7 years, 4 months ago.

How to read data through SPI on Nucleo-F411RE board

Hello,

Basically, I want to interface ADS1292R with the Nucleo-F411RE board. I want to test reading and writing operation of this IC. So I wrote some code but it's not working. Actually, I have doubt on SPI configuration. Testing Done: 1) I am not able to see any MOSI, SCLK signal data on DSO at the time of write operation. 2) I didn't see any MISO data on DSO at the time of reading operation but I saw SCLK. Can someone help me how to do that?

Please find the source code.

    #include "mbed.h"
    #include <SPI.h>
    // Register Read Commands
    #define  RREG    0x20;      //Read n nnnn registers starting at address r rrrr
                                    //first byte 001r rrrr (2xh)(2) - second byte 000n nnnn(2)
    #define WREG    0x40;       //Write n nnnn registers starting at address r rrrr
                                    //first byte 010r rrrr (2xh)(2) - second byte 000n nnnn(2)                              
    #define START       0x08        //Start/restart (synchronize) conversions
    #define STOP        0x0A        //Stop conversion
    #define RDATAC      0x10        //Enable Read Data Continuous mode. 
    
    //This mode is the default mode at power-up.
    #define SDATAC      0x11        //Stop Read Data Continuously mode
    #define RDATA       0x12        //Read data by command; supports multiple read back.
    
    #define HIGH (1)
    #define LOW (0)
    #define PIN_PWDN (1)
    #define PIN_START (2)
    #define PIN_DRDY (3)
    #define PIN_CS (4)
    //register address
    #define ADS1292_REG_ID          0x00
    #define ADS1292_REG_CONFIG2     0x02
    
    DigitalOut ADS1292_PWDN_PIN(PB_5);      //pin PD_4 used for power down of the ADS1292
    DigitalOut ADS1292_START_PIN(PB_4);     // pin PD_5 used for Start of the ADS1292 
    DigitalOut ADS1292_CS_PIN(PA_8);        //pin PD_7 used for Chip select of the ADS1292
    DigitalIn ADS1292_DRDY_PIN(PB_10);      //pin PD_6 used for Data ready input of the ADS1292
    SPI device(SPI_MOSI, SPI_MISO, SPI_SCK);
    Serial pc(SERIAL_TX, SERIAL_RX);
     
    void digitalWrite(int pin_in, int status_in){
        switch(pin_in){
            case PIN_PWDN:
                ADS1292_PWDN_PIN = status_in;
                break;
            case PIN_START:
                ADS1292_START_PIN = status_in;
                break;
            case PIN_CS:
                ADS1292_CS_PIN = status_in;
                break;    
            default :
                break;
        }}
     
     
    void Reg_Write (unsigned char READ_WRITE_ADDRESS, unsigned char DATA)
    {
      pc.printf("In Function Write_Data()\n\r");
      switch (READ_WRITE_ADDRESS)
      {
        case 1: DATA = DATA & 0x87; break;
        case 2: DATA = DATA & 0xFB; DATA |= 0x80; break;
        default: break;      
      }
      // now combine the register address and the command into one byte:
      unsigned char dataToSend = READ_WRITE_ADDRESS | WREG;
      digitalWrite(PIN_CS, LOW);
      wait_us(2);
      digitalWrite(PIN_CS, HIGH);
      wait_us(2);
      digitalWrite(PIN_CS, LOW); // take the chip select low to select the device:
      wait_us(2);
      device.write(dataToSend); //Send register location
      device.write(0x00);       //number of register to wr
      device.write(DATA);       //Send value to record into register
      wait_us(2);
      digitalWrite(PIN_CS, HIGH); // take the chip select high to de-select:
    }
     
    void Reg_Read (unsigned char READ_WRITE_ADDRESS){
        unsigned char dataToSend = READ_WRITE_ADDRESS | RREG;
        digitalWrite(PIN_CS, LOW);
        wait_us(2);
        digitalWrite(PIN_CS, HIGH);
        wait_us(2);
        digitalWrite(PIN_CS, LOW);						// take the chip select low to select the device:
        wait_us(2);
        device.write(dataToSend); 						//Send register location
        device.write(0x00);       						//number of register to wr
        unsigned char Value = device.write(0x00);       //Send value to record into register
        pc.printf("Data read : %x\n\r",Value);
        wait_us(2);
        digitalWrite(PIN_CS, HIGH); 					// take the chip select high to de-select:
    }
    void SPI_Init(void){
        pc.printf("In Function SPI_Init()\n\r");
        digitalWrite(PIN_CS, HIGH);
        device.format(8,1);
        device.frequency(1000000);
        digitalWrite(PIN_CS, LOW);
    }
    int main() {
        int i = 0;
        pc.baud(115200);
        pc.printf("In Function main()\n\r");
        SPI_Init();
        wait(5);
        while(1) 
        {
            i++;
            Reg_Write(ADS1292_REG_CONFIG2, 0b11111111);   //Lead-off comp off, test signal disabled 0b10100000
            wait_us(10);
            Reg_Read(ADS1292_REG_CONFIG2);
            if(i == 10)
                while(1);
            wait(5);
        }
    } 

Result: In Function main() In Function SPI_Init() In Function Write_Data() Data read : 0 In Function Write_Data() Data read : 0

Updated my reply

posted by Bill Bellis 20 Jun 2017

1 Answer

7 years, 4 months ago.

Code looks *ok* but I have a couple of questions: Are you using these pins? SPI_MOSI = PA_7, SPI_MISO = PA_6, SPI_SCK = PA_5, SPI_CS = PB_6,

The frequency of the external clock fCLK on the AD1292 does matter. What is it?

Have you tried slower SPI frequencies and increasing the delay time between CS->LOW and CS->HIGH?

Thanks

posted by harsh bhai 18 Jun 2017

I am using SPI_MOSI = PA_7, SPI_MISO = PA_6, SPI_SCK = PA_5 but for SPI_CS = PA_8. So is there any problem to use this pin.

As per my understanding, I am not using external clock frequency. Basically, I am using ready-made hardware which is provided by "ADS1292r breakout".

I didn't try slower SPI frequencies.

Thank you very much for your reply Bill Bellis, Let me know if you have any more questions. Looking forward to the same issue.

posted by harsh bhai 20 Jun 2017