Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled - arduino-esp32

Question

I want to use timer interrupter combined with BLE to transmit in esp32.
I found that an error occurs when the transmission cycle is too fast.
I don't know what caused this error.
Help me plz.............................................................................................
The error
This is my code
#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
////////////////////////////////////////////////////////////
#include <BLE2902.h>
#define PERIOD_MS 5
#define BAUD_RATE 115200
#define BLE_WR_EN 0x5A
#define BLE_WR_DIS 0x55
#define SERVICE_UUID "0000ffe0-0000-1000-8000-00805f9b34fb"
#define CHARACTERISTIC_UUID_RX "0000ffe2-0000-1000-8000-00805f9b34fb"
#define CHARACTERISTIC_UUID_TX "0000ffe1-0000-1000-8000-00805f9b34fb"
int PERIOD_US=PERIOD_MS*1000;
/* create a hardware timer */
hw_timer_t * timer = NULL;
/* LED pin */
int led = 2;
/* LED state */
volatile byte state = LOW;
int i=0;
BLEServer *pServer;
BLEService *pService;
BLECharacteristic *pCharacteristic;
void IRAM_ATTR onTimer(){
//state = !state;
if(i<700){
i++;
}
else{
i=0;
}
//Serial.println(state);
char txString[8];
dtostrf(i, 1, 2, txString);
pCharacteristic->setValue(txString);
pCharacteristic->notify();
std::string txValue=pCharacteristic->getValue();
Serial.print("txValue:");
Serial.println(txValue.c_str());
//digitalWrite(led, state);
}
class MyServerCallbacks: public BLEServerCallbacks {
void onConnect(BLEServer* pServer) {
Serial.println("********************************");
Serial.println("Connected");
Serial.println("********************************");
timerAlarmEnable(timer);
};
void onDisconnect(BLEServer* pServer) {
Serial.println("********************************");
Serial.println("Disconnected");
Serial.println("********************************");
timerAlarmDisable(timer);
//delay(1000);
///*
// Start the service
//pService->start();
// Start advertising
//pServer->getAdvertising()->start();
pServer->startAdvertising();
//*/
//ESP.restart();
}
};
class MyCallbacks: public BLECharacteristicCallbacks {
void onWrite(BLECharacteristic *pCharacteristic) {
std::string rxValue = pCharacteristic->getValue();
std::string EN="Z";
std::string DIS="U";
Serial.print("rxValue:");
Serial.println(rxValue.c_str());
/*
//Serial.println(getvalue);
if (rxValue==EN ) {
//g_Timer.enable(g_TimerId);
timerAlarmEnable(timer);
digitalWrite(LED, HIGH);
}
else if (rxValue==DIS) {
//g_Timer.disable(g_TimerId);
timerAlarmDisable(timer);
//data_count = 0;
digitalWrite(LED, LOW);
}
*/
}
};
void setup() {
Serial.begin(115200);
Serial.begin(BAUD_RATE);
////////////////////////////////////////
Serial.println("Starting BLE Server!");
BLEDevice::init("ESP32-INTERRUT-Server");
/////////////////////////////////////////////////////////////////////////////////////
BLEServer *pServer = BLEDevice::createServer();
pServer->setCallbacks(new MyServerCallbacks());
// Create the BLE Service
BLEService *pService = pServer->createService(SERVICE_UUID);
// Create a BLE Characteristic
pCharacteristic = pService->createCharacteristic(
CHARACTERISTIC_UUID_TX,
BLECharacteristic::PROPERTY_READ|
BLECharacteristic::PROPERTY_NOTIFY
);
pCharacteristic->addDescriptor(new BLE2902());
BLECharacteristic *pCharacteristic = pService->createCharacteristic(
CHARACTERISTIC_UUID_RX,
BLECharacteristic::PROPERTY_WRITE
);
pCharacteristic->setCallbacks(new MyCallbacks());
// Start the service
pService->start();
// Start advertising
pServer->getAdvertising()->start();
////////////////////////////////////////////////////////////////////
timer = timerBegin(0, 80, true);
timerAttachInterrupt(timer, &onTimer, true);
timerAlarmWrite(timer, PERIOD_US, true);
timerAlarmDisable(timer);
}
void loop() {
}