How to drive the LED in ADPD4101 sensor?

Hi,

We are using ADPD4101 sensor which is using I2C interface. I am unable to drive the LED which is present in ADPD4101 sensor.

I have attached my code snippet here. I am looking ahead for your suggestion on ADPD4101 sensor LED drive.

int32_t adpd410x_reg_read(nrf_drv_twi_t const *p_instance, uint16_t address, uint16_t *store_data)
{
	uint32_t ret_code;
	uint8_t buff[] = {0, 0, 0, 0};

        buff[0] = ((address >> 8) & 0x00ff) | 0x80;
        buff[1] = address & 0xff;
        /* No stop bit */
        ret_code = nrf_drv_twi_tx(p_instance, HRM_I2C_ADDRESS, buff, 2, true);
        if(ret_code != NRF_SUCCESS)
           return ret_code;
        ret_code = nrf_drv_twi_rx(p_instance, HRM_I2C_ADDRESS, (buff + 2), 2);
        if(ret_code != NRF_SUCCESS)
           return ret_code;

	*store_data = ((uint16_t)buff[2] << 8) & 0xff00;
	*store_data |= buff[3] & 0xff;

	return NRF_SUCCESS;
}
/**
 * @brief Write device register.
 * @param address - Register address.
 * @param data - New register value.
 * @return NRF_SUCCESS in case of success, FAILURE otherwise.
 */
int32_t adpd410x_reg_write(nrf_drv_twi_t const *p_instance, uint16_t address, uint16_t data)
{
	uint8_t buff[] = {0, 0, 0, 0};

          buff[0] = ((address >> 8) & 0x00ff) | 0x80;
          buff[1] = address & 0xff;
          buff[2] = (data >> 8) & 0x00ff;
          buff[3] = data & 0xff;

        return nrf_drv_twi_tx(p_instance, HRM_I2C_ADDRESS, buff, 4, false);
}

/**
 * @brief Do a software reset.
 * @return NRF_SUCCESS in case of success, FAILURE otherwise.
 */
int32_t adpd410x_reset(nrf_drv_twi_t const *p_instance)
{
	int32_t ret;

	ret = adpd410x_reg_write(p_instance, ADPD410X_REG_SYS_CTL, BITM_SYS_CTL_SW_RESET);
	if(ret != NRF_SUCCESS)
          return ret;
}

uint16_t reg_temp_1, val_1;
void get_ADPD4_chip_ID(nrf_drv_twi_t const *p_instance, uint8_t i2c_line)
{
        int32_t ret_code;
       
	ret_code = adpd410x_reg_read(p_instance, ADPD410X_REG_CHIP_ID, &reg_temp_1);
	if(ret_code != NRF_SUCCESS){ 
          NRF_LOG_INFO("HRM I2C read failure");
          return;
        }
        val_1 = reg_temp_1 & BITM_CHIP_ID;
        if((val_1) == (uint16_t)ADPD410X_CHIP_ID){
            NRF_LOG_INFO("ADPD4101 CHIP-ID read success");
        }
        else{
            NRF_LOG_INFO("ADPD4101 CHIP-ID read failure");   
        }
}

/**
 * @brief Set operation mode.
 * @return NRF_SUCCESS in case of success, FAILURE otherwise.
 */
int32_t adpd410x_set_opmode(nrf_drv_twi_t const *p_instance, uint16_t opmode)
{
	return adpd410x_reg_write(p_instance, ADPD410X_REG_OPMODE, opmode); 
}


/**
 * @brief Set number of active time slots.
 * @param timeslot_no - Last time slot to be enabled.
 * @return NRF_SUCCESS in case of success, FAILURE otherwise.
 */
int32_t adpd410x_set_last_timeslot(nrf_drv_twi_t const *p_instance, enum adpd410x_timeslots timeslot_no)
{
	return adpd410x_reg_write(p_instance, ADPD410X_REG_OPMODE, timeslot_no);
}

