After configuring SPI communication for SAMD51 enable function freezes the setup - c++

Question

I am currently working to configurate SPI communication in a SAMD51 board. After a lot of research I could find how to setup the registers to start the pin configuration and clock setup, among other things. But there is one procedure in the end of the setup that requires to enable the pin again.
Here is the datasheet for the MCU https://www.mouser.com/datasheet/2/268/60001507A-1130176.pdf
SERCOM4->SPI.CTRLA.bit.ENABLE = 1;
After I call this line the library freezes and I cannot get any other response.
find bellow the cpp file.
#include "SercomSPISlave.h"
// Constructors //
SercomSPISlave::SercomSPISlave()
{
}
// Public Methods //
void SercomSPISlave::Sercom4init()
{
//Setting up NVIC
NVIC_EnableIRQ(SERCOM4_0_IRQn);
NVIC_SetPriority(SERCOM4_0_IRQn,2);
//MCLK->APBDMASK.reg |= MCLK_APBDMASK_SERCOM4;
MCLK->APBDMASK.bit.SERCOM4_ = 1;
//Setting Generic Clock Controller!!!!
//GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(GCM_SERCOM4_CORE) | //Generic Clock 0
// GCLK_CLKCTRL_GEN_GCLK0 | // Generic Clock Generator 0 is the source
// GCLK_CLKCTRL_CLKEN; // Enable Generic Clock Generator
GCLK->PCHCTRL[34].reg = GCLK_PCHCTRL_GEN_GCLK0 | GCLK_PCHCTRL_CHEN;
//while(GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY); //Wait for synchronisation
//Configure SERCOM4 SPI PINS
//Set PA12 as input (MOSI) - on D22 / MISO
//Set PB09 as input (SCK) - on A2
//Set PB10 as input (SS) - on D23 / MOSI
//Set PB11 as output (MISO) - on D24 / SCK
PORT->Group[PORTB].PINCFG[11].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB11
PORT->Group[PORTB].PMUX[11 >> 1].bit.PMUXO = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
PORT->Group[PORTB].PINCFG[12].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB12
PORT->Group[PORTB].PMUX[12 >> 1].bit.PMUXE = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
PORT->Group[PORTB].PINCFG[13].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB13
PORT->Group[PORTB].PMUX[13 >> 1].bit.PMUXO = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
PORT->Group[PORTA].PINCFG[9].bit.PMUXEN = 0x1; //Enable Peripheral Multiplexing for SERCOM4 SPI PB09
PORT->Group[PORTA].PMUX[9 >> 1].bit.PMUXO = 0x3; //SERCOM 4 is selected for peripheral use of this pad (0x3 selects peripheral function D: SERCOM-ALT)
/*
Explanation:
PMUXEN stands for Peripheral Multiplexing Enable
PMUXE stands for Even bits in the Peripheral Multiplexing register
PMUXO stands for Odd bits in the Peripheral Multiplexing register
The selection of peripheral function A to H is done by writing to the Peripheral Multiplexing Odd and Even bits in the Peripheral Multiplexing register (PMUXn.PMUXE/O) in the PORT.
Reference: Atmel-42181G-SAM-D21_Datasheet section 6.1 on page 21
PA12 corresponds to: PORTA, PMUX[6] Even
PB09 corresponds to: PORTB, PMUX[4] Odd
PB10 corresponds to: PORTB, PMUX[5] Even
PB11 corresponds to: PORTB, PMUX[5] Odd
In general:
Px(2n+0/1) corresponds to Portx, PMUX[n] Even=0/Odd=1*/
//Disable SPI 1
SERCOM4->SPI.CTRLA.bit.ENABLE =0;
while(SERCOM4->SPI.SYNCBUSY.bit.ENABLE);
//Reset SPI 1
SERCOM4->SPI.CTRLA.bit.SWRST = 1;
while(SERCOM4->SPI.CTRLA.bit.SWRST || SERCOM4->SPI.SYNCBUSY.bit.SWRST);
//Set up SPI Control A Register
SERCOM4->SPI.CTRLA.bit.DORD = 0; //MSB first
SERCOM4->SPI.CTRLA.bit.CPOL = 0; //SCK is low when idle, leading edge is rising edge
SERCOM4->SPI.CTRLA.bit.CPHA = 0; //data sampled on leading sck edge and changed on a trailing sck edge
SERCOM4->SPI.CTRLA.bit.FORM = 0x0; //Frame format = SPI
SERCOM4->SPI.CTRLA.bit.DIPO = 0x0; //DATA PAD0 MOSI is used as slave input (slave mode) // page 492
SERCOM4->SPI.CTRLA.bit.DOPO = 0x2; //DATA PAD2 MISO is used as slave output
SERCOM4->SPI.CTRLA.bit.MODE = 0x2; //SPI in Slave mode
SERCOM4->SPI.CTRLA.bit.IBON = 0x1; //Buffer Overflow notification
SERCOM4->SPI.CTRLA.bit.RUNSTDBY = 1; //wake on receiver complete
//Set up SPI control B register
//SERCOM4->SPI.CTRLB.bit.RXEN = 0x1; //Enable Receiver
SERCOM4->SPI.CTRLB.bit.SSDE = 0x1; //Slave Selecte Detection Enabled
SERCOM4->SPI.CTRLB.bit.CHSIZE = 0; //character size 8 Bit
//SERCOM4->SPI.CTRLB.bit.PLOADEN = 0x1; //Enable Preload Data Register
//while (SERCOM4->SPI.SYNCBUSY.bit.CTRLB);
//Set up SPI interrupts
SERCOM4->SPI.INTENSET.bit.SSL = 0x1; //Enable Slave Select low interrupt
SERCOM4->SPI.INTENSET.bit.RXC = 0x1; //Receive complete interrupt
SERCOM4->SPI.INTENSET.bit.TXC = 0x1; //Receive complete interrupt
SERCOM4->SPI.INTENSET.bit.ERROR = 0x1; //Receive complete interrupt
SERCOM4->SPI.INTENSET.bit.DRE = 0x1; //Data Register Empty interrupt
//init SPI CLK
//SERCOM4->SPI.BAUD.reg = SERCOM_FREQ_REF / (2*4000000u)-1;
//Enable SPI
SERCOM4->SPI.CTRLB.bit.RXEN = 0x1; //Enable Receiver, this is done here due to errate issue
while(SERCOM4->SPI.SYNCBUSY.bit.CTRLB); //wait until receiver is enabled
Serial.begin(115200);
SERCOM4->SPI.CTRLA.bit.ENABLE = 1;
Serial.print(SERCOM4->SPI.CTRLA.bit.ENABLE);
while(SERCOM4->SPI.SYNCBUSY.bit.ENABLE);
}
Find bellow the .h file.
#ifndef SercomSPISlave_h
#define SercomSPISlave_h
#include <Arduino.h>
class SercomSPISlave
{
public:
// Constructors //
SercomSPISlave();
// Public Methods //
void Sercom4init();
};
#endif
Find bellow the .ino code
#include <SercomSPISlave.h>
SercomSPISlave SPISlave;
void setup()
{
Serial.begin(115200);
Serial.println("Serial started");
SPISlave.Sercom4init();
while(!Serial);
Serial.println("Sercom1 SPI slave initialized!");
}
void loop()
{
}
I appreciate any support you can give me.