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How do the SPI communication between two f28379D launchpads?

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Hi, I need help for the SPI communication of two launchpads f28379D. when I enable the external mode of the two launchpads, there is no transmission because the displays of the models show zero instead of 1:9 o 21:24. any suggestion or fix of the attached model I would be grateful. Happy new year.
asked Dec 31, 2020 by efrain ibaceta (36 points)
here I have screenshots of the real time simulation.

1 Answer

0 votes

Hi Efrain,

Your model looks good to me. I don't have two 28379D launchpads with me, so I replaced one of the 28379D launchpads with a 28377S launchpad, as attached. I get the expected results.

Regards,
Manu



 

answered Jan 4 by Manu Parimi (297 points)

Hi Manu,

it's not necessary to have two launchpads f28379D since you can make the slave module

. In another hand, as I commented in another question (http://forum.plexim.com/5062/how-fix-the-overruns-issue-with-slave-module-launchpad-28379d?show=5084#a5084), I don't get overruns in the simulation but it doesn't show numbers at the displays as in the attached photo. For that reason, I aks for the hardware implementation (pin-set configuration) or any technical solution for this particular issue due to don't show numbers in the displays blocks in the case of a one launchpad XL f28379D that acts as Master and Slave at the same time.

Hi Efrain,

I responded to your comment in that same thread.

Manu
Hi manu,

you were right. The green board launchpad interface made the glitch of the F28379D. Do you know how to enable the SPI communication with the green board launchpad interface connected to the controller F28379D?

regards
This was answered by email. But I wanted to enter that answer here to resolve this post.

From the launchpad interface manual here -- https://plexim.com/sites/default/files/launchpadinterfacemanual.pdf, it can be observed that a few SPI signals are connected to digital signals, causing interference, and creating this issue. One solution could be to use header connectors to isolate the SPI pins on the red launchpad board from the green interface board.

Also, to prevent overrun errors—

1. Do not probe the “CLK” signal (via the RT Box). That’s what will push the model into getting overrun errors.
2. Make sure to provide a common power supply to both the launchpads.
3. As stated in the “Help” section of the SPI blocks, the master is not allowed to start transmitting before the slave is up and running. If the slave is booting up while the master is transmitting, then it may receive an incomplete first message, from which it will not be able to recover.

Regards,
Manu
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