SPI Communication between ESP32S3

Question

I have two Esp32S3-WROOM-1 DevKits and I'm trying to communicate both with SPI, one slave and other master. I'm using Arduino IDE to do it.

I am connecting the wires like this:

Master	Slave
PIN9/GPIO10 - CS	PIN9/GPIO10 - CS
PIN10/GPIO11 - MOSI	PIN10/GPIO11 - MOSI
PIN11/GPIO12 - SCK	PIN11/GPIO12 - SCK
PIN12/GPIO13 - MISO	PIN12/GPIO13 - MISO

The codes I'm using:

slave

#include <SPI.h>

volatile bool receivedFlag = false;
volatile byte receivedData = 0;

static const int spiClk = 1000000;

void IRAM_ATTR ssInterrupt() {
  if (digitalRead(SS) == LOW) {
    SPI.beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
    receivedData = SPI.transfer(0x00);
    receivedFlag = true;
    SPI.endTransaction();
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(SS, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(SS), ssInterrupt, FALLING);
  SPI.begin(SCK, MISO, MOSI, SS); // Inicia o SPI como slave
}

void loop() {
  if (receivedFlag) {
    Serial.print("Received: ");
    Serial.println(receivedData);
    receivedFlag = false;
  }
}

master

#include <SPI.h>

#define SS_PIN 10

static const int spiClk = 1000000;

void setup() {
  Serial.begin(115200);
  pinMode(SS_PIN, OUTPUT);
  SPI.begin(SCK, MISO, MOSI, SS);
}

void loop() {
  SPI.beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
  digitalWrite(SS_PIN, LOW);
  SPI.transfer(0x45);
  digitalWrite(SS_PIN, HIGH);
  SPI.endTransaction();

  delay(1000);
}

With Serial Monitor on Slave it just show Received: 0.

Can somebody help me what I'm doing wrong?

Thanks.