ESP32 Forum

Posted: **Wed Sep 08, 2021 10:39 am**

I'm trying to use custom pins for SPI (the multiple SPI example). But getting the `Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled.` error. I have decoded the backtrace. Any help would be appreciated.

My sketch

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/* The ESP32 has four SPi buses, however as of right now only two of
 * them are available to use, HSPI and VSPI. Simply using the SPI API 
 * as illustrated in Arduino examples will use VSPI, leaving HSPI unused.
 * 
 * However if we simply intialise two instance of the SPI class for both
 * of these buses both can be used. However when just using these the Arduino
 * way only will actually be outputting at a time.
 * 
 * Logic analyser capture is in the same folder as this example as
 * "multiple_bus_output.png"
 * 
 * created 30/04/2018 by Alistair Symonds
 */
#include <SPI.h>
 
// Define ALTERNATE_PINS to use non-standard GPIO pins for SPI bus
 
#ifdef ALTERNATE_PINS
  #define VSPI_MISO   2
  #define VSPI_MOSI   4
  #define VSPI_SCLK   0
  #define VSPI_SS     33
 
  #define HSPI_MISO   26
  #define HSPI_MOSI   27
  #define HSPI_SCLK   25
  #define HSPI_SS     32
#else
  #define VSPI_MISO   MISO
  #define VSPI_MOSI   MOSI
  #define VSPI_SCLK   SCK
  #define VSPI_SS     SS
 
  #define HSPI_MISO   12
  #define HSPI_MOSI   13
  #define HSPI_SCLK   14
  #define HSPI_SS     15
#endif
 
static const int spiClk = 1000000; // 1 MHz
 
//uninitalised pointers to SPI objects
SPIClass * vspi = NULL;
SPIClass * hspi = NULL;
 
void setup() {
  //initialise two instances of the SPIClass attached to VSPI and HSPI respectively
  vspi = new SPIClass(VSPI);
  hspi = new SPIClass(HSPI);
  
  //clock miso mosi ss
 
#ifndef ALTERNATE_PINS
  //initialise vspi with default pins
  //SCLK = 18, MISO = 19, MOSI = 23, SS = 5
  vspi->begin();
#else
  //alternatively route through GPIO pins of your choice
  vspi->begin(VSPI_SCLK, VSPI_MISO, VSPI_MOSI, VSPI_SS); //SCLK, MISO, MOSI, SS
#endif
 
#ifndef ALTERNATE_PINS
  //initialise hspi with default pins
  //SCLK = 14, MISO = 12, MOSI = 13, SS = 15
  hspi->begin();
#else
  //alternatively route through GPIO pins
  hspi->begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_SS); //SCLK, MISO, MOSI, SS
#endif
 
  //set up slave select pins as outputs as the Arduino API
  //doesn't handle automatically pulling SS low
  pinMode(VSPI_SS, OUTPUT); //VSPI SS
  pinMode(HSPI_SS, OUTPUT); //HSPI SS
 
}
 
// the loop function runs over and over again until power down or reset
void loop() {
  //use the SPI buses
  vspiCommand();
  hspiCommand();
  delay(100);
}
 
void vspiCommand() {
  byte data = 0b01010101; // junk data to illustrate usage
 
  //use it as you would the regular arduino SPI API
  vspi->beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
  digitalWrite(VSPI_SS, LOW); //pull SS slow to prep other end for transfer
  vspi->transfer(data);  
  digitalWrite(VSPI_SS, HIGH); //pull ss high to signify end of data transfer
  vspi->endTransaction();
}
 
void hspiCommand() {
  byte stuff = 0b11001100;
  
  hspi->beginTransaction(SPISettings(spiClk, MSBFIRST, SPI_MODE0));
  digitalWrite(HSPI_SS, LOW);
  hspi->transfer(stuff);
  digitalWrite(HSPI_SS, HIGH);
  hspi->endTransaction();
}

GeSHi © Codebox Plus Extension

Output from serial monitor

Code: Select all

rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 271414342, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1044
load:0x40078000,len:10124
load:0x40080400,len:5856
entry 0x400806a8
Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.
Core 1 register dump:
PC      : 0x40080f31  PS      : 0x00060730  A0      : 0x800d0f3d  A1      : 0x3ffb1f30
A2      : 0x0000000e  A3      : 0x00000002  A4      : 0x3ffb8364  A5      : 0x00000001
A6      : 0x00000000  A7      : 0x00000004  A8      : 0x3f400674  A9      : 0xaaaaaaaa
A10     : 0xaaaaaaaa  A11     : 0x00000030  A12     : 0x3ffb82cc  A13     : 0x00000000
A14     : 0x00000000  A15     : 0x00000000  SAR     : 0x00000009  EXCCAUSE: 0x0000001c
EXCVADDR: 0xaaaaaaaa  LBEG    : 0x400d1258  LEND    : 0x400d1265  LCOUNT  : 0x00000000

ELF file SHA256: 0000000000000000

Backtrace: 0x40080f31:0x3ffb1f30 0x400d0f3a:0x3ffb1f50 0x400d0db2:0x3ffb1f70 0x400d0c2b:0x3ffb1f90 0x400d190a:0x3ffb1fb0 0x40085fa5:0x3ffb1fd0

Rebooting...
ets Jul 29 2019 12:21:46

The decoded backtrace

Code: Select all

0x40080f31: __pinMode at C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\cores\esp32\esp32-hal-gpio.c line 115
0x400d0f3a: spiAttachSCK at C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\cores\esp32\esp32-hal-spi.c line 87
0x400d0db2: SPIClass::begin(signed char, signed char, signed char, signed char) at C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\libraries\SPI\src\SPI.cpp line 57
0x400d0c2b: setup() at C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\libraries\SPI\examples\SPI_Multiple_Buses/SPI_Multiple_Buses.ino line 67
0x400d190a: loopTask(void*) at C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\cores\esp32\main.cpp line 32
0x40085fa5: vPortTaskWrapper at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/port.c line 143

Posted: **Thu Sep 09, 2021 1:35 am**

From the pico-v3 datasheet:

None of the embedded flash data pins are connected externally on ESP32-PICO-V3. These are connected internally to GPIO16, GPIO17, GPIO18, and GPIO23.

MOSI on Arduino is defined to 23, making the example try to reconfigure a pin the SoC needs for flash access. Suggest you change that to something else.

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