/**
 * @brief Set device sampling frequency.
 * @param sampling_freq - New sampling frequency.
 * @return NRF_SUCCESS in case of success, FAILURE otherwise.
 */
int32_t adpd410x_set_sampling_freq(nrf_drv_twi_t const *p_instance, uint32_t sampling_freq)
{
	int32_t ret;
	uint32_t reg_load;
	uint16_t reg_temp;
#if 1

        ret = adpd410x_reg_read(p_instance, ADPD410X_REG_SYS_CTL, &reg_temp);
        if(ret != NRF_SUCCESS)
            return ret;
        if(reg_temp & BITP_SYS_CTL_LFOSC_SEL)
            reg_load = ADPD410X_LOW_FREQ_OSCILLATOR_FREQ1;
        else
            reg_load = ADPD410X_LOW_FREQ_OSCILLATOR_FREQ2;

        reg_load /= sampling_freq;
#endif
        reg_load = ADPD410X_LOW_FREQ_OSCILLATOR_FREQ2;
	ret = adpd410x_reg_write(p_instance, ADPD410X_REG_TS_FREQ, (reg_load & 0xFFFF));
	if(ret != NRF_SUCCESS)
          return ret;
}

int32_t ADPD410x_device_setup(nrf_drv_twi_t const *p_instance, enum adpd410x_timeslots m_timeslot_no, uint8_t i2c_line)
{
        int32_t ret;
        uint16_t data;

        data = 0x4000;                           //Enable Channel 2
	ret = adpd410x_reg_write(p_instance, ADPD410X_REG_TS_CTRL(m_timeslot_no), data);       //0x0100
        if(ret != NRF_SUCCESS)
            return ret;

        if(i2c_line == 1)
        {
            data = 0x1000;                       //IN2 connected to VC1...IN7
            ret = adpd410x_reg_write(p_instance, ADPD410X_REG_INPUTS(m_timeslot_no), data);   //0x0102
            if(ret != NRF_SUCCESS)
                return ret;         
        }
        else
        {
            //m_timeslot_no = 6;                 //Setup inputs 
            data = 0x4043;                       //IN2 connected to VC1...IN4, IN8 connected to VC2
            ret = adpd410x_reg_write(p_instance, ADPD410X_REG_INPUTS(m_timeslot_no), data);   //0x01C2-G slot //0x0102
            if(ret != NRF_SUCCESS)
                return ret;
        }

	data = 0x0E0E;                       //21 mA output current & slot A has been selected 1A, 2A
	ret = adpd410x_reg_write(p_instance, ADPD410X_REG_LED_POW12(m_timeslot_no), data);  //0x0105
        if(ret != NRF_SUCCESS)
            return ret;

        data = 0x0E0E;                       //21 mA output current & slot A has been selected 3A, 4A
	ret = adpd410x_reg_write(p_instance, ADPD410X_REG_LED_POW34(m_timeslot_no), data);  //0x0106
        if(ret != NRF_SUCCESS)
            return ret;

        data = 0xFF0A;                       //Pulse width max & offset max/2
        ret = adpd410x_reg_write(p_instance, ADPD410X_REG_LED_PULSE(m_timeslot_no), data); //0x0109
        if(ret != NRF_SUCCESS)
            return ret;

#if 0
        data = 0x1E00;                       //21 mA output current & slot B has been selected 4B
        ret = adpd410x_reg_write(p_instance, ADPD410X_REG_LED_POW34(m_timeslot_no), data);  //0x0126
        if(ret != NRF_SUCCESS)
            return ret;
#endif
}

int32_t adpd410x_set_clock_freq(nrf_drv_twi_t const *p_instance)
{
      int32_t ret;
      ret = adpd410x_reg_write(p_instance, ADPD410X_REG_SYS_CTL, 0x0002);    //1 Mhz low freq internal oscillator selected
      if(ret != NRF_SUCCESS)
        return ret;
}

void init_ADPD410x(nrf_drv_twi_t const *p_instance)
{
        adpd410x_reset(p_instance);                 //SW reset
        adpd410x_set_opmode(p_instance, BITP_OPMODE_OP_MODE);  //standby mode 
        adpd410x_set_clock_freq(p_instance);        //1 Mhz sampling freq
        //adpd410x_set_sampling_freq(p_instance, SAMPLING_FREQ);   //For 1MHz freq - Sampling rate will be 100Hz   
        adpd410x_set_last_timeslot(p_instance, ADPD410X_TS_A); //Time slot A
}

main()
{

/*Check ADPD4101 sensor */
      get_ADPD4_chip_ID(&m_twi, I2C_LINE0);
      get_ADPD4_chip_ID(&m_twi_1, I2C_LINE1);
      ADPD410x_device_setup(&m_twi, ADPD410X_TS_A, I2C_LINE1);
      nrf_delay_ms(10);
      ADPD410x_device_setup(&m_twi_1, ADPD410X_TS_A, I2C_LINE0);
      nrf_delay_ms(10);
      adpd410x_set_opmode(&m_twi, 0x0001);  // Changing from standby mode to Go mode
      adpd410x_set_opmode(&m_twi_1, 0x0001); // Changing from standby mode to Go mode
      
}

Regards

Sudharsan

Parents
  • +1
    •  Analog Employees 
    on Jun 10, 2021 3:47 PM

    Hi  Sudharsan,

    Have you verified if your register read & write are working?

