Access other pins while tft shield installed

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1

hi,

Very simple question I hope, but my searches have failed. What's the best way to access unused GPIO/data pins on a Mega while a (NON SPI) tft shield is in place.

For example if I want to access SDA,SCL and the other unused tx/rx pins .... I am not keen on soldering on to the mega if I can avoid it.

Can I add more pins to the shield that then plug into unused pins and then solder to the shield.

This must be a common problem e,g adding clock, temp or wifi modules to a TFT set up

Thanks

2

What shield(s) do you have?

The Mcufriend 8-bit UNO shields let you use A6-A15, D14-D53

The Mcufriend 16-bit MEGA2560 shields let you use A0-A15, D8-D13, D14-D21

The HX8357B 16-bit MEGA2560 shield let you use A0-A15, D0-D13, VIN, GND, GND, 5V.

You can place some regular right-angle header strip in the "available" spots.

Since you can not get at GND or 5V with the Mcufriend shields, you need to attach to the ICSP 3x2 header for 5V, 0V and the SPI pins.

What I have never understood: Why is there no access to the XCKn pins for any of the four USARTs?

Even more mystery: Why does anyone want more GPIO?

David.

3

Hi David,

Thank you - how did I miss that. Right angle headers !!!!!!!!!!!

Normal straight pins bump into the shield

I must have been looking at it from the wrong angle. :confused: :confused: :confused:

Thanks again.

4

Standard Adruino style long pin socket strip works well too.

Manually bend the pins at right angles close to the socket body by pressing/bending against a flat surface. To get the socket strip to fit close to the mother board crop 3 mm off the leads.

This approach has 3 advantages:

  1. The plastic body provides some protection from shorting to PCB/contacts etc on the board/shield above.
  2. This pins penetrate deeply into the Adruino board to give good contact and stability
  3. It provides a socket, so is easy to link to strip proto boards with the typical pin leads provided

See pictures.

Edit: Seeing if I can link in photos directly into the post... yay, it works!

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Hi rowboteer,

Thank you ... your second photo nailed it , excellent solution

I can use yours while developing the project (easy to reconfigure).

and David's right angle headers for final build where I solder.

I am so glad I asked

Thanks again.......... on to ebay ..,,,,again...

6

That is a neat idea. i.e. right-angle female headers if you use male-male jumper leads.

Personally, I tend to use female-female jumper leads. So right-angle male headers work fine for me.

Note that both styles of header prevent any shorts to the shield by their plastic body.

David.

7

cblx5:
Thanks again.......... on to ebay ..,,,,again...

An eBay search for "arduino female header 10 pin" usually does the job.

The ones from China tend to have less gold plating on them but they seem to work OK.

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