Synchronizing ADALM-Pluto SDRs Using GPIO Pins and TDD Engine in MATLAB

Yes, there is an excellent example from MathWorks here:

https://github.com/mathworks/Phaser-Control-with-MATLAB/tree/main

For example, follow the FMCW_Range_Doppler_Lab.mlx in the Workshop folder.  It shows how the tddn properties are used for Phaser and Pluto.  Beyond that, there is more information on the GPIO pins here:

https://www.youtube.com/live/PVlWK-39cCw?si=wh6pSJMfWwiJrJxQ&t=26965

Hi Jon,

Thanks for your reply. I saw the setupLabRadar.m script where it has a sequence of commands to use the TDD engine via MATLAB. Specifically the following:

% Setup the TDD engine
bf_TDD = setupTddEngine();
tStartRamp = 0;
tStartCollection = 0;
bf_TDD.PhaserEnable = 1;
bf_TDD.Enable = 0;
bf_TDD.EnSyncExternal = 1;
bf_TDD.StartupDelay = 0;
bf_TDD.SyncReset = 0;
bf_TDD.FrameLength = tpulse*1e3;
bf_TDD.BurstCount = nPulses;
bf_TDD.Ch0Enable = 1;
bf_TDD.Ch0Polarity = 0;
bf_TDD.Ch0On = tStartRamp;
bf_TDD.Ch0Off = tStartRamp+0.1;
bf_TDD.Ch1Enable = 1;
bf_TDD.Ch1Polarity = 0;
bf_TDD.Ch1On = tStartCollection;
bf_TDD.Ch1Off = tStartCollection+0.1;
bf_TDD.Ch2Enable = 1;
bf_TDD.Ch2Polarity = 0;
bf_TDD.Ch2On = 0;
bf_TDD.Ch2Off = 0.1;
bf_TDD.Enable = 1;

My question is how can I make the Pluto SDR at the header pin L10P (PL_GPIO_0) output a trigger? I hooked up an oscilloscope to L10P and did not observe any square wave with the following code I wrote.

% Define the URI for the Pluto SDR
plutoURI = 'ip:pluto1'; % Replace with the URI of your Pluto SDR

% Create the TDD engine object
bf_TDD = adi.PlutoTDD('uri', plutoURI);

% Disable the TDD engine to make changes
bf_TDD.Enable = 0;

% Configure GPIO pins for output
bf_TDD.Ch0Enable = 1; % Enable output trigger on L10P
bf_TDD.Ch0On = 10; % Pulse on duration (in milliseconds)
bf_TDD.Ch0Off = 10; % Pulse off duration (in milliseconds)

% Set burst count for pulse generation on L10P
bf_TDD.BurstCount = 0; % Example: repeat continually

% Enable external synchronization
bf_TDD.EnSyncExternal = 1;

% Re-enable the TDD engine after making changes
bf_TDD.Enable = 1;

% Trigger the TDD engine programmatically
bf_TDD.SyncSoft = 1; % Soft-sync the TDD engine

Any help would be great. I want to verify the trigger pulse coming out of L10P this way I can daisy chain it to L12N - PL_GPIO_1 on the other CN0566 + Pluto SDR's I have.

Thanks.

Thomas

I believe all of that is correct, except that you need to delete "bf_TDD.SyncSoft = 1;

Then apply an external GPIO pulse to the L12N pin.  You should see the number of pulses that you programmed coming out of the L10p pin

Thanks, for your replies, Jon. They are much appreciated!

However, just to get something straight, I was under the impression that the L10P pin outputs a trigger on its own? What it sounds like you are saying is no, I have to supply my own pulse from a separate signal generator at the GPIO L12N pin in order to see a pulse coming out of the L10P pin?

Thanks for the clarification here.

Thomas

Yes, you can trigger pulses to be generated on L10P in one of two ways:
1. Apply a external signal pulse to L12N.  This pulse will then be time aligned with the start of the L10P output pulses.

