ESP32 SPI connection ADXL345

[Ivo]

Hello everyone, I’ve been trying to set up a connection via SPI with an esp32 board and an ADXL345 just like explained in a section of this blog. Although the I2C connection works just fine, the code for the SPI does not seem to be working. Below I attach an image of my particular esp32 board, whose SPI pins I believe to be exactly the same as the ones used in the blog post. I also send the code I’m using. I have made some minor modifications because the original one would not even print anything in the serial monitor. At the moment it shows something, but the accelerations in all axis are 0, so clearly there is a problem since I know for a fact that the accelerometer is working just fine with I2C. I would appreciate any help I can get on this topic because I really need to use SPI on my work due to the fact that I2C is not fast nor reliable enough. Thanks in advance!
Link to the example blog post I’m using: http://mischianti.org/gy-291-adxl345-i2c-spi-accelerometer-with-interrupt-for-esp32-esp8266-stm32-and-arduino/?unapproved=15699&moderation-hash=41460f36fc37063897f16c7549c6b516#comment-15699

`#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>

#define SCK 18
#define MISO 19
#define MOSI 23
#define SS 5

Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(18, 19, 23, 5, 12345);
//Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(SCK, MISO, MOSI, SS, 12345);

void setup(void)
{
Serial.begin(9600);
delay(1000);
Serial.println(“Accelerometer Test”); Serial.println(“”);
accel.begin();

/* Initialise the sensor */
if(!accel.begin())
{
/* There was a problem detecting the ADXL345 … check your connections */
Serial.println(“Ooops, no ADXL345 detected … Check your wiring!”);
Serial.println(“What is happening?”);
delay(1000);
while(1);
}

/* Set the range to whatever is appropriate for your project */
accel.setRange(ADXL345_RANGE_16_G);
// accel.setRange(ADXL345_RANGE_8_G);
// accel.setRange(ADXL345_RANGE_4_G);
// accel.setRange(ADXL345_RANGE_2_G);

/* Display some basic information on this sensor */
displaySensorDetails();

/* Display additional settings (outside the scope of sensor_t) */
displayDataRate();
displayRange();
Serial.println(“”);
}

void loop(void)
{
/* Get a new sensor event */
sensors_event_t event;
accel.getEvent(&event);

/* Display the results (acceleration is measured in m/s^2) */
Serial.print(“X: “); Serial.print(event.acceleration.x); Serial.print(” “);
Serial.print(“Y: “); Serial.print(event.acceleration.y); Serial.print(” “);
Serial.print(“Z: “); Serial.print(event.acceleration.z); Serial.print(” “);Serial.println(“m/s^2 “);
delay(500);
}

void displaySensorDetails(void)
{
sensor_t sensor;
accel.getSensor(&sensor);
Serial.println(“————————————“);
Serial.print (“Sensor: “); Serial.println(sensor.name);
Serial.print (“Driver Ver: “); Serial.println(sensor.version);
Serial.print (“Unique ID: “); Serial.println(sensor.sensor_id);
Serial.print (“Max Value: “); Serial.print(sensor.max_value); Serial.println(” m/s^2″);
Serial.print (“Min Value: “); Serial.print(sensor.min_value); Serial.println(” m/s^2″);
Serial.print (“Resolution: “); Serial.print(sensor.resolution); Serial.println(” m/s^2″);
Serial.println(“————————————“);
Serial.println(“”);
delay(500);
}

void displayDataRate(void)
{
Serial.print (“Data Rate: “);

switch(accel.getDataRate())
{
case ADXL345_DATARATE_3200_HZ:
Serial.print (“3200 “);
break;
case ADXL345_DATARATE_1600_HZ:
Serial.print (“1600 “);
break;
case ADXL345_DATARATE_800_HZ:
Serial.print (“800 “);
break;
case ADXL345_DATARATE_400_HZ:
Serial.print (“400 “);
break;
case ADXL345_DATARATE_200_HZ:
Serial.print (“200 “);
break;
case ADXL345_DATARATE_100_HZ:
Serial.print (“100 “);
break;
case ADXL345_DATARATE_50_HZ:
Serial.print (“50 “);
break;
case ADXL345_DATARATE_25_HZ:
Serial.print (“25 “);
break;
case ADXL345_DATARATE_12_5_HZ:
Serial.print (“12.5 “);
break;
case ADXL345_DATARATE_6_25HZ:
Serial.print (“6.25 “);
break;
case ADXL345_DATARATE_3_13_HZ:
Serial.print (“3.13 “);
break;
case ADXL345_DATARATE_1_56_HZ:
Serial.print (“1.56 “);
break;
case ADXL345_DATARATE_0_78_HZ:
Serial.print (“0.78 “);
break;
case ADXL345_DATARATE_0_39_HZ:
Serial.print (“0.39 “);
break;
case ADXL345_DATARATE_0_20_HZ:
Serial.print (“0.20 “);
break;
case ADXL345_DATARATE_0_10_HZ:
Serial.print (“0.10 “);
break;
default:
Serial.print (“???? “);
break;
}
Serial.println(” Hz”);
}

void displayRange(void)
{
Serial.print (“Range: +/- “);

switch(accel.getRange())
{
case ADXL345_RANGE_16_G:
Serial.print (“16 “);
break;
case ADXL345_RANGE_8_G:
Serial.print (“8 “);
break;
case ADXL345_RANGE_4_G:
Serial.print (“4 “);
break;
case ADXL345_RANGE_2_G:
Serial.print (“2 “);
break;
default:
Serial.print (“?? “);
break;
}
Serial.println(” g”);
}
Wiring:
esp32 GND – ADXL345 GND
esp32 3.3V – ADXL345 VCC
esp32 G5 – ADXL345 CS
esp32 G19 – ADXL345 SDO
esp32 G21- ADXL345 SDA
esp32 G18 – ADXL345 SCL

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