PS2 blocks communication with Arduino Serial Monitor

Using Arduino Programming Questions
1

I have arduino pro micro(disguised as leonardo) which communicates with PS2 trackpad and sends the data to computer(as a first step), but any PS2 communication blocks the serial monitor.

#include <ps2.h>

/*
   an arduino sketch to interface with a ps/2 mouse.
   Also uses serial protocol to talk back to the host
   and report what it finds.
*/

/*
   Pin 5 is the mouse data pin, pin 6 is the clock pin
   Feel free to use whatever pins are convenient.
*/
PS2 mouse(9, 10);

/*
   initialize the mouse. Reset it, and place it into remote
   mode, so we can get the encoder data on demand.
*/
void mouse_init()
{
  mouse.write(0xff);  // reset
  mouse.read();  // ack byte
  mouse.read();  // blank */
  mouse.read();  // blank */
  mouse.write(0xf0);  // remote mode
  mouse.read();  // ack
  delayMicroseconds(100);
}

void setup()
{
  Serial.begin(115200);
  while(!Serial);
  Serial.println("Hello");
  //mouse_init();
}

/*
   get a reading from the mouse and report it back to the
   host via the serial line.
*/
void loop()
{
  Serial.println("Hello again");
  /*char mstat;
  char mx;
  char my;
  char mz;

  mouse.write(0xeb);  // give me data!
  mouse.read();      // ignore ack
  mstat = mouse.read();
  mx = mouse.read();
  my = mouse.read();
  mz = mouse.read();


  Serial.begin(115200);
  while(!Serial);
  Serial.println(mstat, BIN);
  Serial.println("\tX=");
  Serial.println(mx, DEC);
  Serial.println("\tY=");
  Serial.println(my, DEC);
  Serial.println("\tZ=");
  Serial.println(mz, DEC);
  Serial.println();*/
  delay(1000);  /* twiddle */
}
2

You should never have Serial.begin() inside loop()!

3

That doesn't change anything. Serial monitor outputs only "Hello" and "Hello again"

4

Which ps2 library are you using?

5

That kind of library. Downloaded ps2.zip

6

That "Hello again" is not repeating, it only shows once in the Serial Monitor even though the command is in the loop function.

7

Bump.

8

I'm not familiar with the library or it's use. It does seem quite "old"; perhaps it has undergone "bit rot."

try adding debugging to see which (if any) of the ps2 calls is "hanging."

  mouse.write(0xeb);  // give me data!
  Serial.println("Send data request")'
  mouse.read();      // ignore ack
  Serial.println("read ack");
  mstat = mouse.read();
  Serial.println("read mstat");
  mx = mouse.read();
  Serial.println("read mx");
  // etc

Why is the call to mouse_init() commented out? While my experience is mostly with PS2 keyboards, I'm looking at https://isdaman.com/alsos/hardware/mouse/ps2interface.htm and it says that you should only be getting 4-byte mouse messages IF you've explicitly enabled "intelimouse" mode (and it doesn't look like the mouse_init() is doing that, even if you did call it. So you're probably only getting three-byte updates.)

9