OPT3101: Averaging when multiple illumination channels are used

Olga Pages

Part Number: OPT3101

Hello Alex,

We are using a custom board based on the OPT3101 IC in which the three illumination channels are used. The SDK is being used to calibrate the board and also to measure. The num_sub_frames and num_avg_sub_frames are configured to be 4096. The tx sequence defined is TX0-TX1-TX2-TX0-TX1-TX2. When the TESTING_LIVE_VIEW is run, the three LEDs light up when it is their turn but only data from one LED is shown in the terminal until there are approximately 30 samples obtained. At this point another channel starts showing measurements and the same happens with the third channel when 80 samples are obtained. We would like to understand the OPT3101 behavior when three illumination channels are being used because now our sensor does not respond to new targets until more or less 30 measurements are taken (taking into account that the time between sample and sample is 0,98 seconds).

Best regards,

Olga

over 3 years ago

0 Alex Bhandari-Young over 3 years ago

TI__Mastermind 25895 points

Hi Olga,

At 4096 subframes device will take 4096/4Hz = ~1 second per frame. Each channel is time multiplexed so the device will take data on ch0, 1, and then 2. However, we should expect each channel to refresh about every 3 seconds rather than the 30 seconds you are seeing. I am not sure why this would be. Have you used the configurator tool to generate the config file for device in the SDK? If so can you share a screenshot of this config?

Best,

Alex

0 Olga Pages over 3 years ago in reply to Alex Bhandari-Young

Prodigy 85 points

Hi Alex,

I use the configurator tool to generate the configuration file. The screenshot is attached below:

Thanks!

Olga

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

Will check this and get back this week on this.

Best,

Alex

0 Olga Pages over 3 years ago

Prodigy 85 points

Hi Alex,

Thanks!

Best regards,

Olga

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

I do not see any issues in your configuration here so not sure why you are seeing these longer times. Using the EVM and the EVM GUI are you able to replicate this issue?

Best,

Alex

0 Olga Pages over 3 years ago

Prodigy 85 points

Hi Alex,

With the EVM GUI I am not able to configure 3 tx channels so I can not replicate this issue.

Best,

Olga

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

If you place your board into single channel mode do you still see the issue?

Best,

Alex

0 Olga Pages over 3 years ago

Prodigy 85 points

Hi Alex,

When I configure my board to single channel mode I don't observe this behavior.

Best,

Olga

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

Can you dump all registers from the device and send to me as text file to check? Also you are supplying a clock input to the device for frequency correction?

Best,

Alex

0 Olga Pages over 3 years ago in reply to Alex Bhandari-Young

Prodigy 85 points

Hi Alex,

I attach the text file below. I am supplying a clock input to the device of 125 kHz.

Best,

Olga

Fullscreen OPT3101_registers_list.txt Download

OPT3101_configuration.cpp

void OPT3101::device::initialize(void) {
	
	this->reg.tg_ovl_window_start = 7000; // //Overload flab observation window
	this->reg.en_temp_conv = 1; // //Enables the internal

	this->reg.clip_mode_fc = 1; // //Enables Clip mode for Frequency correction
	this->reg.clip_mode_temp = 0; // //Disables Clip mode for Temp coff phase correction
	this->reg.clip_mode_offset = 0; // //Disables Clip mode for phase offset correction
	this->reg.iq_read_data_sel = 3; // //Enables 16 bit frame counter
	this->reg.iamb_max_sel = 5; // //Sets maximum ambient support

	this->reg.en_temp_corr = 0; // //Enables Temperature Correction

	this->reg.gpio1_obuf_en = 1; // //Enabled output buffer on GPIO1 pin
	this->reg.gpo1_mux_sel = 2; 	    // //select dig_gpo_0 on gpio1
	this->reg.dig_gpo_sel0 = 9; 	// //Select Data Ready on dig_gpo_0

	this->reg.en_cont_fcalib = 1; // //Enables continuous frequency calibration
	this->reg.start_freq_calib = 1; // //Starts the frequency calibration block
	this->reg.en_floop = 1; // //Enables the frequency correction loop
	this->reg.en_auto_freq_count = 1; // //Enables automatic frequency count
	this->reg.en_freq_corr = 1; // //Enables digital frequency correction
	this->reg.sys_clk_divider = 8;  // //Divider for system clock
	this->reg.ref_count_limit = 20480; // //Counter limit
	this->reg.gpio2_obuf_en = 0; // //Disables output buffer on GPIO2
	this->reg.gpio2_ibuf_en = 1; // //Enables ref clock input of GPIO2


#ifdef AVG512
	this->reg.num_sub_frames = 511; // //Sub frames count
	this->reg.num_avg_sub_frames = 511; // //Average frames count
	this->reg.xtalk_filt_time_const = 1; // //Crosstalk filter time constant
	this->reg.tg_seq_int_start = 9850; // //Sequence Start
	this->reg.tg_seq_int_end = 9858; // //Sequence End
	this->reg.tg_seq_int_mask_start = 511; // //Same as AvgFrame Count
	this->reg.tg_seq_int_mask_end = 511; // //Same as AvgFrame Count
#endif	