    With regard to the LED drivers, can you let us know your schematic of the LED(s) and/or PD(s)? The LED drivers of ADPD4101 are current sink and the LED(s) should be supplied with VLED. 

    Regards,

    Glen B. 

  • Hi Glen,

    Thanks for your reply.

    I2C read/write is working fine. LEDs are 1A, 2A, 3A, 4A and 4B

    I have resolved it, as I was not turning on the 1MHz LF OSC

    Its working. I am moving forward to do PPG measurement.

    I'll give you an update on PPG stuffs. I need your support on this sensor's software development, as I am new to this.

    Thanks and Regards

    Sudharsan

  • 0
    •  Analog Employees 
    on Jun 21, 2021 3:48 AM in reply to SK377

    Hi Sudharsan,

    Yes, it's watermark level for FIFO. whenever the FIFO reached the watermark level it will trigger the interrupt.

    You need to configure register 0x22 as inverted output (0x0003U). Since your host expecting falling edge to trigger interrupt.

    Change the register value and check.

    Regards,

    Sathishkumar K

  • Hi Sathish,

    I am getting interrupt on both settings in 0x22 register (output inverted and output normal)

    I have configured as a output inverted and tested and also I have tested with output normal.

    I am getting PPG values from FIFO but I still have no clarity on following register settings. Is this register settings are fine to move forward to calculate Raw PPG to HRM ???

    Currently, we are preferring continuous connect mode. No modulation and No ADC offset has been selected. Please refer the below settings and suggest your comments

    1. Selected continuous connect mode 
    
    data = 0x0000, Reg = 0x0108 
    
    2. Gain setting - TIA gain 100k, Vref = 0.88V  //LEDs current setting is 50mA
    
    data = 0x02C1, Reg = 0x0104
    
    3. Skipped the PRECON and Testing with signal data by passing through "TIA + BPF + INT + ADC" and  "TIA + INT + ADC"       
    
    data = 0x00DA or 0x00E6, Reg =  0x0101
    
    4. when data = 0x99 - getting negative values as well  //Chop settings
    
    data = 0x00AA, Reg = 0x010D
    
    5. ADC pulses = 32, Integrator Pulse width data = 3 us , Integrator Offset data = 0x0210 //16.5us

    Regards

    Sudharsan

  • 0
    •  Analog Employees 
    on Jun 22, 2021 4:05 PM in reply to SK377

    Hi Sudharsan,

    Please follow the example below to config your sensor for PPG measurement:

    ################################################################
    ## ADPD4100 Reference Config File, single-ended IN1 only, timeslot A only
    ## Please review config file for your design. This is a generic config file.
    0009 0080 # 32MHz trim - trim your own clock
    000B 02B2 # 1MHz trim - trim your own clock
    000C 0012 # 32kHz trim - trim your own clock
    000D 2710 # 100 Hz
    000F 0006 # enable 1MHz osc
    0020 0004 # in1 connected to vc1 during sleep, everything else floating
    0021 0000 # all inputs single ended, vc1 set to Vdd during sleep
    0022 0003 # gpio0 is output, inverted
    0023 0002 # intx to gpio0
    0014 8000 # fifo thresh interrupt to intx
    0006 00FF # fifo threshold 128 bytes

    ## timeslot A - continuous connect mode

    0100 0000 # Rin = 500, tsA offset = 0, skip subsample
    0101 40DA # path = TIA + BPF + INT + ADC
    0102 0001 # IN1 to channel 1, others disconnected
    0103 5002 # precondition inputs to TIA_Vref, VC1 active state = V_delta
    0104 03C0 # Rf = 200k Rint = 400k
    0105 0017 # 38 mA on LED1A
    0106 0000
    0107 0104 # 4 pulses
    0108 0000 # period set by automatic period of continuous connect mode
    0109 0210 # led width= 2us led offset=16 us
    010A 0003 # integrator width=3 us
    010B 0210 # integrator offset=16.5 us - ADJUST FINE OFFSET
    010C 0001 # no modulation
    0110 0003 # signal size = 3 bytes
    010D 0099 # -++- int pattern
    010E 0000 # NO OFFSET - review if needed
    010F 0000 # NO OFFSET - review if needed
    0112 0000 # no decimation

