ILI9488 MISO Fault Question

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Joined: 11/02/2018
Location: Australia
Posts: 1483
Posted: 11:57pm 02 Dec 2022      

"With the power off measure the resistance between the SDO(MISO) pin on the panel and MISO (GP16) on the Pico."

What reading do you get with the 680R connected?
Put the probes on the pin on the display and on the Pico pin so that all the connections in between are also being measured.

The two resistors look like 390R, though it's had to be certain, so about 780R total.
The angle of your photo makes it hard to see where all the jumpers go, so I can't see if it is right or not.

My test with the variable resistor showed that 680R is the best value to get both Blit and Touch working together. After you get that far we can sort out the SD card.

"I found option reset and setup needed to get lcd back to no 680R and blit working"

That you need to do that suggests you have a wrong connection somewhere.
I have not had to do that. As long as the power is off when I change things a reset is never needed.
SDO should never be directly connected to T_DO or SD_DO as that will overload the outputs. Could that causing your need to reset?

"no 680R and blit working but touch and sd card do not."

Yes, that is the whole point of adding the extra components.