Interface an SPI sensor with adafruit QT PY ESP32-C3

Projects Networking, Protocols, and Devices
1

I have interfaced MAX30001 which a SPI sensor with arduino UNO and ardduino R4 minima. The arduino code is working as expected. But when used with adafruit QT PY ESP32-C3, the sensor is not initializing. So I tried using the HSPI class but that is also not working

#include <SPI.h>
#include "max30001.h"

#define HSPI_MISO 8
#define HSPI_MOSI 7
#define HSPI_SCLK 10
#define HSPI_CS   20
#define MAX30001_SPI_SPEED 1000000

SPIClass * hspi = NULL;

MAX30001 max30001(HSPI_CS);

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

  SPI.begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_CS);

  /*hspi = new SPIClass(HSPI);
  hspi->begin(HSPI_SCLK, HSPI_MISO, HSPI_MOSI, HSPI_CS); //SCLK, MISO, MOSI, SS
  pinMode(HSPI_CS, OUTPUT); //HSPI SS*/

  bool ret = max30001.max30001ReadInfo();
  if (ret)
  {
    Serial.println("MAX 30001 read ID Success");
  }
  else
  {
    while (!ret)
    {
      // stay here untill the issue is fixed.
      ret = max30001.max30001ReadInfo();
      Serial.println("Failed to read ID, please make sure all the pins are connected");
      delay(5000);
    }
  }

  Serial.println("Initialising the chip ...");
}

void loop() 
{
}

void max30001RegWrite(unsigned char WRITE_ADDRESS, unsigned long data)
{
    // Combine the register address and the command into one byte:
    byte dataToSend = (WRITE_ADDRESS << 1) | WREG;

    SPI.beginTransaction(SPISettings(MAX30001_SPI_SPEED, MSBFIRST, SPI_MODE0));

    digitalWrite(HSPI_CS   , LOW);

    delay(2);
    SPI.transfer(dataToSend);
    SPI.transfer(data >> 16);
    SPI.transfer(data >> 8);
    SPI.transfer(data);
    delay(2);

    digitalWrite(HSPI_CS   , HIGH);

    SPI.endTransaction();
}

void max30001RegRead(uint8_t Reg_address, uint8_t *buff)
{
    uint8_t spiTxBuff;

    SPI.beginTransaction(SPISettings(MAX30001_SPI_SPEED, MSBFIRST, SPI_MODE0));

    digitalWrite(_cs_pin, LOW);

    spiTxBuff = (Reg_address << 1) | RREG;
    SPI.transfer(spiTxBuff); // Send register location

    for (int i = 0; i < 3; i++)
    {
        buff[i] = SPI.transfer(0xff);
    }

    digitalWrite(_cs_pin, HIGH);

    SPI.endTransaction();
}

bool max30001ReadInfo(void)
{
    uint8_t readBuff[4];

    _max30001RegRead(INFO, readBuff);

    if ((readBuff[0] & 0xf0) == 0x50)
    {
        Serial.print("MAX30001 Detected. Rev ID:  ");
        Serial.println((readBuff[0] & 0xf0));

        return true;
    }
    else
    {

        Serial.println("MAX30001 read info error\n");
        return false;
    }

    return false;
}
2

Are you using the following ESP32-C3 Dev Board?

image
image225×225 27.6 KB

3

adafruit QT PY ESP32-C3

4

it looks similar

5

try running esp32-spi-communication which prints the default SPI pins
on the ESP32-C3-MINI-1 and ESP32-C3 supermini using Tools>Board ESP32C3 Dev Module it displays

MOSI: 6
MISO: 5
SCK: 4
SS: 7

when interfacing a 1_8_inch_ST7735_TFT display I used the default MOSI, MISO, and SCK pins and also defined

 #define TFT_CS         7
  #define TFT_RST        9 
  #define TFT_DC         8

I have used HSPI with ESP32 but not attempted it with the ESP32C3

6

Please, post the picture of your ESP32-C3 Board.

7

IMG_20250131_174600120
IMG_20250131_1746001201920×2550 175 KB

IMG_20250131_174553459
IMG_20250131_1745534591920×2550 165 KB

8

just noted you are using GPIO20 which on the ESP32C3 GPIO20 is U0RXD which with GPIO21 U0TXD are used for Serial programming/debugging
if you are using Serial IO doubt if you can also use it for HSPI_CS

9

Even though I have wired the CS pin of the sensor to pin 20 of adafruit QT PY, while printing the default SPI pins its showing

MOSI:  7
MISO:  8
SCK:  10
SS:  6

AlsoI have defined #define HSPI_CS 20

10

Capture
Capture1314×600 78.8 KB

This is the pin configuration of QT PY ESP32-C3. In that case, let me try with 0,1,3,4 and 5

11

Thanks for the pictures. It is indeed similar to ESP32-C3 of post #2. I am investigating the operation of the SPI Port.

12

MOSI, MISO and SCK look OK try changing HSPI_CS 20 to the default

#define HSPI_CS 6
13

Changing the CS pin to the default pin worked!! Well that is finally resolved..Thank you!!

14

But can I remap the CS pin to 20 instead of the default pin 6?

15

I tried it this way, changed the configuration in the espressif folder.

C:\Users\user\Documents\Arduino\hardware\espressif\esp32\variants\adafruit_qtpy_esp32c3

// Map SPI port to 'new' pins 
#define PIN_SPI_SS    (20)
#define PIN_SPI_MOSI  (7)
#define PIN_SPI_MISO  (8)
#define PIN_SPI_SCK   (10)

static const uint8_t SS = PIN_SPI_SS;
static const uint8_t MOSI = PIN_SPI_MOSI;
static const uint8_t MISO = PIN_SPI_MISO;
static const uint8_t SCK = PIN_SPI_SCK;

But when printing in IDE, its still showing as pin6(default pin) instead of 20.

16

you can remap the SPI pins but ESP32C3 GPIO20 is U0RXD is already used for Serial RX so I doubt if you can use it for CS - you can try! why not just use the default pin 6?

17

I am using only SPI..Correct me if I am wrong, for Serial printing U0RXD is needed. I am trying to mount the sensor on the QT PY, for this purpose CS pin needs to 20.

18

I added these lines to the code and its working

pinMode(CS_PIN, OUTPUT);
digitalWrite(CS_PIN, HIGH);

I removed the changes from the C:\Users\user\Documents\Arduino\hardware\espressif\esp32\variants\adafruit_qtpy_esp32c3

19

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