    You need to make some adjustment to the registers below:

    Adjust register 0x0104: work with register 0x0105 and/or 0x0106 and adjust the TIA gain accordingly to avoid TIA saturation, recommended output at 70% full scale (8192 LSB per pulse as full scale. For instance, for 4-pulse config with chopping by register 0x010D, 70% full scale is 8192x4x0.7 = 23,000 LSBs)

    Adjust register 0x0105/0x0106 for LED current: please note at anytime only one group of LED drivers can be used, either LED1A/2A/3A/4A or LED1B/2B/3B/4B, not both.

    Adjust register 0x0104: increase the pulse number to multiples of 4 to improve SNR

    Adjust register 0x010B: change the integrator offset with a reflector setup to optimize the zero-crossing. Please note the zero-crossing changes with the TIA gain so the optimal integrator offset needs to be optimized for each TIA gain.

     

    Hope the information above helps.

     

    Regards,

     

    Glen B.

  • Hi,

    I would request you to verify the PPG logs with respect to the register settings.

    Please find the attached sheet which is having the sample PPG waveforms and entire register settings.

    Looking forward for your comments

    Thanks

    Sudharsan

Reply Children
  • 0
    •  Analog Employees 
    on Jun 25, 2021 4:27 PM in reply to SK377

    Hi Sudharsan,

    The data in your spreadsheet doesn't look like PPG signal. Before we debug other issue, can you add the register 0x00B0 with 0x0010 to your config file and check if you get output 0x020100 (decimal 131328)? If you get a different number, there is something wrong with your FIFO reading. 

    Regards,

    Glen B.

  • Hi Glen,

    I did not understand that you mentioned the register address 0x00B0. 

    Are you really pointing to 0x00B0 register ?? If Yes, there is no register address 0x00B0 mentioned in ADPD4101 datasheet.

    I request you to check my register configurations that I have attached in that spread-sheet itself. I have copied the register settings which you have posted. 

    Please refer this below post...My register settings are exactly matching with that

    ez.analog.com/.../394040

    Regards

    Sudharsan

  • Hi Glen,

    Please check the Raw PPG data and the overall our register settings.

    I request you to review the below spread sheet

    XLSX

    Regards,

    Sudharsan

  • Hi Glen,

    These all the below register setting which I have specifically changed.

    Reg:       Data:

     0x0100   0x4000  //Enabled channel-2

     0x0107   0x0104  //ADC pulse = 4
     0x0109   0xFF0A  //LED pulse-width and offset
     0x010D   0x0099  //Register pattern -++-

    Please check the Raw PPG data which I have collected and Please don't forget to reply for the below also

    " I did not understand that you mentioned the register address 0x00B0. 

    Are you really pointing to 0x00B0 register ?? If Yes, there is no register address 0x00B0 mentioned in ADPD4101 datasheet "

    Regards,

    Sudharsan

  • 0
    •  Analog Employees 
    on Jun 28, 2021 6:57 PM in reply to SK377

    Hi Sudharsan,

    You data doesn't look like PPG signal. There are a few strange settings in your config, including

    -  [0100]4000   # it looked like you enabled both CH1 and CH2; however, your register [0102]4000 indicates that only IN8 connecting to CH2. When you have CH2 enabled,  both CH1 and CH2 data are written to FIFO with size defined by resigter [0110]0003.

    -  [0109]FF0A  # indicate LED pulse width of 255us with 10us offset. What exactly do you plan to achieve? The typical LED pulse is 2us or 3us.

    -  [0104]03C0 and [0106]0036 # What is the distance between your LED and PD? With TIA gain of 200k and LED3A current of 0x36 (or 81mA), the TIA may be saturated already.

    With regard to register 0x00B0, it is not published in the datasheet. We suggest customers this register when we suspect there is an issue with the I2C or SPI FIFO reading.

    I strongly recommend that you contact your local ADI application engineer for a meeting with us so that we can review your design and solve your problem more efficiently. 

    Regards,

    Glen B.