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Need help clarifying 2.8" TFT LCD shield version
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Need help clarifying 2.8" TFT LCD shield version

by nxpeco on Tue Jan 07, 2020 10:22 pm

We've been recommending the 2.8" TFT cap touch shield for our emWIN demos in MCUXpresso SDK (for NXP's Cortex-M based MCUs, so Arduino, Cricuit python code, etc doesnt help us much.) The problem is that this shield seems to have undergone some revisions and (1) we cant determine which version is which and (2) can't find the schematic for the most recently received versions. We tried what was on github (marked as from 5 months ago) and it doesnt have the IOREF pads I mention below. We need this information to get these latest shields working with our boards and hence be able to update our users on how to configure them to use with our boards and software. Our boards use standard Arduino UNO R3 SPI/I2C connections.

The attached photo is of the (apparently) older board. The "newer" board has solder pads for IOREF which arent on the older one, and the 3 solder pads adjacent to the 2x3 connector are shorted (which seems to be opposite to what the tutorials and circuit python info says).

Any help would be appreciated.
Attachments
older_LCD.jpg
older_LCD.jpg (206.67 KiB) Viewed 83 times

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Re: Need help clarifying 2.8" TFT LCD shield version

by nxpeco on Thu Jan 09, 2020 10:04 pm

No answer yet... but here's a pic of the "newer"(?) board
Attachments
newer_shield.jpg
newer_shield.jpg (29.04 KiB) Viewed 63 times

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Re: Need help clarifying 2.8" TFT LCD shield version

by adafruit_support_mike on Fri Jan 10, 2020 4:57 am

From the product page:

As of Oct 26, 2018 this board has the I2C pullups connected to IOREF rather than 5V so it's more compatible with 3.3V boards.

All of the connections and configuration should be the same as in the tutorial, but the I2C pul-up resistors will automatically connect to the right voltage for 3.3V or 5V boards.

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Re: Need help clarifying 2.8" TFT LCD shield version

by nxpeco on Fri Jan 10, 2020 2:47 pm

Thanks - I see the tutorial does reference the newer board. What was confusing us was that we had some older boards where the default was NOT to connect the SPI signals to the 2x3 header. Once I made those changes (and also soldered IOREF to 3.3V) its working for our systems.

It would help to make identifying board revisions clearer, as there are still some of the older boards in circulation. The newer board seems to have no identifying revision at all whereas the older board says v2.3.

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Please be positive and constructive with your questions and comments.