I had the same problem before, because LOW vol (i used 1 diot ) ...just check power is 3.3v in put for esp32. Then check the current power too to make sure it have normal power working.

Thanks Loboris for your recommend, i think you are right.

Thanks WIFIVE so much, that topics pretty hard with newbie like me. Can you write a example code to use eaier , i just want use this PSRAM to save bounch of bytes array , read and write single byte at a adress cell . PLease help me WIFIVE im still waiting for your help.

I'm waiting...lalala

https://www.cnx-software.com/wp-content/uploads/2016/12/ESP32-WROVER.jpg
As i know ESP32-WROVER has 4 mega bytes external PSRAM,very use full and it cost not too much ,so i decide to buy a module in the future, but now i can't found any examples or information to use this 4MB SRAM on it. Can any ...

Here is my code, just Examples.:
uint8_t b[130000];// 130k bytes

void setup() {
Serial.begin(9600);

}

void loop() {
Serial.println("Ok !");
b[1]=0;
delay(1000);
}

"Sketch uses 105,566 bytes (10%) of program storage space. Maximum is 1,044,464 bytes.
Global variables use 139,492 bytes (47%) of ...

Easy , just use number on the ESP32 board.
Ex: if you want use D2 pin (on the board) like Blynk., you connect LED to that pin,
your code is :

void setup(){
pinMode(2,OUTPUT);
}
void loop(){
digitalWrite(2,HIGH);
delay(1000);
digitalWrite(2,LOW);
delay(1000);
}
The note is : pin map of ESP32 ...

im progamming ESP32 with arduino IDE. I choose ESP32 because It has big RAM and ROM, super Fast clock.
But,Why esp32' RAM is smaller than i though (500k) ?. Just 299912 bytes RAM . hummmm. :( :(
I used 130000 byte for a BIG array. i think my skecth will around 170000 bytes. (It's free about 120000 ...