#ifdef AVG4096
	this->reg.num_sub_frames = 4095; // //Sub frames count
	this->reg.num_avg_sub_frames = 4095; // //Average frames count
	this->reg.xtalk_filt_time_const = 0; // //Crosstalk filter time constant
	this->reg.tg_seq_int_start = 9850; // //Sequence Start
	this->reg.tg_seq_int_end = 9858; // //Sequence End
	this->reg.tg_seq_int_mask_start = 4095; // //Same as AvgFrame Count
	this->reg.tg_seq_int_mask_end = 4095; // //Same as AvgFrame Count
#endif

	this->reg.hdr_thr_high = 25500; // //High Threshold
	this->reg.hdr_thr_low = 10650;
	
	this->reg.en_adaptive_hdr = 1;

	this->reg.illum_dac_h_tx0 = 18; // //High Current settings [100.8mA:5.6mA X 18]
	this->reg.illum_scale_h_tx0 = 0; // //Illum scale for H [100.8mA:5.6mA X 18]
	this->reg.illum_dac_l_tx0 = 13; // //High Current settings [054.6mA:4.2mA X 13]
	this->reg.illum_scale_l_tx0 = 1; // //Illum scale for H [054.6mA:4.2mA X 13]

	this->reg.illum_dac_h_tx1 = 18; // //High Current settings [100.8mA:5.6mA X 18]		//NEW
	this->reg.illum_scale_h_tx1 = 0; // //Illum scale for H [100.8mA:5.6mA X 18]		//NEW
	this->reg.illum_dac_l_tx1 = 13; // //High Current settings [054.6mA:4.2mA X 13]		//NEW
	this->reg.illum_scale_l_tx1 = 1; // //Illum scale for H [054.6mA:4.2mA X 13]		//NEW

	this->reg.illum_dac_h_tx2 = 18; // //High Current settings [100.8mA:5.6mA X 18]		//NEW
	this->reg.illum_scale_h_tx2 = 0; // //Illum scale for H [100.8mA:5.6mA X 18]		//NEW
	this->reg.illum_dac_l_tx2 = 13; // //High Current settings [054.6mA:4.2mA X 13]		//NEW
	this->reg.illum_scale_l_tx2 = 1; // //Illum scale for H [054.6mA:4.2mA X 13]		//NEW



	this->reg.tx_seq_reg = 2340; // //Setting TX Switching order
	this->reg.en_tx_switch = 1; // //Enable TX Switching order

	this->reg.tg_en = 1; // //Enables Timing Generator


#ifdef AVG512
	this->configurationFlags_xtalkFilterTau = 1; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_monoshotMode = false; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_xtalkSettlingOneTauInMilliSeconds = 256; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_xtalkSettlingOneTauInDataReadyCounts = 2; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_frameTimeInMilliSeconds = 128; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_avgFrameCountExponentOfTwo = 9; // //This is not a register but a settings flag for the SDK
#endif 	

#ifdef AVG4096
	this->configurationFlags_xtalkFilterTau = 0; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_monoshotMode = false; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_xtalkSettlingOneTauInMilliSeconds = 1024; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_xtalkSettlingOneTauInDataReadyCounts = 1; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_frameTimeInMilliSeconds = 1024; // //This is not a register but a settings flag for the SDK
	this->configurationFlags_avgFrameCountExponentOfTwo = 12; // //This is not a register but a settings flag for the SDK
#endif
}

OPT3101::device::device(void) :
	configurationFlags_isTXChannelActive{true,true,true}, // MODIF
	configurationFlags_isRegisterSetActive{true,true} {}

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

Checking these settings.

Best,

Alex

0 Olga Pages over 3 years ago

Prodigy 85 points

Hi Alex,

Have you seen something interesting in the settings?

Thanks!

Olga

0 Alex Bhandari-Young over 3 years ago in reply to Olga Pages

TI__Mastermind 25895 points

Hi Olga,

Apologies for the delay. We will provide a response here tomorrow.

Best,
Alex

0 Alex Bhandari-Young over 3 years ago in reply to Alex Bhandari-Young

TI__Mastermind 25895 points

Hi Olga,

We have had some delay here. Will provide a response within next two days.

Best,

Alex

0 Brent Elliott over 3 years ago in reply to Olga Pages

TI__Expert 6800 points

Hi Olga,

It seems that I have managed to replicate a similar behavior to what you have described in the first post. I need to check this further to confirm this. Can you try starting the device at the fastest frame rate and then updating the frame rate register to your desired value and check the results? Also, have you looked at the behavior at different frame rates? Does the problem persist and if so, how does it behave?

Thank you,

Brent Elliott

0 Olga Pages over 3 years ago

Prodigy 85 points

Hi Brent,

I have checked your questions:

Can you try starting the device at the fastest frame rate and then updating the frame rate register to your desired value and check the results?

I am measuring using the SDK and the frame rate cannot be changed once the program is running. The problem persists with this test.

Also, have you looked at the behavior at different frame rates? Does the problem persist and if so, how does it behave?

I have looked the behavior at 2048 (num_avg_sub_frames) and the problem persists. It seems that the sensor does the average for each sample during aproximately 15 samples for TX0, and then starts measuring with TX1 repeating the operation (the same with TX2). In other words, there is only one channel updating its values during 15 samples while the other two channels maintain the previous values. When there is a distance change to detect, only 1 channel updates its value at real time. The next channel updates its measurement after 15 samples, which are more or less 25 seconds.

+1 Brent Elliott over 3 years ago in reply to Olga Pages

TI__Expert 6800 points

Hi Olga,

I have looked through the SDK and found that there is a timing issue in the capture function in OPT3101device_Functions.cpp. To fix this you will need to comment the line that says "host->sleep(((dev->configurationFlags_frameTimeInMilliSeconds)<<1));". This line was introducing an extra waiting period which caused the data capture to occur only when one channel is updating. Since this code is time based and not interrupt based, the channels will not update in order 100% of the time, so you may notice a channel being skipped every 40 samples or so.

Let me know if you have any other questions.

Thank you,

Brent Elliott

0 Olga Pages over 3 years ago in reply to Brent Elliott

Prodigy 85 points

Hi Brent,

Thank you very much, this has solved the issue.

Best regards,

Olga

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OPT3101: Averaging when multiple illumination channels are used