2.  Use the "SyncSoft" attribute.  This will also start the L10P pulses, but without using the L12N pin.  

Unfortunately with these changes you describe above, following 2.) from your response and with the code adjustments you suggested prior, I could not observe pulses on L10P while using SyncSoft with an o-scope on L10P. I even verified that I had the correct parameters set in the TDD engine. I must be doing something incorrect here... Thanks for all the help.

Try to follow the example here:
https://github.com/mathworks/Phaser-Control-with-MATLAB/blob/main/workshop/helpers/setupLabRadar.m

So EnSyncExternal and PhaserEnable need to be 1, even for SyncSoft. And FrameLength is in ms, so probably set that to 1, instead of 10000, and try increasing burst count to 5. That should give 5 pulses, spaced 1ms apart. And also program CH0, Chan1, and CH2. All 3 need to be set.  So use the parameters from that example and you’ll get something like this:

bf_TDD = adi.PlutoTDD('uri', plutoURI);
bf_TDD.PhaserEnable = 1;
bf_TDD.Enable = 0;
bf_TDD.EnSyncExternal = 1;
bf_TDD.StartupDelay = 0;
bf_TDD.SyncReset = 0;
bf_TDD.FrameLength = 1;
bf_TDD.BurstCount = 5;
bf_TDD.Ch0Enable = 1;
bf_TDD.Ch0Polarity = 0;
bf_TDD.Ch0On = 0;
bf_TDD.Ch0Off = 0.1;
bf_TDD.Ch1Enable = 1;
bf_TDD.Ch1Polarity = 0;
bf_TDD.Ch1On = 0;
bf_TDD.Ch1Off = 0.1;
bf_TDD.Ch2Enable = 1;
bf_TDD.Ch2Polarity = 0;
bf_TDD.Ch2On = 0;
bf_TDD.Ch2Off = 0.1;
bf_TDD.Enable = 1;

% Set transmit waveform
tx(txWaveform);

% Trigger burst pulses
bf_TDD.SyncSoft = 1;

% Capture pulses
data = rx();

Hi Jon,

Thanks for this! I was able to get it working where the L10P output pulses according to my settings. My next question is the following: Can I use the output trigger pulse from L10P to self trigger the same Pluto by feeding the L10P pulse back into the L12N pin?

Thanks, 

Thomas

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Below is reference code that I used to based on the above code you supplied but I made removed many settings to see what was the least amount of code I needed for it to work as I wanted. Your code above did not work for me right away, I had to first call bff_TDD(); before changing bf_TDD values, else in my bf_TDD all values would be NaN, doing this first ensured I properly set bf_TDD values.

bf_TDD = adi.PlutoTDD('uri', plutoURI);
bf_TDD(); % Must be here to properly set bf_TDD values, else bf_TDD will be filled with NaNs

Ch0On = 1; % Pulse width in ms
DutyCycle = 20; % Desired duty cycle in percentage (e.g., 20%)

% Calculate FrameLength based on Ch0On and DutyCycle
FrameLength = (Ch0On / DutyCycle) * 100; % FrameLength in ms

% Configure Pluto SDR
bf_TDD.Enable = 0;
bf_TDD.FrameLength = FrameLength; % Automatically calculated
bf_TDD.BurstCount = 0;
bf_TDD.Ch0Enable = 1;
bf_TDD.Ch0On = Ch0On; % Pulse width in ms
bf_TDD.Ch0Off = 0; % Not used in this case
bf_TDD.Enable = 1;

% Set transmit waveform
% tx(txWaveform);

% Trigger burst pulses
bf_TDD.SyncSoft = 1;

% Capture pulses
% data = bf_TDD.rx(); 

Hi Jon, just following up once again to my question from 11/05/25 above, let me know if it is possible.

Thanks.

Thomas

Hi Jon, just following up once again to my question from 11/05/25 above, let me know if it is possible. See below additional question related to all this.

Thanks.

Thomas

Hi Jon, just following up once again to my question from 11/05/25 above, let me know if it is possible. See below additional question related to all this.

Thanks.

Thomas