ADPD144RI - SPO2 data read EXAMPLE

Hi there,

Please check the thread at the link below:

https://ez.analog.com/optical_sensing/f/q-a/165141/adpd144ri-software-code-example

Regards,

Glen B.

Dear Glen, 

I am writing on behalf of Suresh. The github link contains drivers for ADPD10X. It does not contain specifically for ADPD144. Please let us know if there is any other location where specific files for ADPD10X is placed. 

In the meantime, We have tried to test our PCB with ADPD144. 

We have programmed the register Setting values as suggested in the datasheet and also in engineering Zone forum link: (https://ez.analog.com/optical_sensing/f/q-a/165141/adpd144ri-software-code-example) have been used to program.

Initially, We tried to read the reset values of each register. The values read matched with the expected values provided in Table-13 (Register Listing) of datasheet.

We are using Poling method to read the data. Although, We have used the same register values as suggested in datasheet or Forum, The data observed in the data registers 0x64 to 0x7F are 0x0000.

We also placed the finger on the ADPD1443I, the LED did not turn on also, the data registers still sshowed 0x00000

We have followed the startup sequence suggested in the datasheet. Initially, register 0x10 is written 0x0001 during writing all the registers and later after all the registers are written, register 0x10 is written 0x0002 to enter into normal operation mode.

The register values that we programmed and the values we readout are shown below.

We also have tried to verify with respect to hardware. 

1. The 3V and 1.8V voltages are working fine.
2. We are using internal LEDs. Datasheet mentions that the voltage appears on LEDX1 and LEDX2 Pin. The voltage we have observed was LEDX1=1.68V and LEDX2=2V.
3. The Value of capacitor used on CVLED is 1uF. The current setting of LED1 (Register 0x23) is 100mA and LED2 (Register 0x24) is 130mA, LED Pulse Width is 3uSec. Can you confirm if the example formula in Page 19 of datasheet is correct. The minimum LED voltage is considered as 4V in the equation however, minimum LED voltage is 3V.
4. The value of capacitor used on CVREF is 1uF. The Voltage measured on Cvref is 0V.

The schematic we have used is shown below.

Please let us know if you see any issues. We are unable to get any data (The data registers are reading 0x0000) and LED is also not turning ON when we keep the finger.

Thanks

1_data.txt

2_data.txt

Dear Glen, 

We are facing issue with resetting the FIFO contents. When we try to capture data multiple times, We found that, the data in FIFO was not getting updated. Please find the attached Text files 1_Data.txt and 2_DATA.txt. You can see that, data in the data FIFO is the same in both iterations.

Hence, We tried to reset the FIFO based on the steps mentioned in the Startup sequence section.

We have written a application code, to perform read operation for 4 times in a loop. After each read operation, The FIFO is reset and when read operation is performed again in loop the FIFO is resetting properly and new data is getting updated in the FIFO. 

However, If We reset the board and then perform the read operation, We are observing the Previously captured data (that was observed before resetting board) is read in the data registers.

Request you to let us know if you see any mistake we are doing. 

Please find the snippet below containing data that is read and register settings we are using to clear the FIFO after each read. We have followed the steps provided in startup sequence to clear the FIFO.

Hi there,

The Vref should be at 1.265V. The voltages at LEDX1 and LEDX2 looked fine , meaning there is  voltage drops across the integrated red and IR LEDs. 

Were you able to see the red LED glowing with the config I posted?

With regard to the FIFO read, I will ask our firmware colleague to comment.

Regards,

Glen

Dear Glen, 

The Red led did not glow after we loaded the configuration.

What is the reason for voltage drop across LEDS. 

Hi Subbu,

Regarding FIFO read data can you share your code snippet to go through it.

Are you using AdpdDrvReadFifoData() API to readout data from FIFO?

Regards,

Sathishkumar

Hi there,

Did you set register 0x10 to 0x0002 after you loaded the config to start the data acquisition? The LEDs glow only when the ADPD144RI is in sample mode. 

When LEDX1/LEDX2 are on, there is  forward voltage across the LED(s), depending on the current. Please note that the LEDX1 and LEDX2 are current sink and only turned on during the LED pulses. The voltage at the LEDX1 and LEDX2 pins should be close to VLED when the LEDX1/LEDX2 are off.  

Regards,

Glen B.

Dear Sathish, 

Please find the attached source code. 

Briefly, We are trying to do the following:

1. Initially, We are programming the registers as per the above configuration file by putting the chip in program mode.

2. After the configuration file is loaded, We are putting device into Normal operation mode (By writing 02 to Register 0x10).

3. We are reading the data stored in registers 0x64 to 0x6b. 

4. After reading, We are clearing the FIFO  and trying to read the data again.

We also need clarification on the following.

In this code snippet.

https://github.com/analogdevicesinc/adpd-drivers/blob/master/ADPD10xx/examples/example188.c

/* Clear the FIFO */

   AdpdDrvRegWrite(0x10, 0);

   AdpdDrvRegWrite(0x5F, 1);

   AdpdDrvRegWrite(0x00, 0x80FF);

   AdpdDrvRegWrite(0x5F, 0);

According to the above code snippet, 0 is written to 0x10, which puts the chip in to standby mode and later the register programming is done to clear FIFO.

