Serial comm UART1 works on Arduino but makes ESP32 continuously reboot

Question

This comm sketch simply read incoming bytes from the UART 1 where a device is attached. It works normally on a real Arduino device. But on ESP32, it makes it continuously reboot with the following messages:

([UPDATE] Note that there is no reboot on ESP32 is I use Serial2 instead of Serial1)

9:13:19.676 -> ets Jun 8 2016 00:22:57
19:13:19.676 -> 
19:13:19.676 -> rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
19:13:19.676 -> configsip: 0, SPIWP:0xee
19:13:19.676 -> clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
19:13:19.676 -> mode:DIO, clock div:1
19:13:19.676 -> load:0x3fff0018,len:4
19:13:19.676 -> load:0x3fff001c,len:1216
19:13:19.714 -> ho 0 tail 12 room 4
19:13:19.714 -> load:0x40078000,len:10944
19:13:19.714 -> load:0x40080400,len:6388
19:13:19.714 -> entry 0x400806b4
19:13:19.786 -> Yo! from serial UART 18/19
19:13:19.786 -> SbmDi⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮@D@⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮
@%cGuru Meditation Error: Core 1 panic'ed (IllegalInstruction). Exception was unhandled.
19:13:19.823 -> Memory dump at 0x400e90f4: ffffffff ffffffff ffffffff
19:13:19.823 -> Core 1 register dump:
19:13:19.823 -> PC : 0x400e90f8 PS : 0x00060530 A0 : 0x800d1529 A1 : 0x3ffb1f80 
19:13:19.823 -> A2 : 0x3ffbfe88 A3 : 0x3ffbfe6c A4 : 0x0001c200 A5 : 0x0800001c 
19:13:19.823 -> A6 : 0x00004e20 A7 : 0x00000000 A8 : 0x800d0c4f A9 : 0x3ffb1f60 
19:13:19.857 -> A10 : 0x3ffbfe6c A11 : 0x3f40013b A12 : 0x0800001c A13 : 0x00000009 
19:13:19.857 -> A14 : 0x00000009 A15 : 0x00000000 SAR : 0x00000016 EXCCAUSE: 0x00000000 
19:13:19.857 -> EXCVADDR: 0x00000000 LBEG : 0x400014fd LEND : 0x4000150d LCOUNT : 0xffffffbd 
19:13:19.857 -> 
19:13:19.857 -> ELF file SHA256: 0000000000000000
19:13:19.857 -> 
19:13:19.857 -> Backtrace: 0x400e90f8:0x3ffb1f80 0x400d1526:0x3ffb1fb0 0x400860ed:0x3ffb1fd0
19:13:19.891 -> 
19:13:19.891 -> Rebooting...

Here's my code:

#include <Arduino.h>
#define SbmDisplaySerial Serial1
void setup() {
 Serial.begin(115200);
 //Serial.setDebugOutput(true);
 Serial.println("Yo v0.0.1! from serial UART 18/19");
 SbmDisplaySerial.begin(9600, SERIAL_8N1);//, 16, 17);
 Serial.print("SbmDisplaySerial is ");
 Serial.println(SbmDisplaySerial);
}
int _loop = 1;
void loop() {
 // put your main code here, to run repeatedly:
 Serial.print("Loop #"); Serial.println(_loop++);
 delay(1000);
 if (!SbmDisplaySerial.available()) {
 delay(2000);
 Serial.println("No byte avail from the UART, looping...");
 return;
 }
 int b = 0;
 Serial.print("Synching with message limit (waiting for 0xA5 (165) header byte): ");
 int i=0;
 do {
 delay(10);
 b = SbmDisplaySerial.read();
 Serial.print(b); 
 Serial.print(" ");
 if (i%128==0) Serial.println(); 
 i++;
 }
 while(b!=0xa5);
 Serial.println("Ok, packet started!");
 Serial.print("Received bytes: ");
 Serial.print(b);
 Serial.print(" ");
 int soc = 0;
 int voltage = 0;
 int current = 0;
 int capacity = 0;
 for(int i=1; i<16; i++) { 
 b = SbmDisplaySerial.read()&0xff;
 Serial.print(b);
 Serial.print(" ");
 switch(i) {
 case 0: Serial.print("Header byte 0xA5"); 
 voltage = 0;
 current = 0;
 capacity = 0;
 break;
 case 1: soc = b; Serial.print("(SoC: "); Serial.print(soc); Serial.print("%) "); break;
 
