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METRO and 2.8" TFT Touch Shield - PINS
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METRO and 2.8" TFT Touch Shield - PINS

by whitecrane33 on Thu Mar 05, 2020 8:52 am

Hello,

I am using the METRO with 2.8" TFT Touch Shield for Arduino w/Capacitive Touch. No I would like to know which Pins are not used from METRO? I want to use a DHT11 and one or two 4 PIN Fans. On the Backside of the shield there is a possibility to use jumpers for PIN#7, Pin#5, PIN#11, PIN#12 and Pin#13, so I could solder my devices directly on the shield: Am I right?
But if I am looking on this paper here https://cdn-learn.adafruit.com/assets/a ... 1438860497 it seems like for example D0, D1, D2 and D3 are not used so I am confused.... Can somebody help me ?

Second in the instruction is described that for using this with Arduino Mega 2560 I have to solder 3 pins but itÄs also working without this pins. What does it mean and which Pins are affected?

Thanks.

whitecrane33
 
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Re: METRO and 2.8" TFT Touch Shield - PINS

by dastels on Thu Mar 05, 2020 10:27 am

From reading the guide and schematic,:
- Soldering the D5 jumper pads givers you backlight control.
- Soldering the D7 jumper pads gives you access to the touchscreen interrupt.
- The jumper pads on D11-D13 are connected by default to use the SPI functions on those pins. You can cut these and solder the jumper pads on the ICSP pins to use those as the SPI interface to the screen.
- For older Arduinos (pre R3 UNOs, fro example) you need to solder the SDA?SCL jumpers since they don't have those pins.

It works as-is with the Mega. You need to change the SPI pins that are used for the resistive touch shield.

From the schematic:
- D0-D3 are available
- D6 is available
- D8 is available
- A0-A3 are available
- D5 is available if you don't want it for backlight control
- D7 is available is you don't want to use the touchscreen interrupt

Dave

dastels
 
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Re: METRO and 2.8" TFT Touch Shield - PINS

by whitecrane33 on Thu Mar 05, 2020 10:36 am

Hi,

D11-D13 are on the shield not with jumpers. They are already cutted by default.

It will be difficult to use the other pins because everything is soldered so I have to solder it directly on backside of METRO board

whitecrane33
 
Posts: 4
Joined: Thu Mar 05, 2020 8:45 am

Re: METRO and 2.8" TFT Touch Shield - PINS

by dastels on Thu Mar 05, 2020 12:33 pm

You're right. The schematic is in error as it shows the opposite. So if you wanted to use D11-13 you could separate those, and jumper the ICSP pads, and use the ISCP SPI interface.

If you didn't want to solder directly to the Metro board, you could get a proto shield https://www.adafruit.com/product/2077, build it with stacking headers, and place it between the Metro and the TFT shield. Then you could connect to the desired pins on the proto shield

Dave

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Re: METRO and 2.8" TFT Touch Shield - PINS

by whitecrane33 on Fri Mar 06, 2020 3:34 am

So D11-D13 are also not used by default because they are not connected to the pads closed to them.

On the shield SPI jumpers als connected to ICSP but D11-D13 not connected to SPI, they are cutted by default. So there are free isn't it?

whitecrane33
 
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Re: METRO and 2.8" TFT Touch Shield - PINS

by dastels on Fri Mar 06, 2020 12:32 pm

Yes., they're not cut, but rather simply not connected, but you have the option. The ICSP is used by default (with the option of cutting those and using D11-13 instead. You are free to use D11-13 for other purposes.

Dave

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Re: METRO and 2.8" TFT Touch Shield - PINS

by whitecrane33 on Sat Mar 07, 2020 4:16 am

Hi, yesterday I tried it but it seems that Pin13 is used by the tft because if I set it for the temperature sensor the TFT is not working. I also tried Pin 12. Strange :)

whitecrane33
 
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Please be positive and constructive with your questions and comments.