});
var nrf = require("NRF24L01P").connect( SPI1, B0, B1 );
var counter = 0;
function onInit() {
  //transmit, receive
  nrf.init([0,0,0,0,2], [0,0,0,0,1]);
  
  setInterval(function() {
    nrf.sendCommand("" + counter++, function(r) { print("=="+r); });
  }, 1000);
}
onInit();
setInterval(function() {
  nrf.masterHandler();
}, 50);

It sends the counter variable to the slave, then prints the response. So ideally it will print the increasing numbers.

Two observations:

• when starting up, and once also just in the middle of runing the master code, I see

  TX not received 30
  TX not received 30
  ==@
  ==
   
  ==!B
  ==A
  ==8
  ==9
  ==
  ==15
  

• I sometimes get an empty response - the output from teh print is just == in this case. That seems simple to check against, just wondering what the issue is and if it could be fixed.

• after running this counter till around 600, I disconnected. then connected again and got a massive out of memory error. is this because of the print statement which might queue the output?

All output is below:

ERROR: Out of Memory!
WARNING: Out of memory while appending to array
INTERNAL ERROR: Timeout on SPI TX
ERROR: Out of Memory!
WARNING: Out of memory while appending to array
INTERNAL ERROR: Timeout on SPI TX
ERROR: Out of Memory!
WARNING: Out of memory while appending to array
INTERNAL ERROR: Timeout on SPI TX
ERROR: Out of Memory!
WARNING: Out of memory while appending to array
INTERNAL ERROR: Timeout on SPI TX
INTERNAL ERROR: Timeout on SPI RX
ERROR: Out of Memory!
WARNING: Out of memory while appending to array
INTERNAL ERROR: Timeout on SPI TX
INTERNAL ERROR: Timeout on SPI RX
ERROR: Out of Memory!
WARNING: Out of memory while appending to array
at line 1 col 144
{this.setReg(7,48);digitalWrite(this.CE,­0);this.setReg(0,10);this.spi.send(225,t­his.CSN);a=a.clone();a.splice(0,0,160);t­his.spi.send(a,this.CSN);digitalWrite(th­is.CE,1);for(a=1E3;a--&&!(this.getReg(7)­&48););0>=a&&print("TX timeout");a=!0;this.getReg(7)&16&&(print­("TX not received "+this.getReg(7)),a=!1);digitalWrite(thi­s.CE,0);this.setReg(0,11);digitalWrite(t­his.CE,1);this.setReg(7,48);return a}
                                                                                                                                                ^
in function "send" called from line 2 col 124
in function "sendString" called from line 1 col 42
in function "sendCommand" called from line 2 col 67
in function called from system
ERROR: Error processing interval - removing it.
Execution Interrupted during event processing.
ERROR: Out of Memory!
ERROR: Out of Me