Cannot use SPI or set custom pins for SPI on esp32

Hello.

I'm using an esp32 (esp32 pico-mini-02, to be exact). When I try to use the SPI it results in Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled. Using the esp32exceptiondecoder, I was some what able to narrow down the problem but am unable to solve it.

If anyone has any idea what is going on, please share you thoughts.

Thank you.

The full error message

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

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

The example sketch



/* 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

#if CONFIG_IDF_TARGET_ESP32S2
#define VSPI FSPI
#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();
}

I've tried various combination of pins, nothing seems to work.

You are using V1.0.5 of the ESP32 core and 2.0.0 is available. Maybe an update would help. Go to Tools->Board:->Boards Manager... and select Type "Updatable".

If you don't want to update, open the file C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\cores\esp32\esp32-hal-gpio.c and see what pinMode() is doing on Line 115.

If that doesn't sort it out, open the file C:\Users\newto\OneDrive\Documents\ArduinoData\packages\esp32\hardware\esp32\1.0.5\cores\esp32\esp32-hal-spi.c and see which pin it is calling pinMode() for on line 87. That seems to be causing the crash. Maybe the pin you have chosen is invalid in some way.

@johnwasser Tried many versions, same result.

I'll look into the other solution.

Use a non-portB pin for SPI.

The way you initialize the SPI ports is quite strange.

@Idahowalker I've tried that, doesn't work.

Currently I'm looking into the second suggestion by @johnwasser

I actually do not use the Arduino SPI API, its slow and leaves off a lot of ESP32 SPI features.
Below is a code I use as my base model for ESP32 SPI applications. The code bypasses the Arduino ESP32 core and talks directly to the SPI module.

.h file

#include <driver/spi_master.h>
#include "sdkconfig.h"
#include "esp_system.h" //This inclusion configures the peripherals in the ESP system.
////////////////////////////////////
//
//#define MAGTYPE  true
//#define XGTYPE   false
//////////////////////////
///////////////////////////
//
////////////////////////////
 uint8_t GetLowBits();
 int8_t GetHighBits();
 int fReadSPIdata16bits( spi_device_handle_t &h, int address );
 int fWriteSPIdata8bits( spi_device_handle_t &h, int address, int sendData );
 int fInitializeSPI_Devices( spi_device_handle_t &h, int csPin);
// spi_device_handle_t fInitializeSPI_Devices( int csPin);
int fInitializeSPI_Channel( int spiCLK, int spiMOSI, int spiMISO, spi_host_device_t SPI_Host, bool EnableDMA);

my .ccp file

#include "ESP32_SPI_API.h"
/////////////////////////////
///////////////////////////
uint8_t txData[2] = { };
uint8_t rxData[25] = { };
uint8_t low;
int8_t high;
//////
//////////////////////////////////
uint8_t GetLowBits()
{
  return low;
}
int8_t GetHighBits()
{
  return high;
}
////////////////////////////////////////
int fInitializeSPI_Channel( int spiCLK, int spiMOSI, int spiMISO, spi_host_device_t SPI_Host, bool EnableDMA)
{
  esp_err_t intError;
  spi_bus_config_t bus_config = { };
  bus_config.sclk_io_num = spiCLK; // CLK
  bus_config.mosi_io_num = spiMOSI; // MOSI
  bus_config.miso_io_num = spiMISO; // MISO
  bus_config.quadwp_io_num = -1; // Not used
  bus_config.quadhd_io_num = -1; // Not used
  intError = spi_bus_initialize( HSPI_HOST, &bus_config, EnableDMA) ;
  return intError;
}
//////
int fInitializeSPI_Devices( spi_device_handle_t &h, int csPin)
{
  esp_err_t intError;
  spi_device_interface_config_t dev_config = { };  // initializes all field to 0
  dev_config.address_bits     = 0;
  dev_config.command_bits     = 0;
  dev_config.dummy_bits       = 0;
  dev_config.mode             = 3 ;
  dev_config.duty_cycle_pos   = 0;
  dev_config.cs_ena_posttrans = 0;
  dev_config.cs_ena_pretrans  = 0;
  dev_config.clock_speed_hz   = 5000000;
  dev_config.spics_io_num     = csPin;
  dev_config.flags            = 0;
  dev_config.queue_size       = 1;
  dev_config.pre_cb           = NULL;
  dev_config.post_cb          = NULL;
  spi_bus_add_device(HSPI_HOST, &dev_config, &h);
  // return intError;
  // return h;
} // void fInitializeSPI_Devices()
///////////////////////////////////////////////////////////////
int fReadSPIdata16bits( spi_device_handle_t &h, int _address )
{
  uint8_t address = _address;
    esp_err_t intError = 0;
    low=0; high=0;
    spi_transaction_t trans_desc;
    trans_desc = { };
    trans_desc.addr =  0;
    trans_desc.cmd = 0;
    trans_desc.flags = 0;
    trans_desc.length = (8 * 3); // total data bits
    trans_desc.tx_buffer = txData;
    trans_desc.rxlength = 8 * 2 ; // Number of bits NOT number of bytes
    trans_desc.rx_buffer = rxData;
    txData[0] = address | 0x80;
    intError = spi_device_transmit( h, &trans_desc);
    low = rxData[0]; high = rxData[1];
  //  if ( intError != 0 )
  //  {
  //    Serial.print( " WHO I am LSM9DS1. Transmitting error = ");
  //    Serial.println ( esp_err_to_name(intError) );
  //  }
  return intError;
} // void fSendSPI( uint8_t count, uint8_t address, uint8_t DataToSend)
////
int fWriteSPIdata8bits( spi_device_handle_t &h, int _address, int _sendData )
{
  uint8_t address =  _address;
  uint8_t sendData = _sendData;
  esp_err_t intError;
  spi_transaction_t trans_desc;
  trans_desc = { };
  trans_desc.addr =  0;
  trans_desc.cmd = 0;
  trans_desc.flags = 0;
  trans_desc.length = (8 * 2); // total data bits
  trans_desc.tx_buffer = txData;
  trans_desc.rxlength = 0 ; // Number of bits NOT number of bytes
  trans_desc.rx_buffer = NULL;
  txData[0] = address  & 0x7F;
  txData[1] = sendData;
  intError = spi_device_transmit( h, &trans_desc);
  return intError;
//  //  if ( intError != 0 )
//  //  {
//  //    Serial.print( " LSM9DS1_REGISTER_CTRL_REG6_XL. Transmitting error = ");
//  //    Serial.println ( esp_err_to_name(intError) );
//  //  }
} // void fWriteSPIdata8bits(  spi_device_handle_t &h, uint8_t address, uint8_t sendData )
//

ESP32 SPI API

Even using the SPI API you must not use GPIO pins on portB, like GPIO_NUM_33 and up for cs pins