 case 2: voltage = b<<8; break;
 case 3: voltage |= b; Serial.print("("); Serial.print(float(voltage)*0.01); Serial.print("V) "); break;
 
 case 4: capacity = b<<24; break;
 case 5: capacity = b<<16; break;
 case 6: capacity = b<<8; break;
 case 7: capacity |= b; Serial.print("("); Serial.print(float(capacity)*0.001); Serial.print("A.h) "); break;
 
 case 8: current = b<<24; break;
 case 9: current = b<<16; break;
 case 10: current = b<<8; break;
 case 11: current |= b; Serial.print("("); Serial.print(float(current)*0.001); Serial.print("A) "); break;
 
 //case 12: current = b<<8; break;
 //case 13: current = b<<8; break;
 //case 10: current |= b; Serial.print("(TOA: "); Serial.print(float(current)*0.001); Serial.print("Seconds) "); break;
 }
 
 if (!SbmDisplaySerial.available()){
 delay(2000);
 Serial.print(" No more byte prior reaching 16 bytes, looping...");
 break;
 }
 }
 Serial.println("Waiting for next packet");
 delay(10000);
 
}

[UPDATE] When ran on Arduino, I get typical logs as follows:

11:20:18.217 -> Yo v0.0.1! from serial UART 18/19
11:20:18.217 -> SbmDisplaySerial is 1
11:20:18.217 -> Loop #1
11:20:19.204 -> Synching with message limit (waiting for 0xA5 (165) header byte): 0 
11:20:19.204 -> 0 0 0 0 165 Ok, packet started!
11:20:19.275 -> Received bytes: 165 28 (SoC: 28%) 4 251 (12.75V) 0 0 54 248 (14.07A.h) 255 255 0 0 (0.00A) 0 0 0 0 Waiting for next packet
11:20:29.263 -> Loop #2
11:20:30.266 -> Synching with message limit (waiting for 0xA5 (165) header byte): 0 
11:20:30.266 -> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 165 Ok, packet started!
11:20:30.508 -> Received bytes: 165 28 (SoC: 28%) 4 251 (12.75V) 0 0 182 0 (46.59A.h) 0 0 0 0 (0.00A) 0 0 0 0 Waiting for next packet

• StarCat: Serial.println(SbmDisplaySerial); how is that supposed to work?
• Stéphane de Luca: You simply read: "10:46:23.574 -> SbmDisplaySerial is 1" but you can ignoire, it's pure logging message.
• StarCat: The problem is that SbmDisplaySerial (or any Arduino Serial object) is not equal to "1", but an object with all kinds of properties that you can't simply "print". I don't know why the Arduino (AVR) allows this, but the Serial implementation of the ESP32 might not handle this gracefully. Why don't you try leaving this Serial.println() statement out and see if it makes a difference?
• StarCat: FYI, I've tried your code on my own ESP32 and it does not crash. What Arduino IDE and ESP32 Core version are you using?
• Stéphane de Luca: @StarCat This is used to know the state of the connection (see arduino.cc/reference/en/language/functions/communication/serial/…). And anyway, If I remove it it makes no change to the game.

Answer 1

Here is what I've ended up with: I dropped Serial1 as I did not find anyway to make it run and I switched to Serial2, where everything works as expected.

Answer 2

#define SER1_RX 35
#define SER1_TX 32
void setup()
{ 
 Serial.begin(115200); // 
 Serial.setDebugOutput(1);
 // For Serial1, be sure to set the communication port.
 Serial1.begin(115200, SER1_RX, SER1_TX); // set the communication port
}