But, As per the startup sequence mentioned in datasheet, From Normal Operation mode, To clear the FIFO, We need to put the chip in to program mode and then enter necessary register values to clear FIFO and later we need to program 0x10 with 0x2 to put the device into read mode.

We would like to understand, the difference between the procedure followed in example188.c and approach suggested in datasheet to clear FIFO.

Thanks

.4617.main.txt

Hi Subbu,

I would suggest two change, since your are not using driver API's.

• Please do check the available FIFO bytes before you are going to read the FIFO data.
• In your FIFO read API enable FIFO clock before reading data (AdpdDrvRegWrite(REG_FIFO_CLK, FIFO_CLK_EN)).

AdpdDrvGetParameter() This API will give the available bytes in the FIFO. we need to ensure that required data's are accumulated in FIFO before reading it.

Regarding FIFO clear mechanism you can follow the data sheet sequence. In driver file we are following same sequence as mentioned in data sheet.

Regards,

Sathishkumar K

1.

The FIFO read API is modified to enable FIFO clock before reading
AdpdDrvRegWrite(0x0010, 0x0001);
AdpdDrvRegWrite(0x005f, 0x0001);
AdpdDrvRegWrite(0x005f, 0x0001);
AdpdDrvRegWrite(0x0010, 0x0002);

#define ADPDDrv_SUCCESS (0)
#define ADPDDrv_ERROR (-1)
#define ADPD_I2C_ADDRESS (0x64)
#include <uart_debug.h>

void main(void)
{
uint32_t LoopCnt = 0;
uint8_t value[16] = {0};
uint16_t nAdpdFifoLevelSize = 64, nAdpdDataSetSize;
uint16_t nLoopLim = 16;
uint16_t nAdpdDataSetSize = 8;
uint16_t nRetValue = 0;

AdpdDrvInit();

while (1) 
{
	nRetValue = AdpdDrvReadFifoData(&value[0], nAdpdDataSetSize);
	if (nRetValue == ADPDDrv_SUCCESS)
	{
		for (LoopCnt = 0; LoopCnt < nLoopLim; LoopCnt += 2)
		{
			UART_Print("%u ", (value[LoopCnt] << 8) | value[LoopCnt + 1]);
			nAdpdFifoLevelSize = nAdpdFifoLevelSize - nAdpdDataSetSize;
		}
	}
}
}

int16_t AdpdDrvReadFifoData(uint8_t *pnData, uint16_t nDataSetSize)
{
	uint8_t nGetFifoData, nAddr;
	nAddr = 0x60;

	AdpdDrvRegWrite(0x0010, 0x0001);
	AdpdDrvRegWrite(0x005f, 0x0001);
	AdpdDrvRegWrite(0x005f, 0x0001);
	AdpdDrvRegWrite(0x0010, 0x0002);

	if (ADPD_I2C_TxRx((uint8_t *) &nAddr, pnData, nDataSetSize) != HAL_OK)
		return ADPDDrv_ERROR;
	return ADPDDrv_SUCCESS;
}

bool ADPD_I2C_TxRx(unsigned char* pTxData, unsigned char* pRxData, unsigned int Size) 
{ 
	HAL_I2C_Master_Transmit(&hi2c2, (uint16_t)(ADPD_I2C_ADDRESS << 1), (uint8_t *)pTxData, Size, 100);
	return (HAL_STATUS_t)HAL_I2C_Master_Receive(&hi2c2, (uint16_t)(ADPD_I2C_ADDRESS << 1), pRxData, Size, 100);
}

int16_t AdpdDrvRegWrite(uint16_t nAddr, uint16_t nRegValue)
{
	uint8_t anI2cData[3];
	anI2cData[0] = (uint8_t)nAddr;
	anI2cData[1] = (uint8_t)(nRegValue >> 8);
	anI2cData[2] = (uint8_t)(nRegValue);

	if (ADPD_I2C_Transmit((uint8_t *)anI2cData, 3) != ADI_HAL_OK)
		return ADPDDrv_ERROR;

	return ADPDDrv_SUCCESS;
}

AdpdDrvInit()
{
	//Init code
}

2.

I will add the API to check the available FIFO bytes before reading the FIFO data. I will update this code and share.

I was having indefinite loop to read the data. This code was shared above.

Now I have changed the indefinite loop - while (1) to read the fifo data, based on the bytes of data available to readdata size.
Now after adding this API - AdpdDrvGetParameter(), I could only get 128-bytes of data.
I could see only 4 reads and each read gets us 32 byte of Data (Total 128-BYTES) . After each read fifo reset is happening, but after the board is power cycled, We could still read the cached data and that is the same data we have received before power cycle.

main_v3.rtf

Dear Glen,

Yes, We have set the register 0x10 to 0x0002 after the configuration is loaded. Although, We have done this, the LEDs are not glowing. I have measured the 3V, 1.8V supplies, They are fine. 

Can you share the sample data that is expected when We load the suggested configuration both in open condition and when finger is placed over the device.

What is the maximum value of pulse width that we can set..?

Dear Glen,

Yes, We have set the register 0x10 to 0x0002 after the configuration is loaded. Although, We have done this, the LEDs are not glowing. I have measured the 3V, 1.8V supplies, They are fine. 

Can you share the sample data that is expected when We load the suggested configuration both in open condition and when finger is placed over the device.

What is the maximum value of pulse width that we can set..?