Trying to tri-state miso pin on RA8875

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JMC17
 
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Trying to tri-state miso pin on RA8875

Post by JMC17 »

Hey there! I was wondering, do you guys have a tutorial on doing a tri-state for the miso pin?
I've looked around and did some attempts with what I found but I couldn't get it to work.
My last attempt is attached to this post.
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dastels
 
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Re: Trying to tri-state miso pin on RA8875

Post by dastels »

Not that I am aware other than the mention at viewtopic.php?p=323058#p323058

Using an 75HC125, MISO from the display board goes to the input of one of the 74HC125's buffers, the output of the buffer goes to the MCU board's MISO pin, and the CS for the display board goes to the buffer's enable pin (as well as the display board's CS pin).

Dave

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JMC17
 
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Re: Trying to tri-state miso pin on RA8875

Post by JMC17 »

Thanks!
How about the MOSI and SCK pins? There's only one pin of each on my arduino. How do I connect multiple MOSI/SCK to a single respective pin? Do I make a rail for them?

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dastels
 
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Re: Trying to tri-state miso pin on RA8875

Post by dastels »

MOSI and SCK are signals from the MCU to the display board, and thus don't have the problem. Yes, SCK, MOSI, and MISO go to each connected SPI device (the added tristate buffer is considered to be part of the display board for the purposes of connecting multiple SPI devices). The physical connection can be whatever works.

The CS and any other pins are unique for each connected device unless it's stated otherwise.

Dave

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JMC17
 
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Re: Trying to tri-state miso pin on RA8875

Post by JMC17 »

Nice! As usual Dave, you're the best.
It's working great now!

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dastels
 
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Re: Trying to tri-state miso pin on RA8875

Post by dastels »

Awesome!

Dave

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